Abstracts Book

Abstracts Book

Index s

Page

PL. Plenary Lectures

3

SY. Symposia

11

PO. Posters

79

Plenary Lectures

17th National Congress of the Spanish Society of Neuroscience

Abstracts: Plenary Lectures

WHO WINS AND WHO LOSES? BRAIN ENERGY METABOLISM ON THE LINK BETWEEN STRESS, ANXIETY AND SOCIAL COMPETITION C. Sandi Brain Mind Institute, Swiss Federal Institute of Technology Lausanne (EPFL), Switzerland

Stress and anxiety can greatly affect individuals’ social competitiveness, as observed in our work in both humans and rodents. Our recent studies highlight brain energy metabolism, particularly mitochondrial function in the nucleus accumbens, as a key mediating mechanism of the impact of stress and anxiety on social competition. Evidence includes data from 1HMRS spectroscopy in humans and rodents and analyses of different features of mitochondrial function (respiration, membrane potential, ATP and ROS production), behavior and peripheral metabolism (CLAMS; echoMRI), as well as genetic and pharmacological manipulations. We underscore a role for Sirtuin 1 in the mediation of early life stress effects on social behaviors and for mitochondrial complex I and II on the link between anxiety and social competition. Our findings highlight mitochondrial function as a potential therapeutic target for anxiety-related social dysfunctions.

www.congreso-senc.com



GENETIC DISSECTION OF NEURAL CIRCUIT ASSEMBLY AND FUNCTION L. Luo Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA

This talk will discuss our recent work on the development and function of neural circuits in flies and mice. Discussion of development will focus on cellular and molecular mechanisms that mediate the establishment of wiring specificity between pre- and postsynaptic partners. Discussion of function will focus on TRAPing active neurons to interrogate circuits involved in thirst motivation and remote memory.


Symposia

Symposia s

Page

SY01. Gene Expression in Learning and Memory

11

SY02. Controlling neuronal activity with light: fundamental and therapeutic applications

15

SY03. Molecular basis of adult neurogenesis: from epigenetic, to transcriptional and metabolic control

19

SY04. Adaptive coding of sensory signals for efficient behavioral performance

23

SY05. Advanced MRI contrasts to investigate brain inflammation and degeneration

27

SY06. Schwann cells in nerve function and repair

31

SY07. In vivo electrophysiology and imaging to unveil neuronal network functioning

35

SY08. Neural basis of normal and pathological oscillations

39

SY09. Basal Ganglia Circuits in Health and Disease

43

SY10. Neuroendocrine regulation of homeostasis

47

SY11. Neuron-glia interactions: from molecules to behavior

51

Symposia s

Page

SY12. Shared principles of animal behavior across species

57

SY13. Psychosis as a disorder of neurodevelopment: insights from basic research to the clinic

61

SY14. Intellectual Disability: New Opportunities for Understanding the Neurobiology and Advancing Therapy

67

SY15. Neural cell fate determinants during cortical development in health and disease

73

Symposium SY01. Gene Expression in Learning and Memory


Session:

Symposium

Title:

Gene Expression in Learning and Memory

Chairperson

Raul Andero

Co-chairperson

Gleb Shumyatsky

Abstract

OVERALL ABSTRACT

Abstracts: Symposia

Code

SY01

Regulation of gene synthesis is one of the critical mechanisms of memory storage and this symposium will demonstrate the importance of determining molecular components of RNA transcription. As memory deficits are often part of normal ageing and are also present in several mental and neurodegenerative diseases, work presented here will also help design new treatments for patients with mental states that include memory deficits. This symposium is focused on genetics, epigenetics and transcriptomics related to memory in health and disease in both the adult and aged brain. The cutting-edge techniques used in these studies allow for new level of investigation and bring novel concepts and knowledge about brain processing. This session will discuss some of the current “hot topics” that open up new directions in the field and propose future studies. Dr. Gleb Shumyatsky´s lecture will focus on the role of activity-dependent nuclear translocation and gene transcription in determining memory strength (based on Uchida et al. Cell Reports 2017). The interactions between transcriptomics and epigenetics in gene expression will be the topic covered by Dr. Angel Barco´s lecture (Based on Lopez-Atalaya JP & Barco A. Trends in Genetics 2014). Dr. Satoshi Kida´s lecture will demonstrate how memory retrieval is dependent on the transcription factor BMAL1 (See recent similar work Ishikawa et al. eLife 2016). Epigenomic and transcriptomic regulation of hippocampus-dependent memory in a mouse model of tauopathy will be discussed in Dr. Anne-Laurence Boutillier´s lecture (See recent similar work Neidl et al. Journal of Neuroscience 2016). Recent work on epigenetic and transcriptomic mechanisms has opened up a new dimension in examining the role of gene transcription in memory processes and created new opportunities the treatment of mental states. For example, the study of transcriptomics provides a powerful approach for the design of new pharmacological drugs with the unprecedented molecular target precision, which has been unattainable until now. Furthermore, changes in various epigenetic mechanisms implicated in learning and memory can underlie many mental and neurodegenerative disorders in the brain, such Depression, Post-traumatic stress disorder, Autism and Alzheimer’s. This symposium brings together speakers specialized in different areas of neuroscience such as learning and memory, ageing and neurogenesis.

Speakers

1. 2. 3. 4.

Gleb Shumyatsky. Rutgers University Angel Barco. Instituto de Neurociencias (UMH-CSIC) Anne-Laurence Boutillier. UMR 7364 Unistra/CNRS, Université de Strasbourg Satoshi Kida. Tokyo University of Agriculture.

Contact:

Raul Andero: [email protected]

Session:

Symposium

SPEAKER 1

Code

SY01

Title:

Activity-dependent nuclear translocation and gene transcription define memory strength

Speaker

Gleb Shumyatsky

Abstract Recent publications

. a. Uchida S., Martel G., Pavlowsky A., Takizawa S., Hevi C., Kandel E.R., Alarcon J.M., & Shumyatsky G.P. (2014). Learning-induced and stathmin-dependent changes in microtubule stability are critical for memory and disrupted in ageing. Nature Communications, 5:4389 doi: 10.1038/ncomms5389. b. Martel G, Uchida S, Hevi C, Chevere-Torres I, Fuentes I, Park YJ, Hafeez H, Yamagata H, Watanabe Y, and Shumyatsky GP. (2016) Genetic demonstration of a role for stathmin in adult hippocampal neurogenesis, spinogenesis, and NMDA receptor-dependent memory. J. of Neuroscience. 36, 1185-


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Abstracts: Symposia


1202. c. Uchida S, Teubner BJW, Hevi C, Hara K, Kobayashi A, Dave RM, Shintaku T, Jaikhan P, Yamagata H, Suzuki T, Watanabe Y, Zakharenko SS, and Shumyatsky GP. CRTC1 nuclear translocation following learning modulates memory strength via exchange of chromatin remodeling complexes on the Fgf1 gene. Cell Reports. Accepted.

Session:

Symposium

Title:

Interplay of transcriptional and epigenetic mechanisms in the regulation of activity-driven gene expression

Speaker

Angel Barco

SPEAKER 2

Code

SY01


a. Ito S, et al… and Barco A (2014) Loss of neuronal 3D chromatin organization causes

transcriptional and behavioral deficits related to serotonergic dysfunction. Nat Comm. 5:4450. b. Lopez-Atalaya JP and Barco A (2014). Can changes in histone acetylation contribute to memory formation? Trends Genet 30(12):529-39. c. Fiorenza A, Lopez-Atalaya JP, Rovira V, Geijo-Barrientos E, Barco A. Blocking miRNA biogenesis in adult forebrain neurons enhances seizure susceptibility, fear memory and food intake by increasing neuronal responsiveness. Cereb Cortex 2016 Nov;135:3-12.

Session:

Symposium

Title:

Epigenomic correction of defective plasticity [and memory formation] in a mouse model of tauopathy with an acetyltransferase activator.

Speaker

Anne-Laurence Boutillier

SPEAKER 3

Code

SY01


a. Neidl R, Schneider A, Bousiges O, Majchrzak M, Barbelivien A, de Vasconcelos AP, Dorgans K,

Doussau F, Loeffler JP, Cassel JC, Boutillier AL. Late-Life Environmental Enrichment Induces Acetylation Events and Nuclear Factor κB-Dependent Regulations in the Hippocampus of Aged Rats Showing Improved Plasticity and Learning. J Neurosci. 2016 Apr 13;36(15):4351-61. b. Achour M, Le Gras S, Keime C, Parmentier F, Lejeune FX, Boutillier AL, Néri C, Davidson I, Merienne K. Neuronal identity genes regulated by super-enhancers are preferentially downregulated in the striatum of Huntington's disease mice. Hum Mol Genet. 2015 Jun 15;24(12):348196. c. Chatterjee S, Mizar P, Cassel R, Neidl R, Selvi BR, Mohankrishna DV, Vedamurthy BM, Schneider A, Bousiges O, Mathis C, Cassel JC, Eswaramoorthy M, Kundu TK, Boutillier AL. A novel activator of CBP/p300 acetyltransferases promotes neurogenesis and extends memory duration in adult mice. J Neurosci. 2013 Jun 26;33(26):10698-712.

Session:

Symposium

Title:

Regulation of memory retrieval by transcription factor BMAL1

Speaker

Satoshi Kida


SPEAKER 4

Code

SY01

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Abstracts: Symposia


a. Ishikawa, R., Fukushima, H., Frankland, P.W., Kida, S*. Hippocampal neurogenesis enhancers promote forgetting of remote fear memory after hippocampal reactivation by retrieval eLife, 5: e17464, 2016. doi: 10.7554/eLife.17464. b.Fukushima, H., Zhang, Y., Archbol, G., Ishikawa, R., Nader, K. Kida, S*. Enhancement of fear memory by retrieval through reconsolidation. eLife, 3, e02736, 2014 c. Kida, S.* & Serita, T. Functional roles of CREB as a positive regulator in the formation and enhancement of memory. Brain Research Bulletin. 105:17-24, 2014


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Symposium SY02. Controlling neuronal activity with light: fundamental and therapeutic applications


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Abstracts: Symposia

Session:

Symposium

Title:

Controlling neuronal activity with light: fundamental and therapeutic applications.

Chairperson

Pau Gorostiza

OVERALL ABSTRACT

Code

SY02

Co-chairperson Abstract

Speakers

Optogenetics and light-regulated drugs have enabled remotely controlling neuronal activity, and led to fundamental breakthroughs like the dissection of neural circuits or the remote manipulation of animal behavior. Photostimulation allows sub-micron, sub-millisecond resolution, and genetic or pharmacological specificity. In addition, clinical trials for some therapeutic applications started in 2016, most notably for vision restoration. This workshop will showcase the state of the art in this exciting field, presented by some of their pioneers. Optogenetics was chosen as the Method of the Year 2010 across all fields of science and engineering by the journal Nature Methods, and was highlighted as a breakthrough of the decade in Science magazine. After being again under the focus during the International Year of Light (2015), the photomanipulation of physiology is taking a leap forward to practical applications, including new forms of phototherapy. Many efforts in academia and industry are put on directly photosensitizing neurons to restore vision. The indirect and remote control of cellular physiology with light is also investigated, from muscle contraction and regeneration (including optical cardiac pacemakers) to insulin release or GPCR signaling. Although the use of optogenetics and light- regulated drugs have rapidly matured and become widespread, many people ask the experts why human therapeutical application are not developing faster, what are the main hurdles and what could be the most exciting prospects. To answer these questions, this symposium proposal gathers a panel of experts in the development of optogenetic tools and light-regulated drugs, and in their therapeutic applications. The presentations will cover from neural circuit manipulation to vision restoration therapies, which have a great incidence and interest in the population, and involve high economic costs. In addition, this topic will also appeal to a wide audience as it brings smart implants a step higher, and may spark fantasies of “cybernetic organisms”. 1. 2. 3. 4.

Valentina Emiliani. CNRS & Université Paris Descartes. Anja Hoffmann-Röder Sonja Kleinlogel. Bern University. Mercè Izquierdo-Serra. University Pompeu Fabra

Contact:

Pau Gorostiza. [email protected]

Session:

Symposium

SPEAKER 1

Title:

Two photon optogenetics

Speaker

Valentina Emiliani

Code

SY02


Three-dimensional spatiotemporal focusing of holographic patterns. Hernandez O, Papagiakoumou E, Tanese D, Fidelin K, Wyart C, Emiliani V. Nature Communications. 2016 Jun 16;7:11928. Spatially selective holographic photoactivation and functional fluorescence imaging in freely behaving mice with a fiberscope. Szabo V, Ventalon C, De Sars V, Bradley J, Emiliani V. Neuron. 2014 Dec 17;84(6):1157-69. Three-dimensional imaging and photostimulation by remote-focusing and holographic light patterning. Anselmi F, Ventalon C, Bègue A, Ogden D, Emiliani V. Proceedings of the National Academy of Sciences of the U S A. 2011 Dec 6;108(49):19504-9.


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Session:

Symposium

Title:

Photocontrolled peptidomimetics

Speaker

Anja Hoffmann-Röder

SPEAKER 2

Abstracts: Symposia

Code

SY02

Code

SY02


Session:

Symposium

Title:

Optogenetically restored vision in a dynamic visual environment

Speaker

Sonja Kleinlogel

SPEAKER 3


CSF-contacting neurons regulate locomotion by relaying mechanical stimuli to spinal circuits. Böhm UL, Prendergast A, Djenoune L, Nunes Figueiredo S, Gomez J, Stokes C, Kaiser S, Suster M, Kawakami K, Charpentier M, Concordet JP, Rio JP, Del Bene F, Wyart C. Nature Communications 2016 Mar 7;7:10866. Filtering of visual information in the tectum by an identified neural circuit. Del Bene F, Wyart C, Robles E, Tran A, Looger L, Scott EK, Isacoff EY, Baier H. Science. 2010 Oct 29;330(6004):669-73. Optogenetic dissection of a behavioural module in the vertebrate spinal cord. Wyart C, Del Bene F, Warp E, Scott EK, Trauner D, Baier H, Isacoff EY. Nature. 2009 Sep 17;461(7262):407-10.

Session:

Symposium

Title:

Targeted covalent photoswitches to control endogenous receptors and cellular excitability with light.

Speaker

Mercè Izquierdo-Serra

Abstract

M. Izquierdo-Serra1, A. Bautista-Barrufet1,2, A. Trapero, A1,3. Garrido-Charles1, A. Díaz-Tahoces4, N. Camarero1, S. Pittolo1, S. Valbuena5, A. Pérez-Jiménez1, M. Gay6, A. García-Moll4, C. RodríguezEscrich2, J. Lerma5, P. de la Villa7, E. Fernández4,8, M. À. Pericàs2,9, A. Llebaria3 and P. Gorostiza1,8,10 1. Institut de Bioenginyeria de Catalunya (IBEC), Barcelona, Spain 2. Institute of Chemical Research of Catalonia (ICIQ), Tarragona, Spain 3. Institut de Química Avançada de Catalunya (IQAC-CSIC), Barcelona, Spain 4. Instituto de Bioingeniería, Universidad Miguel Hernández (UMH), Elche, Spain 5. Instituto de Neurociencias (CSIC-UMH), San Juan de Alicante, Spain 6. Institut de Recerca en Biomedicina (IRBB), Barcelona, Spain 7. Universidad de Alcalá de Henares (UAH), Alcalá de Henares, Spain 8. Centro de Investigación Biomédica en Red en Bioingeniería, Biomateriales y Nanomedicina (CIBERBBN), Zaragoza, Spain 9. Departament de Química Inorgànica i Orgànica, Universitat de Barcelona (UB), Barcelona, Spain 10. Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain

SPEAKER 4

Code

SY02

Objectives. Light-regulated drugs allow remotely photoswitching biological activity and enable plausible therapies based on small molecules. However, only freely diffusible photochromic ligands have been shown to work directly in endogenous receptors and methods for covalent attachment depend on genetic manipulation. Here we introduce a chemical strategy to covalently conjugate and photoswitch the activity of endogenous proteins and demonstrate its application to restore photoresponses in degenerated retina without genetic manipulation. www.congreso-senc.com

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Abstracts: Symposia

Methods. Chemical synthesis and analytical tools were used to obtain and characterize the new photoswitchable ligands. Photoresponses induced by these compounds were evaluated, first, using whole-cell patch clamp on cell lines and neuronal cultures and finally, using extracellular multi-electrode arrays on isolated retina. Results. The novel approach is based on photoswitchable ligands containing a short-lived, highly reactive anchoring group that is targeted at the protein of interest by ligand affinity. Our targeted covalent photoswitches (TCPs) were designed for the kainate receptor channel GluK1. In this way, TCP enabled photocontrol of the activity of neurons that endogenously express the receptor, showing a robust and sustained photosensitization in the degenerated retina. Conclusions. TCPs constitute a new class of light-regulated drugs and act as prosthetic molecules that photocontrol the activity of GluK1-expressing neurons. Moreover, the modularity of the new photoswitches enables the application to different ligands and opens the way to new therapeutic opportunities. Recent publications

Optical control of endogenous receptors and cellular excitability using targeted covalent photoswitches. Izquierdo-Serra M, Bautista-Barrufet A, Trapero A, Garrido-Charles A, Díaz-Tahoces A, Camarero N, Pittolo S, Valbuena S, Pérez-Jiménez A, Gay M, García-Moll A, Rodríguez-Escrich C, Lerma J, de la Villa P, Fernández E, Pericàs MÀ, Llebaria A, Gorostiza P. Nature Communications. 2016 Jul 20;7:12221. Two-photon neuronal and astrocytic stimulation with azobenzene-based photoswitches. Izquierdo-Serra M, Gascón-Moya M, Hirtz JJ, Pittolo S, Poskanzer KE, Ferrer È, Alibés R, Busqué F, Yuste R, Hernando J, Gorostiza P. Journal of the American Chemical Society. 2014 Jun 18;136(24):8693-701. Optical modulation of neurotransmission using calcium photocurrents through the ion channel LiGluR. Izquierdo-Serra M, Trauner D, Llobet A, Gorostiza P. Frontiers in Molecular Neuroscience. 2013 Mar 21;6:3.


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Symposium SY03. Molecular basis of adult neurogenesis: from epigenetic, to transcriptional and metabolic control


- 19 -


Abstracts: Symposia

Session:

Symposium

Title:

Molecular basis of adult neurogenesis: from epigenetic, to transcriptional and metabolic control.

Chairperson

Aixa V. Morales and Helena Mira

OVERALL ABSTRACT

Code

SY03


The process of the formation of new neurons in the adult brain has intrigued and interested neuroscientists for many centuries, including the Spanish Nobel Prize eminence Santiago Ramón y Cajal. Although the process of adult neurogenesis was demonstrated by Altman and Das in a seminal paper in 1965, it has not been broadly accepted by the Neuroscience community until the 1990’s. Since then, there has been an amazing expansion of the field and the discovery of neural stem cells in the adult mammalian central nervous system has changed our contemporary perception of brain plasticity and function. The proposed Symposium will cover fundamental mechanisms that control adult brain neurogenesis in both main neurogenic adult niches (the subgranular zone of the dentate gyrus in the hippocampus and the subventricular-ventricular zone in the lateral ventricles). It will include talks that cover questions related to the maintenance of a quiescent neural stem population lifelong in the niches (S. Jessberger), the control of multipotency of neural stem cells (V. Taylor), the molecular control of proliferation and neuronal differentiation (V. Taylor, C. Lie) and also very recent aspects about the control of neurogenesis by epigenetic mechanisms (S. Ferrón) and by metabolic changes, including mitochondrial function (S. Jessberger and C. Lie). The program will be completed with two short talks selected from the abstracts submitted for oral presentations. For five decades now, research on adult neurogenesis and neural stem cells has been leading to an ever expanding field of discoveries that have influenced many domains of neuroscience and developmental biology. In the context of the SENC meeting, there are many research groups in fields closely related to the topics discussed in the proposed Symposium, apart from those directly working on adult neurogenesis. That is the case for groups working in developmental neurobiology, as the molecular mechanisms of adult neurogenesis to be discussed will be similar to those operating during developmental stages in others regions of the central nervous system such as the cortex, striatum or spinal cord. The other research groups interested in the topic will be those involved in programming neural stem cells and using them as therapeutic source for brain repair after damage and/or neurodegeneration, and those directly studying the endogenous potential of brain repair through adult neurogenesis stimulation. Finally, the alterations in adult neurogenesis have profound consequences in functional and behavioral aspects of the brain that will be also laterally brought by some of the speakers and that will be in the interest of groups working on hippocampal circuits and in olfaction. Thus, the proposed Symposium will explore neurogenesis from different perspectives, bringing new insights about the fundamental mechanisms that control normal brain development and that contribute to disease situations when this process is altered. We definitely believe that the Symposium will bring together scientists working on different aspects of neurogenesis and will successfully foster the exchange of ideas and facilitate novel collaborative projects and initiatives within the Spanish neuroscientific community.

Speakers

1. Prof. Dr. Sebastian Jessberger. Professor of Neurosciences and Managing Director of the Brain Research Institute, University of Zurich. 2. Prof. Verdon Taylor. Professor of Embryology and Stem Cell Biology in the Department of Biomedicine of the University of Basel. 3. Prof. Dr. Dieter Chichung Lie. Professor of Molecular Medicine in the Institute of Biochemistry of the 4. Dr. Sacri R. Ferron. Ramón y Cajal researcher at the Department of Cellular Biology of the University of Valencia

Contact:

Aixa V. Morales and Helena Mira. [email protected]; [email protected]

Session:

Symposium


SPEAKER 1

Code

SY03

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Abstracts: Symposia


Title:

Molecular and cellular mechanisms of stem cell quiescence in the mammalian brain

Speaker

Prof. Dr. Sebastian Jessberger


1. Moore DL, Pilz GA, Araúzo-Bravo MJ, Barral Y, Jessberger S. A mechanism for the segregation of age in mammalian neural stem cells. Science. 2015 Sep 18;349(6254):1334-8. 2.Braun SM, Pilz GA, Machado RA, Moss J, Becher B, Toni N, Jessberger S. Programming Hippocampal Neural Stem/Progenitor Cells into Oligodendrocytes Enhances Remyelination in the Adult Brain after Injury. Cell Rep. 2015 Jun 23;11(11):1679-85. 3.Knobloch M, Braun SM, Zurkirchen L, von Schoultz C, Zamboni N, Araúzo-Bravo MJ, Kovacs WJ, Karalay O, Suter U, Machado RA, Roccio M, Lutolf MP, Semenkovich CF, Jessberger S. Metabolic control of adult neural stem cell activity by Fasn-dependent lipogenesis. Nature. 2013 Jan 10;493(7431):226-30.

Session:

Symposium

Title:

Systems biology of telencephalon neurogenesis

Speaker

Prof. Verdon Taylor

SPEAKER 2

Code

SY03


1.Rolando C, Erni A, Grison A, Beattie R, Engler A, Gokhale PJ, Milo M, Wegleiter T, Jessberger S, Taylor V. Multipotency of Adult Hippocampal NSCs In Vivo Is Restricted by Drosha/NFIB. Cell Stem Cell. 2016 Nov 3;19(5):653-662. 2.Azim K, Hurtado-Chong A, Fischer B, Kumar N, Zweifel S, Taylor V, Raineteau O. Transcriptional Hallmarks of Heterogeneous Neural Stem Cell Niches of the Subventricular Zone. Stem Cells. 2015 Jul;33(7):2232-42. 3.Giachino C, Barz M, Tchorz JS, Tome M, Gassmann M, Bischofberger J, Bettler B, Taylor V. GABA suppresses neurogenesis in the adult hippocampus through GABAB receptors. Development. 2014 Jan;141(1):83-90.

Session:

Symposium

Title:

Role of Mitochondria and Autophagy in adult hippocampal neurogenesis

Speaker

Prof. Dr. Dieter Chichung Lie

SPEAKER 3

Code

SY03


1.Marschallinger J, Schäffner I, Klein B, Gelfert R, Rivera FJ, Illes S, Grassner L, Janssen M, Rotheneichner P, Schmuckermair C, Coras R, Boccazzi M, Chishty M, Lagler FB, Renic M, Bauer HC, Singewald N, Blümcke I, Bogdahn U, Couillard-Despres S, Lie DC, Abbracchio MP, Aigner L. Structural and functional rejuvenation of the aged brain by an approved anti-asthmatic drug. Nat Commun. 2015 Oct 27;6:8466. 2.Steib K, Schäffner I, Jagasia R, Ebert B, Lie DC. Mitochondria modify exercise-induced development of stem cell-derived neurons in the adult brain. J Neurosci. 2014 34(19):6624-33. 3.Mu L, Berti L, Masserdotti G, Covic M, Michaelidis TM, Doberauer K, Merz K, Rehfeld F, Haslinger A, Wegner M, Sock E, Lefebvre V, Couillard-Despres S, Aigner L, Berninger B, Lie DC. SoxC transcription factors are required for neuronal differentiation in adult hippocampal neurogenesis. J Neurosci. 2012 Feb 29;32(9):3067-80.

Session:

Symposium

Title:

Genomic imprinting and the regulation of postnatal neurogenesis

Speaker

Dr. Sacri R. Ferron


SPEAKER 4

Code

SY03

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Abstracts: Symposia


1.Ferrón SR, Radford EJ, Domingo-Muelas A, Kleine I, Ramme A, Gray D, Sandovici I, Constancia M, Ward A, Menheniott TR, Ferguson-Smith AC. Differential genomic imprinting regulates paracrine and autocrine roles of IGF2 in mouse adult neurogenesis. Nat Commun. 2015 Sep 15;6:8265. 2.Delgado AC, Ferrón SR, Vicente D, Porlan E, Perez-Villalba A, Trujillo CM, D'Ocón P, Fariñas I. Endothelial NT-3 delivered by vasculature and CSF promotes quiescence of subependymal neural stem cells through nitric oxide induction. Neuron. 2014 Aug 6;83(3):572-85. 3.Ferrón SR, Charalambous M, Radford E, McEwen K, Wildner H, Hind E, Morante-Redolat JM, Laborda J, Guillemot F, Bauer SR, Fariñas I, Ferguson-Smith AC. Postnatal loss of Dlk1 imprinting in stem cells and niche astrocytes regulates neurogenesis. Nature. 2011 Jul 20;475(7356):381-5.


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Symposium SY04. Adaptive coding of sensory signals for efficient behavioral performance


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Abstracts: Symposia


Session:

Symposium

Title:

Adaptive coding of sensory signals for efficient behavioral performance

Chairperson

Manuel Sánchez Malmierca y Livia de Hoz

OVERALL ABSTRACT

Code

SY04


This proposal is based on the assumption that the brain’s neuronal circuitry is organized as a highly predictive machine (Friston and colleagues), allowing us to foresee the consequences of stimulus patterns, such as the appearance of a car on the road or the next beat in the music. Behaviour becomes more efficient when we can predict a stimulus, in order to, for example, to prevent being run-over, or unconsciously tap to the music’s rhythm. This is the basis of the enormous flexibility underlying interactions with our physical and social environment. The auditory system is particularly important for predictive processing because it can detect signals coming from any direction within noisy backgrounds in a pre-attentive mode (e.g. during sleep). The auditory system can, thus, cope with the variability and redundancy in the auditory scene. This symposium will address the adaptive nature of the neural coding behind background characterization, novelty detection, and decision making in the auditory system of mammals and birds under different degrees of uncertainty. These questions will be addressed through four complementary approaches: 1) Adaptation of neural responses to common sounds and novelty detection; 2) Coding of sensory reliability by the neural pathway commanding sound localization; 3) Detection of sound periodicity for the establishment of rhythmic behaviour; and 4) Neural coding underlying the learning of regularities in complex environments. State-of-the-art approaches for neural recordings and behaviour as well as a broad range of species, including rodents, birds and primates, are discussed. The proposed talks cover different aspects of 'predictive processing'. Hugo Merchant and Livia de Hoz will discuss different aspects of the extraction of background statistics at the subcortical and cortical levels. Manuel S. Malmierca will talk about the mechanisms of change detection in the auditory domain. And, finally, Jose Luis Peña will discuss networks designed to weight orienting behaviors by sensory uncertainty and stimulus predictions. Filtering out non-relevant stimuli is an important but understudied aspect of cognition. Impairments in this process likely underlie the cognitive deficits observed in autism and schizophrenia. One model of study is stimulus-specific adaptation (SSA, a change-detection measure)). SSA has become a major field of research in recent years. It is believed to parallel Mismatch Negativity (MMN), a human EEG deflection. MMN has been positioned as a promising biomarker for the diagnosis of pathologies such as schizophrenia and autism spectrum disorders. Thus, SSA and other models presented here may become a handle for understanding neuronal dysfunction in such disorders. This symposium will, therefore, have a fundamental social impact in the near future. This symposium will also be relevant to a broad scientific community beyond the clinical perspective. For example, computational neuroscience is a maturing field and practitioners hunger for quantitative neurophysiology. The time is ripe for developing biophysical and network models that incorporate electrophysiological data at the cellular, synaptic and circuit levels guiding experiments assessing highlevel functions of the brain, such as predictive coding and probabilistic inference.

Speakers

1. Livia de Hoz. Max Planck Institute of Experimental Medicine, Göttingen, Germany. 2. Manuel S. Malmierca. Institute of Neuroscience of Castilla y León (INCYL). University of Salamanca 3. Hugo Merchant. Institute of Neurobiology. Autonomous University of Mexico (UNAM). Queretaro México 4. José Luis Peña. Dominick P. Purpura Department of Neuroscience. Albert Einstein College of Medicine. New York, USA.

Contact:

Manuel Sánchez Malmierca. [email protected]

Session:

Symposium

Title:

Subcortical processing of background statistics

Speaker

Livia de Hoz


SPEAKER 1

Code

SY04

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Abstracts: Symposia



1) Brzózka MM, Rossner MJ, de Hoz L. 2015. Tcf4 transgenic female mice display delayed adaptation in an auditory latent inhibition paradigm. European Archives of Psychiatry and Clinical Neuroscience. DOI 10.1007/s00406-015-0643-8. 2) de Hoz L and Nelken I. 2014. Frequency tuning in the behaving mouse: different bandwidths for discrimination and generalization. PLoS One, 9(3):e91676. 3) Hernandez V, Gehrt A, Reuter K, Jing Z, Marcus Jeschke M, Mendoza Schulz A, Hoch G, Bartels M, Vogt G, Garnham CW, Yawo H, Fukazawa Y, Augustine G, Bamberg E, Kügler S, Salditt T, de Hoz L, Strenzke N, Moser T. 2014. Optogenetic stimulation of the auditory pathway. Journal of Clinical Investigations, 124(3):1114-29.

Session:

Symposium

Title:

Functional mechanisms that mediate predictive coding in the auditory brain

Speaker

Manuel S. Malmierca

SPEAKER 2

Code

SY04


Nieto-Diego J, Malmierca MS. (2016) Topographic Distribution of Stimulus-Specific Adaptation across Auditory Cortical Fields in the Anesthetized Rat. PLoS Biol. 2016 Mar 7;14(3):e1002397. Ayala YA, Malmierca MS. (2015) Cholinergic Modulation of Stimulus-Specific Adaptation in the Inferior Colliculus. J Neurosci. 2015 Sep 2;35(35):12261-72. 3)Malmierca MS, Anderson LA, Antunes FM. (2015) The cortical modulation of stimulus-specific adaptation in the auditory midbrain and thalamus: a potential neuronal correlate for predictive coding. Front Syst Neurosci. 2015 Mar 9;9:19. doi: 10.3389/fnsys.2015.00019.

Session:

Symposium

Title:

Population state dynamics in medial premotor areas works as a master clock during different rhythmic tapping behaviors in the monkey

Speaker

Hugo Merchant

SPEAKER 3

Code

SY04


1)Crowe, D.A., Zarco, W., Bartolo, R., and Merchant, H. Dynamic representation of the temporal and sequential structure of rhythmic movements in the primate medial premotor cortex. J Neurosci (2014) 34(36): 11972-11983. 2)Merchant, H., Grahn, J., Trainer, L., Rohrmeier, M., and Fitch, TW. Finding the beat: A neural perspective across humans and non-human primates. Philos Trans R Soc Lond B Biol Sci. (2015) 370(1664): 186-202. 3) Merchant, H., Perez, O., Bartolo, R., Mendez JC., Mendoza, G., Gamez, J., Yc, K., Prado, L. (2015) Sensorimotor neural dynamics during isochronous tapping in the medial premotor cortex of the macaque.

Session:

Symposium

Title:

Emergence of an adaptive behavioral command for sound localization

Speaker

José Luis Peña

Abstract

F. Cazettes1, B.J. Fischer2, M.V. Beckert3, J.L. Pena3 1. Champalimaud Center for the Unknown, Lisbon, Portugal


SPEAKER 4

Code

SY04

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Abstracts: Symposia

2. Seattle University, Seattle, USA 3. Albert Einstein College of Medicine, New York, USA The brain can be viewed as a probabilistic estimator, where sensory statistics bias judgments. This question can be examined in sound-orienting behavior towards sound. Different species underestimate the direction of peripheral sound sources. We propose this centrality bias reflects the increased uncertainty of sensory cues about direction in the periphery. The neural pathway supporting the owl’s sound localization provides a means to examine how adaptive motor commands are implemented by integrating sensory information and uncertainty. We will show how sensory evidence about sound direction is weighted by its reliability in the owl’s auditory midbrain, to generate an adaptive motor command for head-orientation. We demonstrate that this coding emerges through convergence of upstream projections from a map of space onto premotor neurons that control behavior. We further show that manipulating the sensory input yields changes in both premotor responses and behavioral bias in a manner that predicted by statistical inference. Thus the topographic sensory representation of auditory space can be read out to adjust behavioral responses by statistics of the sensory input. Recent publications

1)Fischer BJ and Pena JL 2016 Optimal nonlinear cue integration for sound localization. J Comput Neurosci. 2016 Oct 6. [Epub ahead of print] 2)Cazettes F, Fischer BJ, Peña JL. 2016 Cue Reliability Represented in the Shape of Tuning Curves in the Owl's Sound Localization System. J Neurosci. 2016 Feb 17;36(7):2101-10. doi: 10.1523/JNEUROSCI.3753-15.2016. 3)Cazettes F, Fischer BJ, Pena JL. 2014 Spatial cue reliability drives frequency tuning in the barn Owl's midbrain. Elife. 2014 Dec 22;3:e04854. doi: 10.7554/eLife.04854


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Symposium SY05. Advanced MRI contrasts to investigate brain inflammation and degeneration


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Abstracts: Symposia

Session:

Symposium

Title:

Advanced MRI contrasts to investigate brain inflammation and degeneration

Chairperson

Dr Silvia De Santis

OVERALL ABSTRACT

Code

SY05


The symposium we propose will focus on innovative non-invasive MRI approaches applied to the theme of neuroinflammation and degeneration. Inflammation, demyelination and axon degeneration are interplaying phenomena involved in the brain’s reaction to a variety of cues including infection, traumatic injury, toxic metabolites, or autoimmunity. Recently, these physiological processes have become a hot topic in brain research, due to their involvement in the pathogenesis of several neurodegenerative and psychiatric disorders. For example, they have all been associated with multiple sclerosis, Alzheimer’s and Parkinson’s. More recent examples demonstrate involvement of the brain immune system in social behavior, and even in the regulation of infection at mucosal barriers and gut defense. Magnetic Resonance Imaging (MRI) offers unrivaled opportunities to look at brain tissue in-vivo and non-invasively. In the last few years, there has been an effort in the MRI community to increase the specificity of the contrast to different tissue structural and functional subunits by proposing innovative acquisition and analysis strategies, and multimodal approaches have become more and more popular. In this context, advanced multimodal MRI can offer unmatched non-invasive possibilities to look into the issue of brain inflammation and degeneration by dissecting its different aspects. This symposium will cover from the last advances on MRI methods and analytical tools to investigate neuroinflamatory and neurodegenerative processes, to applications in animal models, clinical studies and multimodal investigations on the biological underpinning of MRI findings. The proposed symposium is of general interest for neuroscientist in most research fields. MRI imaging is a non-invasive technique that can offer complementary, whole brain information on different structural and functional aspects of interest, and can be extremely useful when paired with other invasive techniques. The non-expert audience attending the symposium will have access to the last developments in the field and the information that can be gathered by using the presented approaches, both in animals and humans, as well as the requirements in terms of implementation. Therefore, for a general audience it will bring new knowledge and possibilities of potential value in their respective research fields and specific research projects. For experts in the topic of neuroinflammation and neurodegeneration, this will represent an exceptional opportunity to confront their own approaches and results with those obtained with a valuable and versatile technique like MRI, engaging in fruitful discussions. For MRI experts, this symposium is an important opportunity to interact with some world-class figures in the field of advanced MRI like Prof. Yaniv Assaf, and exchange their own experiences and viewpoints. In addition, this symposium will represent a good opportunity to increase the presence of brain neuroimaging in humans and animal models in the SENC meetings.

Speakers

1. 2. 3. 4.

Prof. Yaniv Assaf. Tel Aviv University, Tel Aviv, Israel Dr. Silvia De Santis. Instituto de Neurociencias, CSIC – UMH, San Juan de Alicante, Spain Prof. Nicola Toschi. Tor Vergata University, Roma, Italy Dr. Claudia Metzler-Baddeley. CUBRIC, Cardiff University, Cardiff, UK

Contact:

Dr Silvia De Santis. [email protected]

Session:

Symposium

Title:

New modeling and experimental framework to characterize water diffusion in human brain

Speaker

Prof. Yaniv Assaf

SPEAKER 1

Code

SY05


1. Barazany, D., Basser, P.J., Assaf, Y. In vivo measurement of axon diameter distribution in the corpus callosum of rat brain. Brain 2009;52:965 2. Assaf, Y., Ben-Bashat, D., Chapman, J., (...), Graif, M., Cohen, Y. High b-value q-space analyzed


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Abstracts: Symposia


diffusion-weighted MRI: Application to multiple sclerosis. Magn Res Med 2002;47:115 3. Horowitz, A., Barazany, D., Tavor, I., (...), Yovel, G., Assaf, Y. In vivo correlation between axon diameter and conduction velocity in the human brain. Brain Struct Funct 2015;220:1777

Session:

Symposium

Title:

Advanced translational diffusion mri - an early window on neurodegenerative and neuroinflammatory diseases

Speaker

Dr. Silvia De Santis

Abstract

S. De Santis 1, L. Pérez-Cervera 1, S. Pfarr 2, G. Weil3, S. Vollstädt-Klein3, R. Ciccocioppo 3, N. Toschi 4, W. H. Sommer 2,3, S. Canals 1

SPEAKER 2

Code

SY05

1. Instituto de Neurociencias de Alicante (CSIC-UMH), Sant Joan d'Alacant, Alicante, Spain 2. Departments of Psychopharmacology and 3Addiction Medicine, Central Institute of Mental Health, University of Heidelberg, Mannheim, Germany 4. School of Pharmacy University of Camerino, Camerino, Italy 5. Department of Biomedicine and Prevention, University of Rome Tor Vergata, Rome, Italy Objectives: Diffusion tensor imaging (DTI), by measuring water diffusivity in brain, provides indices of microstructural integrity highly sensitive to abnormalities occurring in several neurological conditions, but lacks specificity to the underlying microstructure. Recently, new frameworks have been introduced to increase specificity to different tissue sub-compartments and unmask subtle disease-related microstructural changes. Here, we show that advanced approaches like the Composite Hindered and Restricted Model of Diffusion (CHARMED) and AxCaliber provide additional information on pathological brain state in 1) early stage multiple sclerosis on human, compared to healthy controls; and 2) two models of alcohol addiction in rats. We also show that 3) the animal results aid the interpretation of a large human DTI study targeting detoxication from alcohol. Methods: CHARMED/AxCaliber comprise diffusion-weighted acquisitions for different weightings and directions, acquired on MRI scanners operating at 3T (human) and 7T (animal). Data analysis was done using in-house software written in Matlab. Conventional DTI and CHARMED/AxCaliber maps were obtained and fed into the Tract Based-Spatial Statistics pipeline to look for significant differences between cohorts, accounting for age/gender/multiple comparisons when relevant. Results: 1) In the early-stage MS patients, we detect a reduction of axonal density in white matter, which is invisible to conventional DTI; 2) in both rat models of alcohol consumption we find significant patterns of changes for different microstructural properties, both in the acute alcohol consumption phase and during abstinence, suggesting that the microstructural modifications caused by alcohol usage are only partially reversible. 3) These results aid the interpretation of the DTI changes observed in alcohol dependent patients after about two weeks of abstinence, compared to a cohort of healthy controls. Conclusions: Advanced diffusion MRI increases specificity to changes in brain sub-compartments, offering new information into the pathophysiology of inflammatory and degenerative disease. Recent publications

1. De Santis, S., Drakesmith, M., Bells, S., Assaf, Y., Jones, D.K. Why diffusion tensor MRI does well only some of the time: Variance and covariance of white matter tissue microstructure attributes in the living human brain. NeuroImage 2014;89:35 2. De Santis, S., Assaf, Y., Jeurissen, B., Jones, D.K., Roebroeck, A. T1 relaxometry of crossing fibres in the human brain. NeuroImage 2016;141:133 3. De Santis, S., Jones, D.K., Roebroeck, A. Including diffusion time dependence in the extra-axonal space improves in vivo estimates of axonal diameter and density in human white matter. NeuroImage 2016;130:91

Session:

Symposium

Title:

Multimodal MRI approaches to neurodegenerative diseases

Speaker

Prof. Nicola Toschi

SPEAKER 3

Code

SY05

Abstract www.congreso-senc.com

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Abstracts: Symposia


Recent publications

1. Diciotti, S., Ciulli, S., Ginestroni, A., (...), Mascalchi, M., Toschi, N. Multimodal MRI classification in vascular mild cognitive impairment. Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society 2015;7319340:4278-4281 2. Tessa, C., Lucetti, C., Giannelli, M., (...), Mascalchi, M., Toschi, N. Progression of brain atrophy in the early stages of Parkinson's disease: A longitudinal tensor-based morphometry study in de novo patients without cognitive impairment. Human Brain Mapping 2014;35:3932 3. Mascalchi, M., Toschi, N., Ginestroni, A., (...), Soricelli, A., Diciotti, S. Gender, age-related, and regional differences of the magnetization transfer ratio of the cortical and subcortical brain gray matter. J Magn Res Im 2014;40:360

Session:

Symposium

Title:

Cross-sectional differences in myelin and axonal metrics in Huntington's disease

Speaker

Dr. Claudia Metzler-Baddeley

SPEAKER 4

Code

SY05


1. Christiansen, K., Aggleton, J.P., Parker, G.D., (...), Vann, S.D., Metzler-Baddeley, C. The status of the precommissural and postcommissural fornix in normal ageing and mild cognitive impairment: An MRI tractography study NeuroImage 2016;130:35 2. Metzler-Baddeley, C., Jones, D.K., Steventon, J., (...), Aggleton, J.P., O'Sullivan, M.J. Cingulum microstructure predicts cognitive control in older age and mild cognitive impairment. J Neuroscience 2012;32:17612 3. Metzler-Baddeley, C., Cantera, J., Coulthard, E., (...), Jones, D.K., Baddeley, R.J. Improved executive function and callosal white matter microstructure after rhythm exercise in Huntington'S Disease. Journal of Huntington's Disease 2014;3:273


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Symposium SY06. Schwann cells in nerve function and repair


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Abstracts: Symposia


Session:

Symposium

Title:

Schwann cells in nerve function and repair

Chairperson

Hugo Cabedo Martí

OVERALL ABSTRACT

Code

SY06


Schwann cells form myelin, which is essential for axonal insulation and saltatory conduction of action potentials. Indeed myelin defects underlie inherited and acquired peripheral neuropathies (such as Charcot Marie Tooth and Guillain Barré syndrome) leading to motor and sensory disabilities. Schwann cells are also pivotal for nerve repair after injury. It is thus necessary to explore Schwann cell biology to understand these diseases and design therapeutic strategies to improve nerve function and regeneration. In this symposium we will put together a group of Schwann cell researchers, based in our country and abroad, to discuss and exchange the most recent data on the role of Schwann cells in myelin development and nerve repair. The speakers of this symposium have very well-established long-term track record of research on Schwann cell biology and pathology, neuroregeneration and demyelinating diseases. They have also considerable complementary expertise in their research approaches and methodologies in the Schwann cell and myelin fields. Speakers include Peter Brophy, a highly reputed British scientist, Ashwin Woodhoo a young Schwann cell researcher recently established in our country, Jose A. GomezSanchez, a Spanish postdoctoral researcher working in Kristian Jessen’s lab (a UK-based reference laboratory on Schwann cell biology and pathology) and myself (an established researcher at the Institute of Neuroscience in Alicante). We believe that if the proposed symposium is selected, it will help to attract a new generation of young Spanish researchers into the filed of glial biology, one of the very important strands of modern Neuroscience. Schwann cells in the PNS and oligodendrocytes in the CNS form myelin. Although with minor structural differences, both PNS and CNS myelin have evolved to fulfill similar roles in vertebrates, such as promoting saltatory nerve conduction and providing trophic support to axons. Therefore myelin is central for the proper function of every structure in the vertebrate nervous system. To learn how Schwann cells form myelin and promote peripheral nerve regeneration can be thus pivotal not only to understand peripheral nerve physiology but also to get new insights into CNS function. Importantly, It could also help to unveil what distinguishes CNS regeneration and makes it dramatically inefficient when compared with PNS regeneration. We believe that this information will be of general interest for the members of the Spanish Society for Neuroscience.

Speakers

1. 2. 3. 4.

Peter Brophy. Centre for Neuroregeneration University of Edinburgh Ashwin Woodhoo. : CIC bioGUNE (Bilbao, Spain) Jose A. Gomez-Sanchez. University College London Hugo Cabedo. Instituto de Neurociencias UMH-CSIC and ISABIAL-FISABIO

Contact:

Hugo Cabedo Martí. [email protected]

Session:

Symposium

Title:

Insights from Peripheral Demyelinating Neuropathy into the Assembly and Function of the Node of Ranvier

Speaker

Peter Brophy

SPEAKER 1

Code

SY06


1. 2.

3.


Wu, L.M.N., A. Williams, A. Delaney, D.L. Sherman, and P.J. Brophy (2012). Increasing internodal distance in myelinated nerves accelerates nerve conduction to a Flat Maximum. Current Biology 22: 1957-1961. Zhang, A., A. Desmazieres, B. Zonta, S. Melrose, G. Campbell, D. Mahad, Q. Li, D.L. Sherman, R. Reynolds and P.J. Brophy1 (2015). Neurofascin 140 is an embryonic neuronal Neurofascin isoform that promotes the assembly of the node of Ranvier. J. Neurosci. 5: 22462254. Noseda, R., M. Guerrero-Valero, V. Alberizzi, S.C. Previtali, D.L. Sherman, M. Palmisano, R.L. Huganir, K.A. Nave, A. Cuenda, M.L. Feltri, P.J. Brophy, and A. Bolino. (2016) Kif13b Regulates PNS and CNS Myelination through the Dlg1 Scaffold. PLoS Biology 14, e1002440. - 32 -

Abstracts: Symposia


Session:

Symposium

Title:

Transcriptional control of gene expression in Schwann cell myelination and pathology

Speaker

Ashwin Woodhoo

Abstract

M. Iruarrizaga-Lejarreta1, E. Perez-Andres1, M. Palomo1, D. Medrano1, M. Varela-Rey1, A. Woodhoo1, 2. 1. CIC bioGUNE, Technology Park of Bizkaia, 48160 Derio, Bizkaia, Spain 2. Ikerbasque, Basque Foundation for Science, 48013 Bilbao, Bizkaia, Spain.

SPEAKER 2

Code

SY06

Neurofibromatosis type 1 (NF1) is one of the most common genetic disorders among humans, affecting 1:3500 individuals worldwide. The hallmark of NF1 is the development of multiple benign peripheral nerve sheath tumours known as dermal and plexiform neurofibromas. Approximately 10% of plexiform neurofibromas undergo malignant transformation into malignant peripheral nerve sheath tumors (MPNSTs), aggressive and highly metastatic soft tissue sarcomas that are essentially incurable. Schwann cells are the crucial pathogenic cell type in NF1. The RNA-binding protein (RBP) HuR is aberrantly expressed in several types of cancers, in which it regulates the expression of several cancer-related proteins. We observed that HuR expression was significantly increased in NF and MPNST samples compared to normal nerves by IHC, qPCR and WB analysis, and found a strong correlation between HuR expression and degree of malignancy. RIP-CHIP analysis showed that the number of mRNAs bound to HuR increased as malignancy progresses. Amongst them, several ones with well-defined roles in oncogenesis were identified. Lentiviral-mediated HuR silencing in vitro and in vivo blocked both MPNST growth and metastasis. This work points to a key master regulatory role of HuR in controlling gene expression patterns in MPNST, and identify HuR as a possible therapeutic target for these tumours. Recent publications

1.

2.

3.

Gomez-Sanchez, J.A, L. Carty, M. Iruarrizaga-Lejarreta, M. Palomo, M. Varela-Rey, M. Griffith, J. Hantke, N. Macias, M. Azkargorta, I. Aurrekoetxea, H.B.J. Jefferies, P. Aspichueta, F. Elortza, A.M. Aransay, M.L. Martínez Chantar, F. Baas, J.M. Mato, R. Mirsky, A. Woodhoo* and K.R. Jessen*. 2015. Schwann cell autophagy, myelinophagy, clears myelin. Journal of Cell Biology 210: 153-168. * joint senior and corresponding authors Varela-Rey, M., M. Iruarrizaga-Lejarreta, J.J. Lozano, A.M. Aransay, A.F. Fernandez, J.L. Lavin, D. Mosen-Ansorena, M. Berdasco, M. Turmaine, Z. Luka, C. Wagner, S.C. Lu, M. Esteller, R. Mirsky, K.R. Jessen, M.F. Fraga, M.L. Martinez-Chantar, J.M. Mato, and A. Woodhoo*. 2014. S- adenosylmethionine levels regulate the schwann cell DNA methylome. Neuron. 81:1024-1039. Iruarrizaga-Lejarreta, M., M. Varela-Rey, J.J. Lozano, D. Fernandez-Ramos, N. RodriguezEzpeleta, N. Embade, S.C. Lu, P.M. van der Kraan, E.N. Blaney Davidson, M. Gorospe, R. Mirsky, K.R. Jessen, A.M. Aransay, J.M. Mato, M.L. Martinez-Chantar, and A. Woodhoo*. 2012. The RNA-binding protein human antigen R controls global changes in gene expression during Schwann cell development. The Journal of Neuroscience. 32:4944-4958.

Session:

Symposium

Title:

Myelin clearance and autophagy after peripheral nerve injury

Speaker

Jose A. Gomez-Sanchez

SPEAKER 3

Code

SY06


1.

Gomez-Sanchez, J.A, L. Carty, M. Iruarrizaga-Lejarreta, M. Palomo, M. Varela-Rey, M. Griffith, J. Hantke, N. Macias, M. Azkargorta, I. Aurrekoetxea, H.B.J. Jefferies, P. Aspichueta, F. Elortza, A.M. Aransay, M.L. Martínez Chantar, F. Baas, J.M. Mato, R. Mirsky, A. Woodhoo and K.R. Jessen. 2015. Schwann cell autophagy, myelinophagy, clears myelin. Journal of Cell Biology 210: 153-168. Doi: 10.1083/jcb.201503019

2.

Epigenetic induction of the Ink4a/Arf locus prevents Schwann cell overproliferation during nerve regeneration and after tumorigenic challenge. Gomez-Sanchez JA, Gomis-Coloma C,


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Abstracts: Symposia


Morenilla- Palao C, Peiro G, Serra E, Serrano M, Cabedo H. Brain. 2013 Jul;136(Pt 7):2262-78. doi: 10.1093/brain/awt130. 3.

L1CAM binds ErbB receptors through Ig-like domains coupling cell adhesion and neuregulin signalling. Donier E, Gomez-Sanchez JA, Grijota-Martinez C, Lakomá J, Baars S, GarciaAlonso L, Cabedo H. PLoS One. 2012;7(7):e40674. doi: 10.1371/journal.pone.0040674.

Session:

Symposium

Title:

Class IIa HDACs link cAMP signaling to Schwann cell phenotype

Speaker

Hugo Cabedo

SPEAKER 4

Code

SY06


1.

Epigenetic induction of the Ink4a/Arf locus prevents Schwann cell overproliferation during nerve regeneration and after tumorigenic challenge. Gomez-Sanchez JA, Gomis-Coloma C, Morenilla- Palao C, Peiro G, Serra E, Serrano M, Cabedo H. Brain. 2013 Jul;136(Pt 7):2262-78. doi: 10.1093/brain/awt130.

2.

L1CAM binds ErbB receptors through Ig-like domains coupling cell adhesion and neuregulin signalling. Donier E, Gomez-Sanchez JA, Grijota-Martinez C, Lakomá J, Baars S, GarciaAlonso L, Cabedo H. PLoS One. 2012;7(7):e40674. doi: 10.1371/journal.pone.0040674.

3.

Sustained axon-glial signaling induces Schwann cell hyperproliferation, Remak bundle myelination, and tumorigenesis. Gomez-Sanchez JA, Lopez de Armentia M, Lujan R, Kessaris N, Richardson WD, Cabedo H. J Neurosci. 2009 Sep 9;29(36):11304-15. doi: 10.1523/JNEUROSCI.1753-09.2009.


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Symposium SY07. In vivo electrophysiology and imaging to unveil neuronal network functioning


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Abstracts: Symposia


Session:

Symposium

Title:

In vivo electrophysiology and imaging to unveil neuronal network functioning

Chairperson

Rafael Fernández Chacón

OVERALL ABSTRACT

Code

SY07


The study of functional dynamics of neuronal circuitry in intact brains of living animals is a major challenge in contemporary Neuroscience. There is an increasing interest to perform large-scale measurements of the activity of neuronal populations. To solve this issue, the state-of-the-art electrophysiological recordings in the brain of freely behaving or anesthetized animals allow researchers to simultaneously examine local field potentials (LFPs) from populations of neurons and action potentials from individual cells. Chronically implanted electrode arrays (tetrods) allow for brain recordings to last over periods of several weeks. This technique insures high stability and fidelity of neural recordings as the animal is challenged with different behavioral tasks. On the other hand, in-vivo two-photon calcium imaging through a cranial window is the only method that allows one to record the activity of neuronal population with single-cell resolution chronically. Recent improvements in genetically encoded calcium indicators (GECIs), combined with the expansion of fast resonant twophoton imaging of freely moving animals allow to stablish correlations between cortical neural activity and behavior. Along this symposium we will discuss how novel electrophysiological and imaging techniques, combined with mouse genetics, are helping neuroscientists to unveil the local network circuitry. It is obvious that a deep understanding of the brain circuitry requires to focus on living animals. Spain has an excellent tradition in the field of in vivo electrophysiology, however, at the moment there are only very few groups starting to use multiphoton microscopy to investigate brain function. On the other hand, multiphoton microscopy is a very well stablished approach in neuroscience institutes in Europe and the U.S.A. We really believe that this symposium is a very exciting opportunity to bring together excellent stablished electrophysiologists with junior investigators that have acquired highly valuable experience in multiphoton microscopy in internationally recognized laboratories and are now introducing these techniques in national laboratories. Undoubtedly, the proposed talks will throw light to common scientific questions and will foster rich and provoking discussions based on two clearly complementary methodological approaches.

Speakers

1. 2. 3. 4.

Liset Menéndez de la Prida. Laboratorio de Circuitos Neuronales. Instituto Cajal-CSIC. Francisco J Martini. Laboratory of cellular and molecular mechanisms of brain wiring. Instituto de Neurociencias de Alicante. Juan de los Reyes Aguilar. Grupo de Neurofisiología Experimental. Hospital Nacional de Parapléjicos. Servicio de Salud de Castilla-La Mancha (SESCAM), Toledo. Pablo García-Junco Clemente. Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío-CSIC y Universidad de Sevilla.

Contact:

Rafael Fernández Chacón. [email protected]

Session:

Symposium

Title:

Deep-superficial organization of hippocampal oscillations

Speaker

Liset Menéndez de la Prida

SPEAKER 1

Code

SY07


1.

2.

3. www.congreso-senc.com

1.Valero M., Cid E., Averkin RG, Aguilar J, Sanchez-Aguilera A, Viney TJ, GomezDominguez D, Bellistri E, Menendez de la Prida L. Determinants of different deep and superficial CA1 pyramidal cell dynamics during sharp-wave ripples. Nature Neuroscience 18, 1281–1290 (2015). 2.Laurent F, Brotons-Mas JR, Cid E, Lopez-Pigozzi D, Valero M, Gal B, Menendez de la Prida L Proximodistal structure of theta coordination in the dorsal hippocampus of epileptic rats. J Neuroscience. 35(11): 4760-4775 (2015) Aivar P, Valero M, Bellistri E, Menendez de la Prida L. Extracellular calcium controls the - 36 -

Abstracts: Symposia


expression of two different forms of ripple-like hippocampal oscillations. J Neuroscience. 34(8): 2989-3004 (2014)

Session:

Symposium

Title:

Spatial distribution of neuronal selectivity to whisker motion patterns in mouse barrel cortex.

Speaker

Francisco J Martini

Abstract

.

Recent publications

1. 2. 3. 4.

SPEAKER 2

Code

SY07

Martini, F. J., Molano, M., Maravall, M. Interspersed distribution of selectivity to kinematic stimulus features in supragranular layers of mouse barrel cortex. Cerebral Cortex, Under revision. Ferrati, G., Martini, F. J. & Maravall, M. Presynaptic Adenosine Receptor-Mediated Regulation of Diverse Thalamocortical Short-Term Plasticity in the Mouse Whisker Pathway. Front Neural Circuits 10, 9 (2016). Roth, M. M. et al. Thalamic nuclei convey diverse contextual information to layer 1 of visual cortex. Nat Neurosci (2015). Díaz-Quesada, M.*, Martini, F. J.*, Ferrati, G., Bureau, I. & Maravall, M. Diverse thalamocortical short-term plasticity elicited by ongoing stimulation. Journal of Neuroscience 34, 515–526 (2014)

Session:

Symposium

Title:

The Neurophysiological Puzzle of the Cortical plasticity after a Spinal Cord Injury

Speaker

Juan de los Reyes Aguilar

SPEAKER 3

Code

SY07


1. 2. 3.

Humanes-Valera D, Foffani G, Alonso-Calviño E, Fenández-López E, Aguilar J. (2016). Dual cortical plasticity after spinal cord injury. Cerebral Cortex Epub ahead of print.doi: 10.1093/cercor/bhw142. Alonso-Calviño E, Martínez-Camero I, Fernández-López E, Humanes-Valera D, Foffani G, Aguilar J. (2016). Increased responses in the somatosensory thalamus immediately after spinal cord injury Aguilar J, Humanes-Valera D, Alonso-Calviño E, Yagüe JG, Moxon K, Oliviero A, Foffani G. (2010). Spinal cord injury immediately changes the state of the brain. Journal of Neuroscience 30:7528- 7537

Session:

Symposium

Title:

Connectivity of cortical microcircuitry revealed by large-scale 2-photon imaging.

Speaker

Pablo García-Junco Clemente

Abstract

P. García-Junco Clemente 1,2, T. Ikrar3, E. Tring1, X. Xu3, D.L. Ringach1,4 and J.T. Trachtenberg1. 1. Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles, California, USA. 2. Instituto de Biomedicina de Sevilla, IBiS, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla and Departamento de Fisiología Médica y Biofísica, Universidad de Sevilla, and CIBERNED, Seville, Spain. 3. Department of Anatomy &Neurobiology, University of California, Irvine, California, USA. 4. Department of Psychology, University of California, Los Angeles, California, USA.

SPEAKER 4

Code

SY07

Cortical processing engages the interaction between excitatory and inhibitory neurons. Over the last few years, synaptic inhibition has been shown as a key player to head spontaneous and sensory-driven activity in the cerebral cortex, and it’s generated by interneurons reciprocally connected to other cortical www.congreso-senc.com

- 37 -


Abstracts: Symposia

neurons. Interneurons expressing parvalbumin (PV), somatostatin (SOM) and vasoactive intestinal peptide (VIP) are the three largest and non-overlapping classes of interneurons in the mouse cortex. In vitro studies have shown cortical interactions between these groups of interneurons and their excitatory partners, but the functional meaning of the connections are poorly understood. An important question in systems neuroscience is how behavioral state modulates the processing of sensory signals. To get a better understanding about it, we employ a novel approach based on resonant scanning 2-photon imaging of large populations of identified cortical neurons in frontal cortex of behaving mice. GCAMP6 calcium sensors were used to image activity of excitatory and inhibitory neurons, using cell type specific CREdriver lines that also expressed a red fluorescent protein. Because neural responses are modulated by brain state, which changes with arousal, attention, and behavior, we correlate activity pattern of local circuits with brain state through monitoring of pupil and ball. Our data identify a novel dual role of VIP interneurons to modulate the gain of excitatory neurons. During arousal, pyramidal neurons receive both indirect VIP SOM cell-mediated disinhibition and direct VIP cell-mediated inhibition. An expected outcome from this circuitry is that variability in the net balance of inhibition and disinhibition generates a heterogeneous response of excitatory neurons, some of which are enhanced during arousal as others are suppressed. The impact of the PV cells in the local circuitry is still under study, but our findings suggest that PV cells are functionally heterogeneous and they comprise at least two stable and distinct subnetworks. Recent publications

1. 2. 3.


Garcia-Junco-Clemente P, Ikrar T, Tring E, Xu X., Ringach DL and Trachtenberg JT. An inhibitory pull-push circuit controlled by arousal (Nature Neuroscience, in Press) Ringach DL, Mineault PJ, Tring E, Olivas ND, Garcia-Junco-Clemente P, Trachtenberg JT. Spatial clustering of tuning in mouse primary visual cortex. Nat Commun. 2016 Aug 2;7:12270. Garcia-Junco-Clemente P, Chow DK, Tring E, Lazaro MT, Trachtenberg JT, Golshani P. Overexpression of calcium-activated potassium channels underlies cortical dysfunction in a model of PTEN-associated autism. Proc Natl Acad Sci U S A. 2013 Nov 5;110(45):18297-302

- 38 -

Symposium SY08. Neural basis of normal and pathological oscillations


- 39 -

Abstracts: Symposia


Session:

Symposium

Title:

Neural basis of normal and pathological oscillations

Chairperson

Manuel Valero

OVERALL ABSTRACT

Code

SY08


Brain oscillations support and organize information flow across neural circuits. Despite the close relationship between major brain outcomes – as perception, memory and behavior - and brain oscillations, their association with the temporal structure of the neuronal activity remains poorly understood. Driven by current technological and analytical advances, understanding brain oscillations is today more appealing than ever. Hence, recent studies are increasingly pointed out how alterations of brain rhythms underlie the etiology and symptoms of a great plethora of brain diseases, defining a common substrate across different disorders: rhythmopathies. This symposium will present emerging work from outstanding laboratories in the field of neural oscillations. Talks will range from the oscillatory mechanisms that support behavior and memory encoding, the role of specific neuronal subtypes in network activity and its disruption in schizophrenia, Down syndrome and epilepsy. A common feature is the use of most cutting-edge techniques, such as large-scale multichannel recordings, opto/chemogenetic perturbations and single-cell recording in behaving rodents, highlighting the value of the state-of-the-art methods to understand the brain and to identify the processes leading to pathology. We believe that the proposed symposium will be of broad interest for SENC members. On one hand, we will cover network and neuronal mechanisms of memory and timing in hippocampal and cortical circuits which are of interest for behavioral and systems neuroscientists. How neuronal assemblies of pyramidal cells and interneurons are coordinated across brain structures to control behavior is a central question. On the other hand, we will review recent results in the cellular basis of diseases such as epilepsy, Schizophrenia or Down syndrome, emphasizing the role of genetically or inmunochemically defined cellular subclasses. The role of neuronal subtypes in organizing network activity and their failure in mental disorders is an emerging topic calling for new and more specific diagnostic tools. Finally, the experimental and analytical methods used have applicability in many different areas of Neuroscience. Those methods have been developed in rodents but are progressively being applied to other species and human patients. We will also illustrate how this application to the clinic has the potential to offer early diagnosis and highly specific pharmacological targets in multiple brain disorders thus reinforcing our translational appeal.

Speakers

1. 2. 3. 4.

Antonio Fernández-Ruiz. New York University - Neuroscience Institute, New York, USA Jorge R Brotons-Mas. Instituto de Neurociencias de Alicante, Alicante, Spain Manuel Valero. Instituto Cajal - CSIC, Madrid, Spain Marta Carus-Cadavieco. Leibniz Institute for Molecular Pharmacology (FMP)/ NeuroCure Cluster of Excellence, Berlin, Germany

Contact:

Manuel Valero. [email protected]

Session:

Symposium

Title:

Oscillatory mechanisms of temporal and spatial coding in cortico-hippocampal circuits.

Speaker

Antonio Fernández-Ruiz

SPEAKER 1

Code

SY08


1. 2. 3.


Schomburg EW*, Fernández-Ruiz A*, Berényi A, Mizuseki K, Anastassiou CA, Koch C, Buzsáki G. (2014). Theta phase segregation of input-specific gamma patterns in entorhinalhippocampal networks. Neuron. 84:470-485. (* equal contribution) Oliva A, Fernández-Ruiz A, Buzsáki G, Berényi A. Role of hippocmapal CA2 region in triggering sharp-wave ripples. Neuron 91, 1342-1355. Fernandez-Ruiz A, Muñoz S, Sancho M, Makarov VA, Herreras O. (2013) Cytoarchitectonic and dynamic origins of giant positive LFPs in the Dentate Gyrus. J Neurosci 33:15518-15532

- 40 -

Abstracts: Symposia


Session:

Symposium

Title:

Abnormal wiring of different subpopulations of interneurons during development generates specific oscillatory and cognitive impairments

Speaker

Jorge R Brotons-Mas

SPEAKER 2

Code

SY08


1. 2.

3.

Del Pino I*, Brotons-Mas J* , Marques-Smith A, Marín A, Rico B. "Abnormal wiring of CCK+VGlut3+ interneurons disrupt hippocampal activity and spatial representation". Submitted to Nat Neurosc Del Pino I*, García-Frigola C*, Dehorter N+, Brotons-Mas JR+, Alvarez-Salvado E, Martínez de Lagrán M, Ciceri G, Gabaldón MV, Moratal D, Dierssen M, Canals S, Marín O, Rico B. (2013) "Erbb4 deletion from fast-spiking interneurons causes schizophrenia-like phenotypes". Neuron. Sep 18;79(6):1152-68. Diego Lopez-Pigozzi *, François Laurent *, Jorge R Brotons-Mas *, Mario Valderrama, Manuel Valero, Ivan Fernandez-Lamo, Elena Cid, Daniel Gomez-Dominguez, Beatriz Gal, Liset Menendez de la Prida (2016) “Altered oscillatory dynamics of CA1 parvalbumin-basket cells during theta-gamma rhythmopathies of temporal lobe epilepsy”. ENeuro.

Session:

Symposium

Title:

Cell-type specific contribution to hippocampal rhythmopathies in the epileptic brain

Speaker

Manuel Valero

SPEAKER 3

Code

SY08


1.

2. 3.

Valero M, Cid E, Averkin RG, Aguilar J, Sanchez-Aguilera A, Viney TJ, Gomez-Dominguez D, Bellistri E, Menendez de la Prida L (2015). Determinants of different deep and superficial CA1 pyramidal cell dynamics during sharp-wave ripples. Nature Neuroscience 18, 1281–1290 (2015). Laurent, Brotons-Mas JR, Cid E, Lopez-Pigozzi D, Valero M, Gal B, Menendez de la Prida L (2015). Proximodistal structure of theta coordination in the dorsal hippocampus of epileptic rats. J Neuroscience. 35(11): 4760-4775. Aivar P, Valero M, Bellistri E, Menendez de la Prida L (2014). Extracellular calcium controls the expression of two different forms of ripple-like hippocampal oscillations. J Neuroscience. 34(8): 2989-3004.

Session:

Symposium

Title:

Gamma oscillations organize top-down signalling to hypothalamus and enable food seeking

Speaker

Marta Carus-Cadavieco

SPEAKER 4

Code

SY08


1.

2. 3.


Carus-Cadavieco M*, Gorbati M*, Ye L, Bender F, van der Veldt S, Kosse C, Börgers C, Lee SY, Ramakrishnan C, Hu Y, Denisova N, Ramm F, Volitaki E, Burdakov D, Deisseroth K, Ponomarenko A*§, Korotkova T*§ (2017). Gamma oscillations organize top-down signaling to hypothalamus and enable food seeking. Nature. 542(7640):232-236. (* equal contribution). Gutierrez Herrera C, Carus Cadavieco M, Jego S, Ponomarenko A, Korotkova A and Adamantidis A. (2016). Hypothalamic feed-forward inhibition of thalamocortical network controls arousal and consciousness. Nature Neuroscience. 19(2):290-298. Bender F*, Gorbati M*, Carus Cadavieco M, Denisova N, Gao X, Holman C, Korotkova T*§, Ponomarenko A*§ (2015). Theta oscillations regulate the speed of locomotion via a hippocampus to lateral septum pathway. Nature Communications. Oct 12; 6:8521. (* equal contribution). - 41 -



Abstracts: Symposia

- 42 -

Symposium SY09. Basal Ganglia Circuits in Health and Disease


- 43 -

Abstracts: Symposia


Session:

Symposium

Title:

Basal Ganglia Circuits in Health and Disease

Chairperson

Ramón Reig

OVERALL ABSTRACT

Code

SY09


The basal ganglia (BG) are compound by several and interconnected subcortical nuclei that modulate the activity of the cerebral cortex and thalamus. They are involved in a large variability of functions such as control of the voluntary movements, motor learning, decision making, reward, and also cognitive and emotional functions. Dysfunctions of the BG leads to numerous and devastated pathologies such as Parkinson’s disease, Huntington disease, Tourette syndrome, dystonia, addictions, obsessive-compulsive disorder, and others. In order to understand the functions and problems of the BG it is essential to have a profound understanding of the circuit anatomy, physiology and synaptic dynamics, as well as their interactions with different neurotransmitter systems, as for example dopamine or acetylcholine. This level of understanding can only be reached by different and complementary experimental approach: behavior, circuit and single cell physiology, and molecular tools. In this symposium we will present recent scientific advances in BG research. The talks will cover a variety of state-of-the art methods, including behavior paradigms, animal models of basal ganglia diseases, optogenetics, slice and in-vivo electrophysiology, immunostaining, and computational models. The international proposed symposium is compound by EU scientists (UK, Sweden and Spain), than using different approaches pretend to understand in detail how the basal ganglia work in functional and dysfunctional states. The symposium is suitable to a wide audience, from graduate students to BG experts. In the Spanish neuroscience community, as well as in the international one, there is a growing interest in the BG. Recent insets in the field, in functions (motor and not motor related), and connectivity (just to mention one, new direct connections between the external globus pallidum and prefrontal cortex) has increased conspicuously their potential interest. Malfunctions of these circuits are related with a large number of diseases and disorders, and for example, there is a large community of Spanish research groups focus in Parkinson’s diseases (CIMA, Instituto Cajal, Universidad Autónoma de Barcelona, CIBERNET, Instituto de Investigación Sanitaria Biodonostia, among others). The precise knowledge of the neurophysiology and functions of the basal ganglia is essential to understand the different diseases or disorders involving them. The proposed symposium targets a broader spectrum of audience that can benefit both clinical and basic researchers. The speakers are consolidated experts in the field and cover large range of different techniques, from molecular to behavioral approaches.

Speakers

1. 2. 3. 4.

Peter Magill. MRC-University of Oxford Rosario Moratalla. Instituto Cajal, CSIC Gilad Silberberg. Karolinska Institutet Ramón Reig. Instituto de Neurociencias

Contact:

Ramón Reig. [email protected]

Session:

Symposium

Title:

Neuronal substrates of a division of labor in the external globus pallidus

Speaker

Peter Magill

Abstract

P.J. Magill 1 1. University of Oxford, Oxford, United Kingdom

SPEAKER 1

Code

SY09

Classical schemes of the functional organization of basal ganglia circuits are founded on two key principles: (1) Neurons of the external globus pallidus (GPe) are relatively homogeneous in form and function; and (2) information flows from striatum to GPe, but not vice versa. In this symposium presentation, I will highlight how recent studies of GPe cells and circuits in dopamine-intact and dopamine-depleted brains challenge both of these tenets. Electrophysiology in vivo and in vitro, single-cell recording/labelling, molecular profiling, genetic fate www.congreso-senc.com

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Abstracts: Symposia


mapping, computational modelling, optogenetics. It is now clear that the distinct temporal activities of two populations of GPe neuron in vivo are underpinned by their distinct developmental origins, molecular architecture and axonal connectivities. Thus, a first population of “prototypic” GPe neurons express the transcription factors Nkx2-1 and Lhx6, fire at high rates and anti-phase to striatal projection neurons, and mainly target downstream basal ganglia nuclei. In contrast, a second population of “arkypallidal” neurons express the transcription factor FoxP2, fire at low rates and in-phase with striatal projection neurons, and only innervate striatum. Prototypic and arkypallidal neurons also disparately encode spontaneous movements. Computational models predict that the divergent firing rates/patterns of prototypic and arkypallidal neurons in vivo arise from their distinct intrinsic membrane properties as well as their different inputs from striatal and other neurons; some predictions have already been validated by studies in vitro. Two types of GPe neuron are well suited to perform a division of labor when orchestrating activity in the basal ganglia. Recent publications

1.

2. 3.

Dodson PD, Dreyer JK, Jennings KA, Syed ECJ, Wade-Martins R, Cragg SJ, Bolam JP, Magill PJ. Representation of spontaneous movement by dopaminergic neurons is cell-type selective and disrupted in parkinsonism. 2016. Proc. Natl. Acad. Sci. U.S.A., 113(15): E2180-E2188. Dodson PD, Larvin JT, Duffell JM, Garas FN, Doig NM, Kessaris N, Duguid IC, Bogacz R, Butt SJB, Magill PJ. Distinct developmental origins manifest in the specialized encoding of movement by adult neurons of the external globus pallidus. 2015. Neuron, 86(2): 501-13 Henny P, Brown MTC, Northrop A, Faunes M, Ungless MA, Magill PJ, Bolam JP. Structural correlates of heterogeneous in vivo activity of midbrain dopaminergic neurons. 2012. Nat. Neurosci., 15(4): 613-9.

Session:

Symposium

Title:

L-DOPA oppositely regulates synaptic strength and spine morphology in D1 and D2 striatal projection neurons in dyskinesia

Speaker

Rosario Moratalla

SPEAKER 2

Code

SY09


1. 2. 3.

Suarez LM, Solis O, Aguado C, Lujan R, Moratalla R. L-DOPA oppositely regulates synaptic strength and spine morphology in D1 and D2 striatal projection neurons in dyskinesia. Cereb Cortex. 2016. DOI: 10.1093/cercor/bhw263 Suárez LM, Solís O, Caramés JM, Taravini IR, Solís JM, Murer MG, Moratalla R. LDOPA treatment selectively restores spine density in dopamine receptor D2-expressing projection neurons in dyskinetic mice. Biol Psychiatry. 2014. 75:711-22. Darmopil S, Martín AB, Ruiz de Diego I, Ares S, Moratalla R. Genetic inactivation of dopamine D1 but not D2 receptors inhibits L-DOPA-induced dyskinesia and histone activation. Biol Psychiatry. 2009. 66:603-613.

Session:

Symposium

Title:

Striatal microcircuits underlying sensorimotor functions

Speaker

Gilad Silberberg

SPEAKER 3

Code

SY09


1. 2. 3.


Munoz-Manchado, A.B., Foldi, C., Szydlowski, S., Sjulson, L., Farries, M., Wilson, C., Silberberg, G. & Hjerling-Leffler, J. Novel Striatal GABAergic Interneuron Populations Labeled in the 5HT3aEGFP Mouse. Cereb Cortex (2016) Jan;26(1):96-105. Pollak Dorocic, I., Furth, D., Xuan, Y., Johansson, Y., Pozzi, L., Silberberg, G., Carlen, M. & Meletis, K. A whole-brain atlas of inputs to serotonergic neurons of the dorsal and median raphe nuclei. Neuron. 83, 663-678 (2014). Szydlowski, S.N., Pollak Dorocic, I., Planert, H., Carlen, M., Meletis, K. & Silberberg, G. Target selectivity of feedforward inhibition by striatal fast-spiking interneurons. J Neurosci. - 45 -

Abstracts: Symposia


33, 1678-1683 (2013). Session:

Symposium

Title:

Target selectivity in the striatal microcircuits

Speaker

Ramón Reig

SPEAKER 4

Code

SY09


1. 2. 3.


Reig R & Silberberg G. Corticostriatal pathways underlying bilateral sensory integration in the mouse striatum – a whole-cell in vivo study. Cerebral Cortex. doi: 10.1093/cercor/bhw268 (2016). Reig R, Zerlaut Y, Vergara R, Destexhe A, Sanchez-Vives MV. Gain modulation of synaptic inputs by network state in auditory cortex in vivo. Journal of Neuroscience. 35(6): 2689-2702 (2015). Reig R & Silberberg G. Multisensory integration in the mouse striatum. Neuron. 83(5) 12001212 (2014).

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Symposium SY10. Neuroendocrine regulation of homeostasis


- 47 -


Session:

Symposium

Title:

Neuroendocrine regulation of homeostasis

Chairperson

Javier Morante, Francisco A. Martin

OVERALL ABSTRACT

Abstracts: Symposia

Code

SY10


The selected topic, homeostatic and neuroendocrine systems, has experienced a significant advance lately due to the development of novel techniques and the use of a wide variety of model systems. In this symposium we will address the effect of hormonal response in the homeostasis of the organism during development and adulthood, particularly on two aspects. On one hand, the effect that hormones themselves have on the CNS and neuronal function. For instance, Drosophila dilp8 is a crucial developmental switch that serves as tissue quality control that exerts its ultimate effect on the brain. Another example comes from studies on the thyroid hormone and its effect on the human brain. On the other hand, striking functional similarities between the neuroendocrine system of insects and mammals exist, despite huge evolutionary differences. For instance, human GnRH-GH-steroid hormones and insect ptth-ecdysone axis play similar roles in regulating juvenile-adult transition (puberty and metamorphosis, respectively). Moreover, in recent years intense study of these axis have allowed to identify new players and novel functions for known molecules, both in Drosophila and mammals. Our intention in this symposium is to have a complete picture of recent findings in neuroendocrine regulation of homeostasis in both model systems, with the final aim of establishing parallelisms, similarities and differences. All Invited speakers have made significant and recent advances in the field. The age of puberty—the transition from childhood to sexual maturity and reproductive ability—has fallen markedly over the last century in humans. These changes likely reflect increases in childhood nutrition and body size, but exposures to endocrine-disrupting chemicals or other specific environmental factors have also been proposed. Earlier puberty timing is associated with greater propensity for risktaking behaviors and lower educational attainment. Despite this social relevance, we know very little about how juvenile organisms (and their brain) know when it is time to enter puberty. In particular, how body fat is integrated and regulated in order to dictate when an animal becomes sexually mature. In mammals, recent studies have shown that Leptin and Kisspeptin neuropeptides convey energy and fat-content information to and within the brain. But, how brain neurons do monitor and process body fat remains a complete mystery, yet most animals (and children) initiate pubertal development (juvenile-to-adult transition or metamorphosis in insects) only once enough body fat has been stored to ensure survival through metamorphosis and reproductive success. Also, the effect of hormones in the brain is of vital importance, and its dysregulation during development and adulthood causes several diseases. In this symposium we will discuss the latest advances in the neuroendocrine regulation of juvenile- toadult transition or metamorphosis in insects, as well as the effect of hormones in the CNS and its implications on human diseases. Showing the parallelisms between two model systems that seem to be quite different will open interesting scientific discussions.

Speakers

1. 2. 3. 4.

María Domínguez Castellano. Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas y Universidad Miguel Hernandez Manuel Tena-Sempere. Physiology Section, Faculty of Medicine, University of Cordoba, and Maimonides Institute of Biomedical Research of Cordoba (IMIBIC) Nuria M Romero. Institut de Biologie Valrose (CNRS-INSERM-U. Sophie-Antipolis), Nice, France. Ana Guadaño Ferraz. Instituto de Investigaciones Biomédicas Alberto Sols (CSIC-UAM). Madrid, Spain.

Contact:

Javier Morante, Francisco A. Martin; [email protected], [email protected]

Session:

Symposium

Title:

It’s not the right time: How the brain resets the ‘growth’ clock and delays maturation.

Speaker

María Domínguez Castellano

SPEAKER 1

Code

SY10

Abstract


- 48 -

Abstracts: Symposia


Recent publications

1. 2.

A brain circuit that synchronizes growth and maturation revealed through Dilp8 binding to Lgr3. Vallejo DM#, Juarez-Carreño S#, Bolivar J, Morante J*, Domínguez M*. Science (2015) 350:aac6767. Imaginal discs secrete insulin-like peptide 8 to mediate plasticity of growth and maturation. Garelli A, Gontijo AM, Miguela V, Caparros E, Dominguez M. Science (2012) 336:579- 82.

Session:

Symposium

Title:

Novel neuroendocrine mechanisms for the control of pubertal transition in mammals

Speaker

Manuel Tena-Sempere

SPEAKER 2

Code

SY10


1.

2. 3.

Defining a novel leptin-melanocortin-kisspeptin pathway involved in the metabolic control of puberty. Manfredi-Lozano M, Roa J, Ruiz-Pino F, Piet R, Garcia-Galiano D, Pineda R, Zamora A, Leon S, Sanchez-Garrido MA, Romero-Ruiz A, Dieguez C, Vazquez MJ, Herbison AE, Pinilla L, Tena- Sempere M. Mol Metab (2016) 5: 844-57. A microRNA switch regulates the rise in hypothalamic GnRH production before puberty. Messina A, Langlet F, Chachlaki K, Roa J, Rasika S, Jouy N, Gallet S, Gaytan F, Parkash J, Tena- Sempere M, Giacobini P, Prevot V. Nat Neurosci. 2016 Jun;19(6):835-44. Direct actions of Kisspeptins on GNRH neurons permit attainment of fertility but are insufficient to fully preserve gonadotropic axis activity. León S, Barroso A, Vázquez MJ, García- Galiano D, Manfredi-Lozano M, Ruiz-Pino F, Heras V, Romero-Ruiz A, Roa J, Schutz G, Kirilov M, Gaytan F, Pinilla L, Tena-Sempere M. Sci Rep. (2016) 6:19206.

Session:

Symposium

Title:

How does the brain control puberty?

Speaker

Nuria M Romero

SPEAKER 3

Code

SY10


1. 2. 3.

Drosophila Lgr3 Couples Organ Growth with Maturation and Ensures Developmental Stability. Colombani J, Andersen DS, Boulan L, Boone E, Romero N, Virolle V, Texada M, and Léopold P. Current Biology (2015) 25:2723-2729 Neuroendocrine control of Drosophila larval light preference. Yamanaka N*, Romero NM*, Martin FA*, Rewitz KF, Sun M, O'Connor MB, Léopold P. Science (2013) 341:1113-6. Drosophila genome-wide RNAi screen identifies multiple regulators of HIF-dependent transcription in hypoxia. Dekanty A, Romero NM, Bertolin AP, Thomas MG, Leishman CC, Perez- Perri JI, Boccaccio GL, Wappner P. PLoS Genet (2010) e1000994.

Session:

Symposium

Title:

Physiological and pathophysiological implications of thyroid hormones transmembrane transport in the CNS

Speaker

Ana Guadaño Ferraz

Abstract

A. Guadaño-Ferraz1 1. Consejo Superior de Investigaciones Científicas, Madrid, Spain

SPEAKER 4

Code

SY10

Normal Thyroid hormone (TH) action is essential for a correct development and functioning of the CNS. In humans, the deficiency of THs and impairments in TH signaling at critical periods of development induce severe structural and functional damage to the CNS, the majority of them irreversible unless an adequate treatment is undertaken. THs are secreted by the thyroid gland, and due to their small size and amphipathic nature it was postulated that they crossed cellular membranes by passive transport. However, it has been recently www.congreso-senc.com

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Abstracts: Symposia

demonstrated that in order to be available for brain and neural cells THs cross the membranes by transmembrane proteins. In humans, mutations in the specific TH membrane transporter Monocarboxylate 8 (MCT8) are associated to the Allan-Herndon-Dudley Syndrome, which presents severe neurological symptoms indicating the importance of an adequate control of the TH content for neural cells. In addition, the most abundant secreted TH, the T4 or thyroxine, must also be metabolized in the brain to the genomically active hormone T3 or triiodothyronine. Knowing the mechanisms of TH availability for neural cells, specially their transport across cellular membranes and their metabolism in neural cells, is crucial to understand TH actions in health and disease. However, these processes in the human brain are almost unknown. We conducted histological studies in autopsy brain tissue by means of immunohistochemistry and immunofluorescence, in situ hybridization and other histological techniques, to determine the cells involved in the transport and metabolism of THs in the human brain, and to describe for the first time aspects of the brain histopathology of MCT8 deficiency. Overall our recent findings have implications for understanding and treating MCT8 deficiency and other TH signaling alterations in the human brain. This work was supported by the Spanish Ministry of Economy and competitiveness (Grant numbers SAF2011-25608 and SAF2014-54919-R. Recent publications

1. 2. 3.


Effect of Triiodothyroacetic Acid Treatment in Mct8 Deficiency: A Word of Caution. BárezLópez S, Obregon MJ, Martínez-de-Mena R, Bernal J, Guadaño-Ferraz A*, Morte B*. Thyroid. 2016 May;26(5):618-26. *Co-senior authors Thyroid hormone transporters-functions and clinical implications. Bernal J, Guadaño-Ferraz A, Morte B. Nat Rev Endocrinol. 2015 Dec;11(12):690. Mutations of the thyroid hormone transporter MCT8 cause prenatal brain damage and persistent hypomyelination. López-Espíndola D, Morales-Bastos C, Grijota-Martínez C, Liao XH, Lev D, Sugo E, Verge CF, Refetoff S, Bernal J, Guadaño-Ferraz A. J Clin Endocrinol Metab. 2014 Dec;99(12):E2799-804.

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Symposium SY11. Neuron-glia interactions: from molecules to behavior


- 51 -

Abstracts: Symposia


Session:

Symposium

Title:

Neuron-glia interactions: from molecules to behavior

Chairperson

Gertrudis Perea

Co-chairperson

Marta Navarrete

Abstract

The glial cell physiology is one of the hot topics in neuroscience in recent years. Astrocytes, particularly, have received great attention due to their strategic position at the synapse. In addition to the well-known metabolic support for neurons and brain homeostasis, providing nutrients and antioxidants, and by recycling neurotransmitters, increasing evidence suggests that glial cells play important roles in neurotransmission modulating the strength of synaptic interactions, being an active element in the information coding by neural circuits. Neuronal networks cooperate in the brain to generate behavior, permitting sensation and cognition. Thus, the synaptic connections that drive brain activities are finely tuned by neuronal mechanisms, but also by glial processes, and any imbalance in the neuron-glia networks might lead to aberrant synaptic transmission and cognitive diseases. Therefore, present symposium proposal aims to show and discuss novel findings regarding the cellular bases and signaling mechanisms that involve glial cells in underlying fundamental aspects of the brain function and dysfunction, such as Alzheimer´s disease. It will show from the molecular and cellular to circuit and system levels the complexity of this signaling to expand our view about the impact of astrocyte signaling on neuronal activity, brain function and animal behavior. Dr. Rodriguez Moreno and Dr. Fuenzalida will discuss the molecular mechanisms and specific targets related with synaptic transmission and long term plasticity driven by astrocytes. Dr. Oliveira and Dr. Navarrete will examine the role of gliotransmitters released by astrocytes on hippocampal and cortical circuits and their impact on animal behavior. Astrocyte-neuron signaling is an emerging field that is challenging our concept of the brain function. In the last years, evidence obtained by many laboratories has established the existence of neuron- astrocyte communication in different brain areas, showing an important function of these glial cells for the circuits information coding. The results shown in this symposium will comprise the molecular and cellular description of neuron-astrocyte signaling (i.e., membrane receptors, intracellular pathways involved, etc), and the impact of this neuron-astrocyte signaling for the circuit function and animal behavior, being of interest for broad background SENC’s memberships. We consider that this symposium will provide an opportunity for SENC memberships to gain deeper insights into recent conceptual findings on this topic, as well as on novel techniques and methodologies to study the glia-neuron interactions.

Speakers

1. 2. 3. 4.

OVERALL ABSTRACT

Code

SY11

Antonio Rodríguez Moreno. Glial role in spike timing-dependent plasticity Marco Fuenzalida. Centro de Neurobiología y Plasticidad Cerebral, Instituto de Fisiología, Facultad de Ciencias, Universidad de Valparaíso. Valparaíso, Chile. João Filipe Oliveira. ICVS/3B’s Associate Laboratory, School of Medicine, Braga, Portugal. Marta Navarrete. Centro de Biología Molecular "Severo Ochoa," Consejo Superior de Investigaciones Científicas (CSIC-UAM). Madrid, Spain.

Contact:

Gertrudis Perea, Marta Navarrete. [email protected]; [email protected]

Session:

Symposium

Title:

Glial role in spike timing-dependent plasticity

Speaker

Antonio Rodríguez Moreno

Abstract

Antonio Rodríguez-Moreno. Universidad Pablo de Olavide. Sevilla, Andalucía, Spain.

SPEAKER 1

Code

SY11

Spike timing-dependent plasticity (STDP) is a Hebbian learning rule important for refinement during development and for learning and memory in the adult. The role of astrocytes in STDP and the mechanisms involved are not well known. To investigate the role of astrocytes in the induction of spike timing-dependent long-term depression (tLTD) and long-term potentiation (t-LTP) in the hippocampus. We performed experiments in the CA1 region of hippocampal slices prepared from mice (P13-P18) using www.congreso-senc.com

- 52 -

Abstracts: Symposia


the whole-cell configuration of the patch clamp technique. Dual recordings from astrocytes and neurons were obtained when necessary. To induce t-LTP, a pre-post pairing protocol (with the presynaptic activity occurring 5 ms before a postsynaptic action potential) was applied after a stable EPSP baseline period of 10 min. To induce t-LTD a post-pre protocol (18 ms interval) was applied. EPSP slope was monitored for at least 30 min after the pairing protocol. We found that a post-pre pairing protocol induced robust t-LTD (70 ± 5%, n = 8) while a pre-post protocol induced robust t-LTP (159 ± 7 %, n = 7)). In the presence of fluoroacetate (10 mM) or BAPTA (20 mM, loaded into the astrocytes), t-LTD induction was prevented (111 ± 18 %, n = 6, 121 ± 8%, n = 5, respectively). t-LTP was resistant to fluoroacetate treatment (136 ± 6 %, n = 6) and not affected by BAPTA loading into astrocytes (147 ± 4 %, n = 5). t-LTD was completely recovered in BAPTA-loading experiments, when repeated in the presence of D-serine (60 ± 8 %, n = 7). t-LTP induction does not require the release of gliotransmitters from astrocytes at SC-CA1 synapses whereas, at these synapses, t-LTD requires the release of the gliotransmitter D-serine, a co-agonist of NMDA receptors. Recent publications

1. 2. 3.

Andrade-Talavera Y, Duque-Feria P, Paulsen O, Rodríguez-Moreno A. Presynaptic Spike Timing-Dependent Long-Term Depression in the Mouse Hippocampus. Cereb Cortex. 2016 Aug;26(8):3637-54. doi: 10.1093/cercor/bhw172. Rodríguez-Moreno A, González-Rueda A, Banerjee A, Upton AL, Craig MT, Paulsen O. Presynaptic self-depression at developing neocortical synapses. Neuron. 2013 Jan 9;77(1):3542. doi: 10.1016/j.neuron.2012.10.035. Rodríguez-Moreno A, Paulsen O. Spike timing-dependent long-term depression requires presynaptic NMDA receptors. Nat Neurosci. 2008 Jul;11(7):744-5. doi: 10.1038/nn.2125.

Session:

Symposium

Title:

Serotonin neuromodulation of inhibitory synaptic plasticity.

Speaker

Marco Fuenzalida

Abstract

M.A. Pérez1, K. Morales1, J. Ahumada1, A. Martorell1 C. Bonansco1 and M. Fuenzalida1. Centro de Neurobiología y Plasticidad Cerebral CNPC, Instituto de Fisiología, Facultad de Ciencias, Universidad de Valparaíso, Chile.

SPEAKER 2

Code

SY11

Objectives: In several brain areas, the excitatory and inhibitory synaptic plasticity can occur simultaneously. The same patterns of activation that trigger LTP in excitatory synapses can also induce short- or long-lasting plasticity in inhibitory synapses. This functional balance between excitatory and inhibitory synapses is established during development and maintained throughout life and is essential to brain function. In the mammalian brain, several neurotransmitters are powerful modulators of synaptic plasticity and brain function. Related to excitatory transmission, less attention has been focused in the role of neuronal and non-neuronal signaling on the GABA neurotransmission and its contribution to brain mechanisms of learning and memory. The main goal of this work was to evaluate the role of diverse neuromodulators in GABA synaptic plasticity. Methods: Here, we use electrophysiological recordings in combination with pharmacological and calcium image tools in rat hippocampal slices to study the role of neuromodulators and crosstalk astrocyte-neurons on the GABA transmission. Results: we showed that 1) the co-activation of endocannabinoids and cholinergic receptors can induce GABAergic long-term plasticity in hippocampal neurons; 2) activation of serotonin receptors induces long-lasting modifications in GABA transmission in prefrontal cortex; 3) we determine that crosstalk neuron-astrocyte signaling can modulate the excitatory transmission and GABA synaptic efficacy in hippocampus. Conclusions: Our result suggests that changes in GABA synaptic efficacy, summed to powerful crosstalk astrocyte-neurons have profound consequences for neural excitability. We expect that results from all these experiments will allow us to reveal the functional impact of neuromodulation in the excitatoryinhibitory balance under normal condition, as well as in several neurological and mental diseases. Grants: Conicyt- Fondecyt, Chile Nº 1171006; Conicyt-Anillo PAI: ACT 1414; Millennium Nucleus NU-MIND NC-130011. Recent publications


1.

Vargas JY, Fuenzalida M, Inestrosa NC. In vivo activation of Wnt signaling pathway enhances cognitive function of adult mice and reverses cognitive deficits in an Alzheimer's disease model. J Neurosci. 2014 Feb 5;34(6):2191-202. doi: 10.1523/JNEUROSCI.0862-13.2014. - 53 -

Abstracts: Symposia


2.

3.

Ahumada J, Fernández de Sevilla D, Couve A, Buño W, Fuenzalida M. Long-term depression of inhibitory synaptic transmission induced by spike-timing dependent plasticity requires coactivation of endocannabinoid and muscarinic receptors. Hippocampus. 2013 Dec;23(12):1439-52. doi: 10.1002/hipo.22196. Ardiles AO, Flores-Muñoz C, Toro-Ayala G, Cárdenas AM, Palacios AG, Muñoz P, Fuenzalida M, Sáez JC, Martínez AD. Pannexin 1 regulates bidirectional hippocampal synaptic plasticity in adult mice. Front Cell Neurosci. 2014 Oct 15;8:326. doi: 10.3389/fncel.2014.00326.

Session:

Symposium

Title:

The involvement of astrocytes in cognitive processing

Speaker

João Filipe Oliveira

Abstract

V. M. Sardinha1,2, S. Guerra-Gomes1,2, I. Caetano1,2, G. Tavares1,2, M. Martins1,2, J. S. Reis1,2, J. S. Correia1,2, A. Teixeira-Castro1,2, L. Pinto1,2, N. Sousa1,2, J.F. Oliveira1,2,3

SPEAKER 3

Code

SY11

1 Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Campus Gualtar, 4710-057 Braga, Portugal; 2 ICVS/3B’s - PT Government Associate Laboratory, Braga/Guimarães, Portugal 3 DIGARC, Polytechnic Institute of Cávado and Ave, 4750-810 Barcelos, Portugal Astrocytes interact with neurons at the cellular level through modulation of synaptic formation, maturation and function, but the impact of such interaction into behavior remains unclear. The goal of this work was to assess the role of astrocyte-derived signaling to the neuronal circuits and respective behavior outputs. Here, we studied the dominant negative SNARE (dnSNARE) mouse model to dissect the role of astrocyte-derived signaling in cortico-hippocampal circuits, with implications for cognitive processing. We found that the blockade of gliotransmitter release in astrocytes triggers a critical desynchronization of neural theta oscillations between dorsal hippocampus and prefrontal cortex. Moreover, we found a strong cognitive impairment in tasks depending on this network. Importantly, the supplementation with D-serine completely restores hippocampal-prefrontal theta synchronization and rescues the spatial memory and long-term memory of dnSNARE mice. These results provide a novel mechanism of long distance network modulation by astrocytes, with direct implications to cognitive function. Recent publications

1. 2.

3.

Oliveira JF, Sardinha VM, Guerra-Gomes S, Araque A, Sousa N (2015). Do stars govern our actions? Astrocyte involvement in rodents’ behavior. Trends in Neurosciences 38:535–549. Lima A, Sardinha VM, Oliveira AF, Reis M, Mota C, Silva MA, Marques F, Cerqueira JJ, Pinto L, Sousa N, Oliveira JF (2014) Astrocyte pathology in the prefrontal cortex impairs the cognitive function of rats. Molecular Psychiatry 19, 834–841. Oliveira JF, Gomes CA, Vaz SH, Sousa N, Pinto L (2016) Editorial: Glial Plasticity in Depression. Frontiers in Cellular Neuroscience 10

Session:

Symposium

Title:

Astrocytes as key drivers in NMDA receptor-depedent long term depression

Speaker

Marta Navarrete

Abstract

Marta Navarrete1, Rocío Palenzuela1,2, Jonathan E. Draffin1, Ainoa Konomi1, Ángel R. Nebreda3 and José A. Esteban1.

SPEAKER 4

Code

SY11

1Department of Neurobiology, Centro de Biología Molecular “Severo Ochoa” (CSIC-UAM), Madrid 28049, Spain 2School of Biosciences, Universidad Francisco de Vitoria, Pozuelo de Alarcón, Madrid, Spain 3Institute for Research in Biomedicine (IRB Barcelona), Barcelona Institute of Science and Technology, 08028 Barcelona, Spain.


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Abstracts: Symposia

Astrocytes are increasingly being recognized as active players for neuronal synaptic communication, with multiple functions for central nervous system physiology. Nevertheless, astrocytes are typically considered as modulators of core mechanisms driven by the neuronal components, or are thought to provide metabolic fine-tuning for neuronal function (for instance by regulating neurovascularneuroenergetic coupling). To investigate the involvement of astrocytes in the hippocampal NMDAR-dependent Long Term Depression (LTD) of CA3-CA1 synaptic transmission. Electrophysiological, optogenetic, chemogenetic and imaging techniques in murine hippocampal slices. Results: We have found that LTD induction (low frequency presynaptic activity) triggers calcium signaling in the astrocyte and enhances astrocytic glutamate release. This source of glutamate is then responsible for the activation of postsynaptic NMDA receptors and synaptic depression. In fact, presynaptic activity can be completely bypassed by optogenetic activation of astrocytic glutamate release, which is then sufficient to induce LTD. Importantly, using cell type-specific genetic deletions, astrocyte, and is required for LTD. This result also serves to clarify the role of p38 MAPK in LTD, which had been rather controversial because of the failure to identify the neuronal locus (presynaptic or within the astrocyte. In short, we will present a fundamental change of paradigm, in which the axis composed of presynaptic neuron-astrocyte-postsynaptic neuron defines an obligatory relay for information processing leading to synaptic plasticity. Supported by: “I Convocatoria De Ayudas Fundación BBVA a Investigadores, Innovadores y Creadores Culturales”; L’Oreal-UNESCO for woman in Science and MINECO (FEDER) SAF2014-58598-JIN. Recent publications

1. 2. 3.


Gómez-Gonzalo M*, Navarrete M*, Perea G*, Covelo A*, Martín-Fernández M, Shigemoto R, Luján R, Araque A. 2014 Endocannabinoids induce lateral long-term potentiation of transmitter release by stimulation of gliotransmission. Cereb Cortex, pii: bhu231. Perez-Alvarez A*, Navarrete M*, Covelo A, Martín ED, Araque A. 2014 Structural and functional plasticity of astrocyte process and dendritic spine interactions. J Neurosci, 34:12738 –12744. Navarrete M, Perea G, Fernandez de Sevilla D, Gómez-Gonzalo M, Núñez A, Martín ED and Araque A. 2012 Astrocytes mediate in vivo cholinergic-induced synaptic plasticity. PLoS Biology, 10:e1001259.

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Abstracts: Symposia

- 56 -

Symposium SY12. Shared principles of animal behavior across species


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Abstracts: Symposia


Session:

Symposium

Title:

Shared principles of animal behavior across species

Chairperson

Alex Gomez-Marin

OVERALL ABSTRACT

Code

SY12


Current neuroscience is thriving with the advent of “big tools” (optogenetics, Ca2+ imaging in freely behaving animals, multi-electrode arrays, etc) and “big data” (high-resolution automated measurements, unsupervised methods inspired by machine learning, etc). However, to ultimately fulfill the promise of “understanding the brain”, some grand challenges still lie ahead. We wish to address three of them, somewhat orthogonal to “bigger tools” or “bigger data”. All essential to neuroscience, timely given the fact that they are for the first time addressable quantitatively today, and obviously interrelated, they are: behavior, theory and cross-species comparisons. (i)Behavior is not simply a tool for helping neuroscientists interpret brain data, but also the foundational problem of neuroscience. In a word, we won’t understand the brain by studying the brain alone; neuroscience needs behavior. (ii)But, proper behavioral quantification is not just about “putting a number” to every phenomenon, but should also reflect high-level assumptions about what is relevant and what is not. In a word, measurement is not enough to understand behavior; we need theory in the form of testable hypotheses to be shaped by high-level principles. (iii)Finally, as studying a particular organism has value in its own right, the very notion of “model organism” offers the possibility to test for shared principles of organization across species. The effort to ground what aspects of the behavior of a worm and a mouse are the same, just similar or perhaps different can shed invaluable light into brain mechanisms, its organization and evolution. Combining precise kinematic measurments with neuromuscular electromyographic signals, Dr. Lacquaniti will discuss recent efforts in establishing locomotor primitives in 47 different terrestial animals, reporting a planar covariance law found in all species. Dr. Stephens will use exquisite worm tracking data and basic notions of nonlinear dynamical systems to demonstrate that locomotion lies on a low-dimensional attractor, reconciling global stereotypy with local variability in their movement, and providing a continuous view on animal behavior, that does not require to impose discrete behaviors. Using detailed and realistic models, Dr. Gjorjieva will quantitatively link the body plant of the fly larva with the neural circuits governing muscle contractions that direct straight and curved spontaneous crawling. Dr. Bartumeus will present new theoretical insights based on recent high-quality data of search behavior and stochastic theory to show that the exploration-exploitation dilemma needs to add a third (perhaps-missed) component: relocation. Dr. Akam will discuss recent progress in the design and application of two novel decision tasks that allow to dissect model-based versus model-free behavior during maze-planning and reward-seeking in rodents, in conjunction to optogenetic manipulations. Applying the core ideas of genome-wide association studies now to behavior, Dr. Brown will use the current power of large-scale imaging in worms to reveal novel traits and basic properties of the genotypephenotype map. For more detailed information see preliminary abstracts and selected publications below. The nature of the topic covered and the quality of the international speakers that accepted our invitation makes this proposal specially suited to the goals of the SENC, as it targets the nervous system at multiple levels of organization (genetic, circuit, behavioral, evolutionary; see more info below), gathers scientists of different disciplines (in terms of the very different organisms they study and the methods used), encourages education for our students (as it comes back to the basis of neuroscience by digging into “what is behavior”, appealing to the notion of “model” organisms, and introducing top-notch theoretical and computational methods), and undoubtedly promotes further bonds with national and international neuroscience communities in Europe (as our selected speakers come from renowned centers in Spain, Germany, UK, Netherlands and Italy).

Speakers

1. 2. 3. 4.

Francesco Lacquaniti. University of Rome Tor Vergata and Scientific Institute Santa Lucia, Rome (Italy) Greg Stephens. VU University Amsterdam (The Netherlands) Julijana Gjorgjieva. Max Planck Institute for Brain Research (Germany) Frederic Bartumeus. Centre d'Estudis Avançats de Blanes, CSIC (Spain)

Contact:

Alex Gomez-Marin. [email protected], [email protected]

Session:

Symposium


SPEAKER 1

Code

SY12 - 58 -


Abstracts: Symposia

Title:

Comparative analysis of locomotion across terrestrial animals

Speaker

Francesco Lacquaniti

Abstract

There is increasing evidence that several different principles of locomotor control are conserved across animal species, consistent with the hypothesis that, despite substantial phylogenetic distances and morphological differences, locomotion is built starting from common primitives, related to either conserved features of an ancestral neural network or convergent evolution. I will present evidence we collected concerning both kinematic invariants of locomotion and the underlying neuromuscular control modules. With regards to the former, we recorded in field walking of 47 different terrestrial animals, ranging from birds to ungulates and digitigrades. We analyzed the changes of the elevation angles at both forelimbs (for quadrupeds) and hindlimbs and computed the principal components. We found that a planar covariance law is obeyed in all tested animal species, but the orientation of the plane differs across animals as a function of mechanical constraints and phase shifts in the control of each segment. With regards to the neuromuscular control, we performed factorization of the electromyographic signals recorded in different species during walking and found very similar factors across tested animals.

Recent publications

1. 2. 3.

Hand interception of occluded motion in humans: a test of model-based vs. on-line control (2015) B La Scaleia, M Zago, F Lacquaniti. Journal of neurophysiology 114 (3), 1577-1592 Development of human locomotion (2012) F Lacquaniti, YP Ivanenko, M Zago. Current opinion in neurobiology 22 (5), 822-828 Locomotor primitives in newborn babies and their development (2011) N Dominici, Y P Ivanenko, G Cappellini, A d’Avella, V Mondì, M Cicchese, A Fabiano, T Silei, A Di Paolo, C Giannini, R E Poppele, F Lacquaniti. Science 334 (6058), 997-999

Session:

Symposium

Title:

Capturing the continuous complexity of natural movement in C. elegans

Speaker

Greg Stephens

Abstract

T. Ahamed1, G.J. Stephens1,2 1. OIST Graduate University, Okinawa, Japan 2. Vrije Universiteit Amsterdam, Amsterdam, Netherlands

SPEAKER 2

Code

SY12

While animal behavior is often quantified though discrete, stereotyped motifs and transitions between them, this is only an approximation to fundamentally continuous dynamics and ignores important variability within each motif. Here, we use high-resolution video imaging to reconstruct the phase space of the nematode C. elegans. We show that the dynamics lie on a 6D manifold, which is globally composed of three sets of cyclic trajectories that form the animal’s basic behavioral motifs: forward, backward and turning locomotion. In contrast to global stereotypy, large local variability is evident in positive Lyapunov exponents for each set of cycles. Across the full phase space the Lyapunov spectrum is remarkably symmetric with positive, chaotic exponents driving variability balanced by negative, dissipative exponents driving stereotypy. The symmetry of the spectrum holds for different environments and for human walking suggesting a general condition of motor control. Recent publications

1. 2. 3.

Session:

Resolving coiled shapes reveals new reorientation behaviors in C. elegans (2016) OD Broekmans, JB Rodgers, WS Ryu, GJ Stephens. eLife 2016;5:e17227 Searching for simplicity in the analysis of neurons and behavior (2011) GJ Stephens, LC Osborne, W Bialek. Proceedings of the National Academy of Sciences 108 (Supplement 3), 15565-15571 Dimensionality and dynamics in the behavior of C. elegans (2008) GJ Stephens, B JohnsonKerner, W Bialek, WS Ryu. PLoS Comput Biol 4 (4), e1000028

Symposium


SPEAKER 3

Code

SY12

- 59 -

Abstracts: Symposia


Title:

Neural circuits for spontaneous navigation in Drosophila larvae

Speaker

Julijana Gjorgjieva

Abstract

J. Gjorgjieva 1,2, M. E. Wosniack 1,2, J. Berni 3 1. Max Planck Institute for Brain Research, Frankfurt, Germany 2. Technical University of Munich, Freising, Germany 3. University of Cambridge, Cambridge, UK Drosophila larvae crawl by peristaltic waves of muscle contractions, which propagate along the animal body and involve the simultaneous contraction of the left and right side of each segment. Coordinated propagation of contraction does not require sensory input, suggesting that movement is generated by a central pattern generator (CPG). We characterized crawling behavior of newly hatched Drosophila larvae by quantifying timing and duration of segmental boundary contractions. We developed several CPG network models that recapitulate these patterns based on segmentally repeated units of excitatory and inhibitory (EI) neuronal populations coupled with immediate neighboring segments. Taking into account a recently published experimental study on the neurons involved in crawling, we examined minimal connectivity requirements between the identified neurons consistent with crawling. Symmetric coupling only between neighboring segments succeeded in generating both forward and backward propagation of activity. We examined the robustness of the CPG network to changes in amplitude and variability of connectivity strength. Introducing sensory feedback via “stretch-sensitive” neurons improved wave propagation properties such as speed of propagation and segmental contraction duration as observed experimentally. Sensory feedback also restored propagating activity patterns when an inappropriately tuned CPG network failed to generate waves. Replicating the segmentally repeated network for the two sides of the bilateral nervous system allowed us to examine the connectivity under which the two independent networks synchronized their activity, as is the case during straight crawling, or generated asymmetric activity, as is the case during turning. We discuss our modeling results in the context of generating Drosophila larva spontaneous behavior, which consists of long bouts of straight crawling interrupted by turning.

Recent publications

1.

2. 3.

Computational implications of biophysical diversity and multiple timescales in neurons and synapses for circuit performance (2016) J Gjorgjieva, G Drion, E Marder. Current Opinion in Neurobiology 37, 4452 Homeostatic activity-dependent tuning of recurrent networks for robust propagation of activity (2016) J Gjorgjieva, JF Evers, SJ Eglen. The Journal of Neuroscience 36 (13), 3722-3734 Neural Circuits for Peristaltic Wave Propagation in Crawling Drosophila Larvae: Analysis and Modeling (2013) J Gjorgjieva, J Berni, JF Evers, S Eglen. Frontiers in Computational Neuroscience 7, 24

Session:

Symposium

Title:

Searching behavior in cognitive systems: linking theory to empirical data

Speaker

Frederic Bartumeus

Abstract

Exploration is a central component of human and animal behaviour. In biological motor systems, conflicts between chance and necessity are encoded at the molecular and neuronal levels, but the actual exploration phenotypes are the resulting trajectories. In the last decade, search theory has progressed enough to frame a powerful background for behavioural hypothesis testing, yet the interface between theoretical insights and experimental data have not been exhaustively explored. Based on full trajectory analyses, which regard about the dynamics of occupancy of a novel environment, we will tightly bridge novel search insights with behavioural quantitative methods in order to understand the non-stationary and stochastic nature of search behaviour.

Recent publications

1. 2. 3.


SPEAKER 4

Code

SY12

Foraging success under uncertainty: search tradeoffs and optimal space use (2016) F Bartumeus, D Campos, WS Ryu, R Lloret-Cabot, V Méndez, J Catalan. Ecology Letters 19 (11), 1299-1313 Signatures of chaos in animal search patterns (2016). AM Reynolds, F Bartumeus, A Kölzsch, J van de Koppel. Scientific reports 6: 23492. Mechanistic analysis of the search behaviour of Caenorhabditis elegans (2014) LCM Salvador, F Bartumeus, SA Levin, WS Ryu. Journal of The Royal Society Interface 11 (92), 20131092

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Symposium SY13. Psychosis as a disorder of neurodevelopment: insights from basic research to the clinic


- 61 -


Abstracts: Symposia

Session:

Symposium

Title:

Psychosis as a disorder of neurodevelopment: insights from basic research to the clinic

Chairperson

Gisela Sugranyes

OVERALL ABSTRACT

Code

SY13


The current symposium sets out to provide insights into the pathophysiology of what is considered to be the most severe psychiatric disorder – psychosis -, and its impact on clinical and therapeutic aspects relevant to patient care. Prof Artigas will focus on the actions of non-competitive NMDA receptor antagonists and serotonergic hallucinogens on neuronal activity in prefrontal cortex and other related structures, such as thalamic nuclei, providing relevant information for the understanding of the neurobiological basis of psychotic symptoms. Dr Horga will focus on the neuroimaging bases of psychosis. While it is established that abnormally elevated dopamine transmission in the striatum plays a central role in psychosis, the cognitive, computational, and network-level mechanisms mediating the expression of symptoms of psychosis has remained elusive. Owing to recent advances in computational neuroscience and functional magnetic resonance imaging methods, Dr Horga’s recent work is beginning to delineate dopamine- dependent computational mechanisms and network dysfunctions that have shed light on the perceptual biases characteristic of psychosis. Dr Esteban-Cornejo will focus on the brain-related changes derived from a specific intervention physical activity-, relevant to patients with psychotic disorders. She will present cross-sectional data on a randomized controlled trial which has examined the effects of an exercise program on structural and functional neuroimaging, mental health outcomes and cognitive and academic performance. Finally, Dr Pina-Camacho will present data demonstrating how neuroimaging techniques may assist differential diagnosis, treatment choice or prognostic prediction during the early stages of psychosis, analogous to what is done routinely in other areas of medicine. Despite the fact that research in child and adolescent mental health has been underscored as a chief priority by leading health organizations, understanding of the pathophysiological mechanisms of neuropsychiatric disorders occurring during youth is still limited. Furthermore, translation of advances in biology to clinical care is hampered by difficulties in linking basic and clinical research ventures. The Asociación de Científicos en Salud Mental del Niño y Adolescente - Fundación Alicia Koplowitz aims to overcome such shortcomings by facilitating joint initiatives between its members and sharing its translational efforts with the neuroscientific community. Unlike neurological disorders, which involve cell death in most instances, psychiatric disorders are “connectopathies” resulting in an abnormal function of brain circuits without neuronal loss. Their study requires the use of specific experimental models assessing neuronal and population activity, such as those shown in the first presentation. The second presentation will appeal to an audience ranging from basic neuroscientists interested in striatal and sensory pathways, computational neuroscientists interested in learning algorithms, to clinical neuroscientists focused on applied research into the mechanisms of neuropsychiatric illness. The third presentation aims to inform on the neurobiological changes derived from a psychosocial intervention which is commonly put in place in patients with psychotic disorders, yet lacks evidence-base so far. The final presentation will interrogate if and how biological data can assist clinicians in delivering care. Understanding the actual translational value of neuroscience-based approaches to the study of neurodevelopmental conditions such as psychosis should be a primary focus for both neuroscientists and clinicians.

Speakers

1. 2. 3. 4.

Francesc Artigas PhD. Institut d’Investigacions Biomèdiques de Barcelona, CSICIDIBAPS Guillermo Horga MD, PhD. Columbia University, New York, USA. Irene Esteban-Cornejo, PhD. University of Granada. Laura Pina-Camacho MD, PhD. Child and Adolescent Psychiatry Department, Hospital General Universitario Gregorio Marañón, IiSGM, School of Medicine, Universidad Complutense, CIBERSAM, Madrid, Spain

Contact:

Francesc Artigas. [email protected]

Session:

Symposium


SPEAKER 1

Code

SY13

- 62 -

Abstracts: Symposia


Title:

Disrupton of cortical activity by psychotogenic agents

Speaker

Francesc Artigas PhD

Abstract

F. Artigas, A. Castañé, M. S. Riga, L. Lladó-Pelfort, E. Troyano-Rodríguez, H E Van den Munkhof, N. Santana, P. Celada Systems Neuropharmacology Group, Institut d’Investigacions Biomèdiques de Barcelona, CSICIDIBAPS, CIBERSAM. The pathophysiology of schizophrenia is poorly known. Experimental models attempt to mimic schizophrenia symptoms. In particular, psychotomimetic agents evoke perceptual, affective and cognitive changes that are useful to understand the neurobiology of psychotic disorders. Here we review preclinical research examining the effects of non-competitive NMDA-R antagonists and serotonergic hallucinogens (preferential 5-HT2A-R agonists) on cortical activity. NMDA-R antagonists, such as phencyclidine (PCP), and serotonergic hallucinogens (DOI, 5-MeODMT) exert common actions in the prefrontal cortex (PFC) of anesthetized rodents. These agents alter pyramidal neuron activity (with an overall increase in discharge) and reduce low frequency oscillations (0.15-4 Hz). PCP actions involve the preferential blockade of NMDA-R in GABAergic neurons of the reticular thalamus, and the subsequent bottom-up increase in thalamocortical activity. However, the action of serotonergic hallucinogens appears to be cortically-based. The disruption of PFC activity induced by all these agents is reversed by antipsychotic drugs, which suggests its association with psychotic symptoms. In awake, freely-moving mice, 5-MeO-DMT markedly alters oscillatory activity in cortical areas (PFC and V1) and in the mediodorsal thalamus (MD). The change in V1 is consistent with the visual hallucinatory activity of 5-MeO-DMT. More marked effects (power increase in all bands) were seen in mice lacking 5-HT2A-R which, together with pharmacological studies, suggests the additional involvement of 5-HT1A-R in the psychotogenic actions of 5-MeO-DMT. On the other hand, early postnatal treatment of rats with PCP induces long-lasting changes in brain oscillatory activity, mainly characterized by an increase in beta and gamma powers in ventral hippocampus (vHPC) and a marked decrease in vHPC-PFC coherence. These alterations may account for the short-term memory deficits observed in the novel object recognition test during adolescence. Overall, these studies suggest an association of psychotic symptoms with disrupted cellular/ population activity in PFC, also involving other anatomically-related areas, such as V1 and MD. Work supported by grants from Instituto de Salud Carlos III (PI09/1245, PI12/00156 and PI16/00287 (PN de I+D+I 2008-2011, ISCIII-Subdirección General de Evaluación y Fomento de la Investigación cofinanced by the European Regional Development Fund. “Una manera de hacer Europa”)), Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM P82, 11INT3) and Fundación Alicia Koplowitz. MR was supported by an IDIBAPS fellowship.

Recent publications

1. 2. 3.

Troyano-Rodríguez E, Lladó-Pelfort L, Santana N, Teruel Martí V, Celada P, Artigas F (2014) Phencyclidine inhibits the activity of thalamic reticular gamma-aminobutyric acidergic neurons in rat brain. Biol Psychiatry 76:937-945 Riga MS, Bortolozzi A, Campa L, Artigas F, Celada P (2016) The serotonergic hallucinogen 5methoxy-N,N-dimethyltryptamine disrupts cortical activity in a regionally-selective manner via 5- HT1A and 5-HT2A receptors. Neuropharmacology 101:370-8 .Lladó-Pelfort L, Troyano-Rodriguez E, Van den Munkhof HE, Cervera-Ferri A, Jurado N, Núñez- Calvet M, Artigas F, Celada P (2016) Phencyclidine-induced disruption of oscillatory activity in prefrontal cortex: Effects of antipsychotic drugs and receptor ligands. Eur Neuropsychopharmacol 26(3):614-25

Session:

Symposium

Title:

Predictive-coding mechanisms of psychosis

Speaker

Guillermo Horga MD, PhD

Abstract

G. Horga1, C. M. Cassidy1, S. C. Baker1, A. Abi-Dargham2 1. New York State Psychiatric Institute, Columbia University Medical Center, New York, New York, USA 2. Stony Brook University, Stony Brook, New York, USA

SPEAKER 2

Code

SY13

Predictive-coding and related models of perceptual inference provide a unifying framework to www.congreso-senc.com

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Abstracts: Symposia


understand the integration of anticipatory expectations into perception. At the core of these models is the assumption that the brain is an inference machine that learns environmental regularities to form an internal model of the world, an internal model that can serve to efficiently anticipate, process and interpret sensory events but that can also bias perception. Modern models of psychosis have proposed that abnormalities in predictive computations could explain the perceptual disturbances (i.e., hallucinations) and delusional beliefs (i.e., delusions) that characterize this clinical syndrome, although empirical evidence in this respect has been incomplete. Methods: Here, I will present recent data that supports the notion that abnormalities in predictive coding may be a core deficit in psychosis and that this deficit may relate to other well-established neural phenotypes of psychosis, such as the striatal dysregulation in dopamine release consistently observed in psychosis. Results: I will present recent functional magnetic resonance imaging (fMRI) data suggesting that patients with active auditory hallucinations display an abnormality in predictive-coding signals in voice-sensitive regions of the auditory cortex. I will also present resting-state fMRI and molecular positron emission tomography (PET) imaging data suggesting that a disruption in functional connectivity between the striatum and associative cortices, including some areas of the auditory cortex, is related to dopamine function and psychosis. Finally, behavior during an interval reproduction task and PET imaging data before and after an amphetamine challenge suggest that striatal dopamine release is specifically linked to context-related modulations of subjective perception under uncertainty. Conclusions: These recent findings agree with predictive coding models of psychosis and may shed new light on the neurobiological and computational mechanisms of psychosis. Recent publications

1. 2. 3.

Abi-Dargham A, Horga G. The search for imaging biomarkers in psychiatric disorders. Nat Med. 2016 Nov;22(11):1248-1255. Horga G, Cassidy CM, Xu X, Moore H, Slifstein M, Van Snellenberg JX, Abi-Dargham A. Dopamine- Related Disruption of Functional Topography of Striatal Connections in Unmedicated Patients With Schizophrenia. JAMA Psychiatry. 2016 Aug 1;73(8):862-70. Horga G, Schatz KC, Abi-Dargham A, Peterson BS. Deficits in predictive coding underlie hallucinations in schizophrenia. J Neurosci. 2014 Jun 11;34(24):8072-82.

Session:

Symposium

Title:

The effects of physical exercise on brain function: mental health, cognition and academic performance. Cross-sectional results of the ActiveBrains project.

Speaker

Irene Esteban-Cornejo, PhD

SPEAKER 3

Code

SY13


1.

Esteban-Cornejo I, Martinez-Gomez D, Gómez-Martínez S, del Campo-Vecino J, FernándezSantos J, Castro-Piñero J, Marcos A, Veiga OL. Inflammatory biomarkers and academic performance in youth. The UP&DOWN Study. Brain Behav Immun. 2016 May;54:122-7.

2.

Esteban-Cornejo I, Tejero-González C, Martínez-Gómez D, Del-Campo J, González-Galo A, Padilla- Moledo C, Sallis JF, Veiga OL. Independent and combined influence of the components of physical fitness on academic performance in youth. J Pediatr. 2014 Aug;165(2):306-312

3.

Esteban-Cornejo I, Hallal PC, Mielke GI, Menezes AM, Gonçalves H, Wehrmeister F, Ekelund U, Rombaldi AJ. Physical Activity throughout Adolescence and Cognitive Performance at 18 Years of Age. Med Sci Sports Exerc. 2015 Dec;47(12):2552-7.

Session:

Symposium

Title:

Biomarkers for psychotic disorders: translating research into clinical utility

Speaker

Laura Pina-Camacho MD, PhD

Abstract

Pina-Camacho L1,2 1 Institute of Psychiatry Psychology Neuroscience, King’s College London, London, UK 2 Hospital General Universitario Gregorio Marañón, IiSGM, School of Medicine, Universidad Complutense, CIBERSAM, Madrid, Spain


SPEAKER 4

Code

SY13

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Abstracts: Symposia

To discuss how neuroimaging techniques may assist differential diagnosis, treatment choice or prognostic prediction during the early stages of psychosis, analogous to what is done routinely in other areas of medicine. The first part of this review will present evidence on the presence of neuroanatomical alterations in psychoses. It will then discuss studies that have examined the relationship between brain alterations and various medium- to long-term clinical and functional outcomes. MRI techniques have suggested that neuroanatomical biomarkers can be used for direct clinical benefits. For example, MRI data obtained at illness onset have been used to predict, with significant accuracy, whether a specific individual is likely to experience remission of symptoms or treatment response. Besides, these tools have helped gain new fundamental insights into the pathophysiology of these complex conditions. Findings suggest that clinical prediction in psychiatry (including prediction of diagnosis or illness outcomes requires a combination of multiple measurements from different sources. Among these sources, MRI techniques could prove promising in the search for sensitive and specific biomarkers across psychotic disorders. From there, these tools might (i) assist clinicians in the process of differential diagnosis, treatment choice or in supporting prognostic statements at early stages of psychosis, (ii) help refine current diagnostic classification systems, and (iii) impact disease management as they raise the possibility that interventions that target the commonly affected brain regions/networks may prove helpful across psychopathology. Until then, it seems that current psychosis classification systems should continue to be based on traditional nosology for the purpose of clinical work, while the research on the underlying biological mechanisms should explore the use of transdiagnostic approaches (e.g. across psychotic disorders). Recent publications

1.

Pina-Camacho L., García-Prieto J., et al (2015). Predictors of Schizophrenia Spectrum Disorders in Early-onset First Episodes of Psychosis: A Support Vector Machine Model. European Child and Adolescent Psychiatry 24:427–440

2.

Pina-Camacho L, et al. Age at first episode modulates diagnosis-related structural brain abnormalities in psychosis. Schizophr Bull. 2016 Mar;42(2):344-57.

3.

Fraguas D, Janssen J, Pina-Camacho L, Diaz-Caneja CM, Arango C. Progressive brain changes in children and adolescents with early onset psychosis: a meta-analysis of longitudinal MRI studies. Schiz Research. 2016; 173(3):132-9.


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Abstracts: Symposia

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Symposium SY14. Intellectual Disability: New Opportunities for Understanding the Neurobiology and Advancing Therapy


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Abstracts: Symposia


Session:

Symposium

Title:

Intellectual Disability: New Opportunities for Understanding the Neurobiology and Advancing Therapy

Chairperson

Mara Dierssen

OVERALL ABSTRACT

Code

SY14


Speakers

In recent years, intellectual disability in neurodevelopmental disorders has been found to be manageable to some extent through behavioral stimulation and pharmacological intervention, improving the quality of life in patients. Preclinical models of Down syndrome or fragile X syndrome have revealed some of the neurobiological mechanisms involved in the improved cognitive performance after therapeutic intervention. This symposium will cover the most recent advances at clinical and preclinical levels in intellectual disability treatment. The impact of behavioral and pharmacological interventions on cognition will be evaluated in targeted clinical studies, and through proteomics, in vivo electrophysiology, and behavioral approaches in preclinical models. All together, the symposium will illustrate the most recent advances in clinical approaches to treat intellectual disability together with the translational potential of preclinical models for neurodevelopmental disorders. The speakers will present the recent advances, challenges and diagnosis/therapeutic implications of genomic structural and functional variation in brain systems related to cognition and disease-related dysfunction, focusing on both mouse and human studies. The topic of this symposium is of broad interest for the neuroscience community, because it tackles new concepts in neurogenomics, that is, how the genome as a whole contributes to a neurodevelopmental cognitive disorders, such as DS or FXS, and thus to the development, structure and function of the nervous system. We will discuss network genetics, engineered mouse models, neuronal network dynamics and computational modeling and applications of new therapeutics to human cognitive phenotypes. 1. 2. 3. 4.

Maria Victoria Puig Velasco. Hospital del Mar Medical Research Institute, Barcelona Biomedical Research Park Andrés Ozaita Mintegui. Universitat Pompeu Fabra Mara Dierssen. Center for Genomic Regulation Rafael de la Torre Fornell. Hospital del Mar Medical Research Institute

Contact:

Mara Dierssen. [email protected]

Session:

Symposium

Title:

Alterations of prefronto-hippocampal neural network dynamics underlie cognitive impairment in behaving mice models of intellectual disability

Speaker

Maria Victoria Puig Velasco

Abstract

Mv. Puig 1, M. Alemany 1, T. Gener 1 1. Hospital del Mar Medical Research Institute, Barcelona Biomedical Research Park, 08003 Barcelona, Spain

SPEAKER 1

Code

SY14

We aim at understanding the neural substrates of cognitive impairment to find new strategies for cognitive amelioration. We leverage on mouse models of intellectual disability, specifically Down syndrome (DS) and schizophrenia. We record neural activity in the prefrontal cortex (PFC) and hippocampus (HPC) of freely-moving mice performing cognitive tasks and evaluate the actions of selective drugs on PFC and HPC neural dynamics and PFC-HPC connectivity. Trisomic Ts65Dn mice, a well-established model of DS and cognitive impairment, show disrupted PFC delta (4 Hz) and theta (8 Hz) oscillations and exacerbated HPC theta. These abnormalities are aggravated during novel object recognition (NOR), a memory task with PFC-HPC demand. NOR is associated with increased theta and beta (18-25 Hz) in HPC and elevated PFC-HPC theta connectivity in normal mice. DS mice show deficits in NOR memory that are associated with exacerbated theta in PFC and HPC and deficient PFC-HPC theta connectivity. One month of treatment with the cognitive enhancer EGCG, the main compound of green tea, normalizes PFC delta and theta activity but not HPC theta. Ongoing work investigates its actions in NOR memory. www.congreso-senc.com

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Abstracts: Symposia


The schizophrenia study aims at unravelling the neural substrates of cognitive impairment mediated by acute antipsychotics. Specifically, we have investigated the role of the serotonin system (5-HT1AR and 5-HT2AR) in the actions of atypical (clozapine, risperidone) vs. typical (haloperidol) antipsychotics on PFC-HPC neural dynamics. We report that spiking activity, theta and high gamma (50-80 Hz) oscillations are reduced by acute antipsychotics and the 5-HT1AR agonist 8-OH-DPAT both in PFC and HPC. In addition, antipsychotics exacerbate delta oscillations. Additionally, all compounds disrupt PFCHPC connectivity at theta. Ongoing work evaluates the impact of these compounds during NOR memory. Taken together, our findings suggest that abnormal theta activity in PFC and HPC and PFC-HPC theta connectivity underlie NOR memory impairment. Recent publications

1. 2. 3.

Serotonin Modulation of Prefronto-Hippocampal Rhythms in Health and Disease. Puig MV, Gener T. ACS Chem Neurosci. Jul 15;6(7):1017-25. 2015 Prefrontal dopamine in associative learning and memory. Puig MV, Antzoulatos EG, Miller EK. Neuroscience. 282:217-29. 2014 Serotonin modulation of cortical neurons and networks. Celada P, Puig MV, Artigas F. Front Integr Neurosci. 7:25. 2013

Session:

Symposium

Title:

The endocannabinoid system as a pharmacological target for intellectual disability disorders

Speaker

Andrés Ozaita Mintegui

Abstract

A. Ozaita Universitat Pompeu Fabra, Barcelona, Spain

SPEAKER 2

Code

SY14

Intellectual disability disorders include a number of genetically derived malfunctions without specific therapy. Preclinical models of these disorders have been fundamental for understanding the pathophysiological processes affected, and also for developing and testing potential therapeutic approaches. Fragile X syndrome (FXS) is a rare disorder that constitutes the most common cause of hereditary intellectual disability. This monogenetic disorder derives from the silencing of the FMR1 gene. Our group has described the possibility to improve cognitive performance in the Fmr1 knockout mouse (Fmr1KO), a model for FXS, by targeting the endocannabinoid system. At the central level, the endocannabinoid system regulates synaptic homeostasis and signaling pathways relevant for cognition. Specifically, we found that pharmacological or genetic targeting of the main cannabinoid receptor in the brain, the cannabinoid type 1 (CB1) receptor, improves cognitive performance and other traits of the disorder such as reduced nociception or epilepsy susceptibility. We have assessed low doses of the CB1 receptor antagonist, far below those doses described to produce psychiatric adverse effects in anti-obesity clinical settings. We found that the low-dose treatment was equally effective when testing episodic memory in the novel object recognition task. In addition, electrophysiological analysis of hippocampal slices from Fmr1KO-treated mice revealed the normalization of the aberrant mGluR5-dependent longterm depression (mGluR5-LTD) characteristic of the FXS model. At the molecular level, and using an unbiased transcriptomic approach on hippocampal synaptoneurosomal samples, we found the normalized expression of a number of mRNAs relevant for synaptic plasticity in Fmr1KO-treated mice. All together, our findings point to a beneficial effect of targeting the endocannabinoid system in FXS. Future studies are warranted to address the best approaches to reduce CB1 receptor activity as well as to explore whether other intellectual disability disorders may benefit of this therapeutic approach. Funding: MINECO/FEDER (BFU2015-68568-P) and ICREA Acadèmia. Recent publications

1.

2. 3.


Possible Therapeutic Doses of Cannabinoid Type 1 Receptor Antagonist Reverses Key Alterations in Fragile X Syndrome Mouse Model. Gomis-González M, Busquets-Garcia A, Matute C, Maldonado R, Mato S, Ozaita A.. Genes (Basel). 7(9). pii: E56. 2016 New insights into the molecular pathophysiology of fragile X syndrome and therapeutic perspectives from the animal model. Busquets-Garcia A, Maldonado R, Ozaita A. Int J Biochem Cell Biol. 2014 Aug;53:121-6. Targeting the endocannabinoid system in the treatment of fragile X syndrome. Busquets-Garcia A, Gomis-González M, Guegan T, Agustín-Pavón C, Pastor A, Mato S, Pérez-Samartín A, Matute C, de la Torre R, Dierssen M, Maldonado R, Ozaita A. Nat Med. 19(5):603-7. 2013 - 69 -

Abstracts: Symposia


Session:

Symposium

Title:

New plasticity targeted therapies for intellectual disability

Speaker

Mara Dierssen

Abstract

Mara Dierssen 1Cellular & Systems Neurobiology, Systems Biology Program, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona

SPEAKER 3

Code

SY14

Down syndrome (DS) is the most common genetic cause of mental retardation. In DS individuals and trisomic mice models early intervention results in only limited and temporary cognitive improvements. Our previous work in trisomic mice suggested that this is probably due to an inability to translate the temporary changes in synaptic efficiency after exposure to enriched environments, into stable structural changes. Several molecular mevchanisms may account for these alterations but not all are good therapeutic targets. I will discuss the experimental arguments that make one of the triplicated genes in DS a good pharmacological target for boosting plasticity: Dyrk1A a candidate gene closely implicated in various DS features. Dyrk1A encodes for a serine/threonine kinase and phosphorylates several nuclear and cytoplasmatic substrates. It has been shown that Dyrk1A is involved in embryonic neurogenesis and neuronal differentiation and we have demonstrated previously that it can boost activity-dependent plasticity. However, I will also discuss how modeling strategies can help determining if the network topological changes produced by environment in a DS model without treatment and upon environmental enrichments lead to a more proficient system Funding: This work was supported by the Spanish Ministry of Economy and Competitiveness, ‘Centro de Excelencia Severo Ochoa 2013-2017’, the ‘CERCA Programme / Generalitat de Catalunya’ and the CIBER of Rare Diseases. and Jerome Lejeune Foundation Recent publications

Catuara-Solarz S, Espinosa-Carrasco J, Erb I, Langohr K, Gonzalez JR, Notredame C, Dierssen M. Combined Treatment With Environmental Enrichment and (-)-Epigallocatechin-3-Gallate Ameliorates Learning Deficits and Hippocampal Alterations in a Mouse Model of Down Syndrome. eNeuro. 3(5). 2016 Ruiz-Mejias M, Martinez de Lagran M, Mattia M, Castano-Prat P, Perez-Mendez L, Ciria-Suarez L, Gener T, Sancristobal B, García-Ojalvo J, Gruart A, Delgado-García JM, Sanchez-Vives MV, Dierssen M. Overexpression of Dyrk1A, a Down Syndrome Candidate, Decreases Excitability and Impairs Gamma Oscillations in the Prefrontal Cortex. J Neurosci. 36(13):3648-59. 2016 Dierssen M. Down syndrome: the brain in trisomic mode. Nat Rev Neurosci. 13(12):844-58. 2012

Session:

Symposium

Title:

Tracking response to pharmacological and non-pharmacological interventions in intellectual disabilities: limitations and future perspectives

Speaker

Rafael de la Torre Fornell

Abstract

Rafael de la Torre Fornell1, Mara Dierssen2 1Hospital del Mar Medical Research Institute (IMIM), Barcelona, Spain 2Center for Genomic Regulation (CRG), Barcelona, Spain

SPEAKER 4

Code

SY14

Advances in understanding molecular and synaptic mechanisms of ID in Fragile X (FXS) and Down (DS) syndromes through animal models have led to targeted controlled trials with pharmacological agents designed to normalize these underlying mechanisms and find molecular targets to improve clinical outcomes. However, several clinical trials have failed to demonstrate efficacy of these targeted treatments to improve surrogate behavioral/cognitive endpoints. These failures relate to the difficulties in establishing: (i)The lack of generally accepted endpoints to assess improvement in function in individuals with intellectual disability. (ii)Individual variability in intellectual disability at several levels (genetic (genetic polymorphisms, such www.congreso-senc.com

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Abstracts: Symposia

as DA, 5-HT, APOE), biochemical (Aβ-peptides), physiological (sleep disorders), medical comorbidities (hypothyroidism, depression), sociodemographic characteristics (gender), or life style (diet). Those differences may also modulate the response to treatment and may lead to unresponsive, responsive patients or even to individual-specific adverse events. Previous pre-clinical and clinical data suggest that non-pharmacological treatments combine with pharmacological ones showing overall more sustained effects when treatments are discontinued. This will be the case of cognitive training already assayed in DS and may be in the future the inclusion of neuromodulation techniques in clinical trials. In conclusion, ID individuals might not show similar response to the same pharmacological treatment, and therefore cannot be directly compared to one another, which is an important consideration for establishing drug efficacy in clinical trials because. We need to redefine primary end-points to assess improvement in function in individuals with ID and consider the factors, which explain part of the phenotype variability. Non-pharmacological treatments in the future will be companions of pharmacological ones. Recent publications

1.

2.

3.


VNTR-DAT1 and COMTVal158Met Genotypes Modulate Mental Flexibility and Adaptive Behavior Skills in Down Syndrome. Del Hoyo L, Xicota L, Langohr K, Sánchez-Benavides G, de Sola S, Cuenca- Royo A, Rodriguez J, Rodríguez-Morató J, Farré M, Dierssen M, de la Torre R; Front Behav Neurosci. 10:193. 2016 Safety and efficacy of cognitive training plus epigallocatechin-3-gallate in young adults with Down's syndrome (TESDAD): a double-blind, randomised, placebo-controlled, phase 2 trial. de la Torre R, de Sola S, … Delabar JM, Dierssen M; TESDAD study group. Lancet Neurol. 15(8):801-10. 2016 Semantic Verbal Fluency Pattern, Dementia Rating Scores and Adaptive Behavior Correlate With Plasma Aβ42 Concentrations in Down Syndrome Young Adults. Hoyo LD, Xicota L, Sánchez- Benavides G, Cuenca-Royo A, de Sola S, Langohr K, Fagundo AB, Farré M, Dierssen M, de la Torre R. Front Behav Neurosci. 9:301. 2015

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Abstracts: Symposia

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Symposium SY15. Neural cell fate determinants during cortical development in health and disease


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Abstracts: Symposia

Session:

Symposium

Title:

Neural cell fate determinants during cortical development in health and disease

Chairperson

Ismael Galve-Roperh

OVERALL ABSTRACT

Code

SY15


Our symposium covers the timely theme of neuronal progenitors in the developing brain and their alteration in cortical malformations and disease. We will focus on the intrinsic mechanisms that regulate the generation, migration and maturation of cortical neurons during development, and how alterations of these mechanisms lead to diseases impairing brain function, particularly epilepsy. Recent advances in this field have identified networks of transcription factors and epigenetic mechanisms that finely regulate neurogenesis and neural circuit formation. Studies in the developing mouse suggest that the compromised integrity of RG cells (Cappello) and alteration of stereotyped patterns of gene expression (De Juan) may underlie cortical malformations. On the other hand, niche-derived extracellular signals and synaptic function are emerging as central regulators of progenitor proliferation and maturation with key roles in the emergence of epilepsy (Galve-Roperh, Represa). In this symposium we will discuss emerging concepts about the molecular regulation of brain progenitor cells and neurogenesis (De Juan, Galve-Roperh). Presentations will discuss emerging concepts on the regulation of neurogenesis and cortical development (De Juan), followed by recent advances on the role of CB1 receptors and endogenous cannabinoid signaling for appropriate cortical neuron migration (Galve-Roperh). Then we will present recent advances on the neurodevelopmental basis of refractory epilepsy and the potential therapeutic opportunities currently under scrutiny (Capello, Represa). In addition, new studies using 3D cerebral organoids to address the central topic of the symposium will be a methodological highlight of the session. During cortical development the generation of the appropriate number of neurons, their final position, differentiation and connectivity is controlled by the complex integration of intrinsic neurogenic determinants and extrinsic niche-derived signals. Alterations of these key neurodevelopmental processes have a dramatic impact in adult brain function that are responsible for cognitive and affective disorders. Neurodevelopmental diseases are also frequently associated to refractory epilepsy. Understanding the molecular mechanisms regulating neuronal development is therefore crucial to unravel the ethiopathology of these devastating nervous system disorders. This symposium on intrinsic molecular determinants of neurogenesis, neuronal migration and differentiation will be of interest to the broad community of Spanish neuroscience, from developmental neurobiologists to electrophysiologists and systems neuroscientists interested in neural circuit signaling, plasticity, and the emergence of brain disease and epilepsy.

Speakers

1. 2. 3. 4.

Meuri del Camino De Juan Romero. Instituto de Neurociencias, Alicante Ismael Galve-Roperh. Complutense University-CIBERNED Silvia Cappello. Max Planck Institute for Psychiatry Alfonso Represa. INMED, Institut de Neurobiologie de la Méditerranée

Contact:

Ismael Galve-Roperh. [email protected]

Session:

Symposium

Title:

Genetic control of neurogenesis and cerebral cortex expansion

Speaker

Meuri del Camino De Juan Romero

Abstract

C. de Juan Romero 1, P. Mullet 1, V. Borrell 1 1 Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas - Universidad Miguel Hernández, 03550 Sant Joan d’Alacant, Spain

SPEAKER 1

Code

SY15

In higher mammals with highly complex brains, cortical expansion further involves the formation of folds and fissures. This evolutionary expansion of the neocortex is thought to be based on differences in the abundance of bRGCs. In order to expand the progenitor populations specifically in a restricted region, in utero electroporation of conserved genes such as Ccnd1, Cdk4, Trnp1, PDGFD, Pax6, FLTR3 or the human-specific gene ARHGAP11B, has been performed showing an increased number of bRGs. In the ferret cortex, some of the genes found to be differentially-expressed between prospective gyrus www.congreso-senc.com

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Abstracts: Symposia


and sulcus, show modular gene expression (de Juan Romero et al 2015). One of them is Eomes, a transcription factor which expression in the OSVZ is has been shown to correlate with the location of folds and fissures. To determine the role of Eomes in cortical folding, we have performed overexpression by in utero electroporation at several developmental time points. At early stages, we have seen an increase in progenitor proliferation whereas at postnatal stages overexpression of Eomes leads to changes in the convolution pattern. This results show not only the important role of progenitor cells in the expansion of the cortex but also the strong genetic regulation of the neocortical growth and folding by genes such as Eomes. Recent publications

1. 2. 3.

Martínez-Martínez M, De Juan Romero C, Fernández V, Cárdenas A, Götz M, Borrell V (2016) A restricted period for formation of outer subventricular zone defined by Cdh1 and Trnp1 levels. Nat Comm 7:11812 (DOI: 10.1038/ncomms11812). De Juan Romero C, Bruder C, Martínez-Martínez M, Tomasello U, Sanz-Anquela JM, Borrell V (2015) Discrete domains of gene expression in germinal layers distinguish the development of gyrencephaly. EMBO J 34:1859-1874. De Juan Romero C, Borrell V (2015) Coevolution of Radial Glial Cells and the Cerebral Cortex. Glia 63:1303-1319.

Session:

Symposium

Title:

Neurodevelopmental cannabinoid signaling in cortical development

Speaker

Ismael Galve-Roperh

Abstract

A. de Salas-Quiroga, D. García-Rincón, J. Paraíso, J. Díaz-Alonso, I. Galve-Roperh1 1. Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED),Spain; 2. School of Biology, Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS) and Instituto Universitario de Investigaciones Neuroquímicas (IUIN), Complutense University, Madrid, Spain

SPEAKER 2

Code

SY15

Nowadays it is known that the endocannabinoid system plays a regulatory role of various neurodevelopmental processes. CB1 cannabinoid receptor signalling regulates neural progenitor proliferation, identity, and neuronal differentiation. We recently showed that acute CB1 loss of function leads to an arrest of radial migration and the formation of subcortical heterotopias. These mice exhibit increased pentylenetetrazole-induced seizures (PTZ) in adulthood. Loss of CB1 receptor function led to an abnormal accumulation of the RhoA protein in newborn pyramidal neurons, indicating that CB1 signalling promotes proteasomal degradation of RhoA. Noteworthy RhoA knockdown in vivo rescued the migration arrest and seizure susceptibility induced by developmental ablation of the CB1 receptor. siCB1-induced migration arrest was associated to an impairment on the multipolar to bipolar neuronal transition, and was also reproduced by Cre-mediated ablation in CB1 floxed mice or upon shCB1 electroporation. Thus, transient embryonic CB1 loss of function induces neuronal circuit hyperexcitability, although the exact contribution of neuronal heterotopias or its interaction with the normotopic cortex to epilepsy is subject of debate. Ongoing studies using chemogenetic manipulation by DREADD receptors in mispositioned cells aim to dissect the contribution of the normotopic and heteropic cortex to the epileptiform activity. Finally, characterization of samples derived from palliative surgery of focal cortical dysplasia patients with intractable epilepsy indicate altered endocannabinoid signalling and expression. Altogether, the above-mentioned evidence supports a fundamental role of CB1R during brain development, in particular by controlling pyramidal neuron radial migration and their proper integration into cortical networks. Our data suggest that a compromised developmental CB1R function -upon prenatal exposure to cannabinoids or genetic variations- can deeply affect brain excitability, which may in turn contribute to migration neurodevelopmental disorders. This work has been supported by the Instituto de Salud Carlos III (Plan Estatal de I+D+i 2013-2016) grant PI15-00310 to IGR, and cofunded by the European Regional Development Fund (ERDF) “A way to achieve Europe”. Recent publications

1.

2. www.congreso-senc.com

Díaz-Alonso, J.; de Salas-Quiroga, A., Garcez, P.P., Parsons, M., Andradas, C., Paraíso-Luna, J., García-Rincón, D., Sánchez, C., Guillemot, F., Guzmán, M., Galve-Roperh, I (2016) Loss of cannabinoid CB1 receptors induces cortical migration malformations and increases seizure susceptibility. Cerebral Cortex doi:10.1093/cercor/bhw309 (in press). Díaz-Alonso J, Aguado T, de Salas-Quiroga A, Ortega Z, Guzmán M, Galve-Roperh I (2014) - 75 -

Abstracts: Symposia


3.

CB1 Cannabinoid Receptor-Dependent Activation of mTORC1/Pax6 Signaling Drives Tbr2 Expression and Basal Progenitor Expansion in the Developing Mouse Cortex. Cereb Cortex. 25:2395-2408. Díaz J, Aguado T., Wu C., Palazuelos, J., Hofmann, C., Garcez, P., Guillemot, F., Lu, H.C., Lutz, B., Guzmán, M., Galve-Roperh, I. (2012) CB1 cannabinoid receptors drive corticospinal motor neuron specification through the Ctip2/Satb2 transcriptional regulation axis. Journal of Neuroscience 32:16651-16665.

Session:

Symposium

Title:

Modeling neuronal migration disorders with human derived cerebral organoids

Speaker

Silvia Cappello

Abstract

Silvia Cappello, Max-Planck-Institute of Psychiatry, Munich, Germany

SPEAKER 3

Code

SY15

Malformations of the human neocortex are present in about 1% of the general population and represent a major cause of developmental disabilities including severe epilepsy. To date, mouse lines carrying mutations of genes so far identified in human patients with cortical malformations only partially recapitulate the expected cortical phenotypes and therefore do not provide reliable models to entirely understand the molecular and cellular mechanisms responsible for these disorders. Here we use induced pluripotent stem cells and derived cerebral organoids from patients with mutations in the cadherin receptor-ligand pair FAT4 and DCHS1 to study periventricular heterotopia. Our results show that we can reproduce the cortical heterotopia in cerebral organoids, validating this model as excellent system to study these disorders. Mutations in FAT4 and DCHS1 cause changes in the morphology of neural stem cells and result in defective neuronal migration dynamics in a subset of neurons.Taken together these results suggest that defective radial glia morphology and an altered navigation system in a subset of neurons underlie this form of periventricular heterotopia. Recent publications

1.

2. 3.

Cappello S, Gray MJ, Badouel C, Lange S, Einsiedler M, Srour M, Chitayat D, Hamdan FF, Jenkins ZA, Morgan T, Preitner N, Uster T, Thomas J, Shannon P, Morrison V, Di Donato N, Van Maldergem L, Neuhann T, Newbury-Ecob R, Swinkells M, Terhal P, Wilson LC, Zwijnenburg PJ, Sutherland-Smith AJ, Black MA, Markie D, Michaud JL, Simpson MA, Mansour S, McNeill H, Götz M, Robertson SP (2013) Mutations in genes encoding the cadherin receptor-ligand pair DCHS1 and FAT4 disrupt cerebral cortical development. Nat Genet 45(11):1300-1308. Cappello S. (2013) Small Rho-GTPases and cortical malformations: fine-tuning the cytoskeleton stability. Small GTPases 4(1):51-56. Cappello S, Böhringer CR, Bergami M, Conzelmann KK, Ghanem A, Tomassy GS, Arlotta P, Mainardi M, Allegra M, Caleo M, van Hengel J, Brakebusch C, Götz M (2012) A radial gliaspecific role of RhoA in double cortex formation. Neuron 73(5):911-924.

Session:

Symposium

Title:

Neuropathological Basis of Epilepsy in Cortical Development Disorders and therapeutic vistas

Speaker

Alfonso Represa

SPEAKER 4

Code

SY15


1.

2.


Lozovaya N, Gataullina S, Tsintsadze T, Tsintsadze V, Pallesi-Pocachard E, Minlebaev M, Goriounova NA, Buhler E, Watrin F, Shityakov S, Becker AJ, Bordey A, Milh M, Scavarda D, Bulteau C, Dorfmuller G, Delalande O, Represa A, Cardoso C, Dulac O, Ben-Ari Y, Burnashev N (2014) Selective suppression of excessive GluN2C expression rescues early epilepsy in a tuberous sclerosis murine model. Nat Commun 5:4563. Salmi M, Bruneau N, Cillario J, Lozovaya N, Massacrier A, Buhler E, Cloarec R, Tsintsadze T, Watrin F, Tsintsadze V, Zimmer C, Villard C, Lafitte D, Cardoso C, Bao L, Lesca G, Rudolf G, Muscatelli F, Pauly V, Khalilov I, Durbec P, Ben-Ari Y, Burnashev N, Represa A, Szepetowski P (2013) Tubacin prevents neuronal migration defects and epileptic activity caused by rat Srpx2 silencing in utero. Brain 136(Pt 8):2457-2473.

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Posters


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Poster Topics s 1. Developmental Neurobiology

Page

81

2. Neuronal excitability, synapses and glia: cellular mechanisms 165 3. Systems Neuroscience

233

4. Cognitive and Behavioral Neuroscience

293

5. Theoretical and Computational Neuroscience

363

6. Disorders and nervous system repair

371

7. Homeostatic and neuroendocrine systems

539

8. New methods and technologies

549

9. History, Teaching, Release and Ethics (not received)

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10. Others

571


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Poster Topic s

1 .

Developmental Neurobiology


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CUX1 ENABLES CORPUS CALLOSAL CONNECTIONS OF LAYER II-III NEURONS BY REGULATING KV1-DEPENDENT FIRING

Fernanda M. Rodríguez-Tornos1*, Carlos G. Briz1*, Linnea A. Weiss1, Alvaro Sebastián-Serrano1,2, Saúl Ares1,3, Marta Navarrete4, Laura Frangeul5, Maria Galazo6, Denis Jabaudon5, José A. Esteban4 and Marta Nieto1. *Equal contribution. 1 Centro Nacional de Biotecnología (CNB-CSIC), Darwin 3, Campus de Cantoblanco, Madrid 28049, Spain. 2 Present address: Departamento de Bioquímica y Biología Molecular IV, Facultad de Veterinaria, Universidad Complutense de Madrid, Madrid, Spain. 3 Departamento de Matemáticas, Universidad Carlos III de Madrid, 28911 Leganés, Madrid, Spain, and Grupo Interdisciplinar de Sistemas Complejos (GISC). 4 Centro de Biología Molecular “Severo Ochoa”, Consejo Superior de Investigaciones Científicas (CSIC-UAM)), Madrid, 28049 Spain. 5 Department of Basic Neurosciences, University of Geneva, Geneva, Switzerland. 6HSCRB Harvard University, Cambridge MA.

Understanding the necessary coupling of intrinsic mechanisms of neuronal differentiation with activity is key to understand brain wiring. By investigating the mechanisms of corpus callosum formation we found evidences indicating that how each neuron fires selects its connectivity during cortical development (Rodríguez-Tornos et al., Neuron (2016) 89, (3), 494-506). These findings indicate that more attention should be paid on the electrical differentiation of neurons of the developing brain. Neuronal subtype specific transcription factors (TF) instruct key features of neuronal function and connectivity. Activity-dependent mechanisms also contribute to wiring and circuit assembly, but whether and how they relate to TF-directed neuronal differentiation is poorly investigated. We demonstrated that the TF Cux1 controls the formation of the layer II-III corpus callosum (CC) projections through the developmental transcriptional regulation of Kv1 voltage-dependent potassium channels and the resulting postnatal switch to a Kv1-dependent firing mode. Loss of Cux1 function led to a decrease in the expression of Kv1 transcripts, aberrant firing responses and selective loss of CC contralateral innervation but not of ipsilateral connections. Firing and innervation were rescued by re-expression of Kv1 or postnatal reactivation of Cux1 if performed during the postnatal window comprised between postnatal day (P) 8 and P11. Knocking-down Kv1 mimicked Cux1mediated CC axonal loss, also without eliminating ipsilateral projections. The data provides potential novel understanding of how ion channels, and excitability in general, are involved in mental disorders. The finding of a window of plasticity in which callosal axons can be repaired is relevant for therapeutic strategies targeting plasticity and supports the importance of understanding plasticity brakes. These findings reveal that activity-dependent processes are central bona fide components of neuronal TF-differentiation programs that establish a link between the regulation of firing and the selection of connectivity (in this case in local circuit versus both local and interhemispheric). Topic: 1. Developmental Neurobiology


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IMPLICATION OF RHOE IN OLIGODENDROCYTE DIFFERENTIATION AND MYELINATION PROCESS IN MICE M. P. Madrigal1, B. Ballester-Lurbe1, O. Gómez 2, J.M. Garcia-Verdugo3, I. Pérez-Roger1, J. Terrado2 1. Facultad de Ciencias de la Salud. Universidad CEU Cardenal Herrera. Valencia, Spain 2. Facultad de Veterinaria. Universidad CEU Cardenal Herrera. Valencia, Spain 3. Centro de Investigación Príncipe Felipe. Valencia, Spain

Myelination of central nervous system is a process carried out by oligodendrocytes, which form the myelin sheaths surrounding axons from embryogenesis to first stages of postnatal life. Each oligodendrocyte myelinates multiple segments in multiple axons and thus, the damage of a relatively small number of oligodendrocytes may result in alterations in axonal conduction, axonal loss and functional deficits. The aim of this work is to study the role of Rnd3/RhoE, a small GTPase constitutively active with pleiotropic roles in the central nervous system development, in myelination processes. We first analyzed RhoE expression in mice brain and we found that it was expressed in a subset of Sox10 positive oligodendrocytes throughout the striatum and the corpus callosum. To study the role of RhoE in myelination we analyzed the brains of postnatal mice that do not express RhoE (RhoEgt/gt). Our results show that the levels of Myelin Basic Protein and Myelin Oligodendrocyte Glycoprotein are reduced in RhoE gt/gt mice. In addition, the number of oligodendrocytes is reduced both in the striatum and in the corpus callosum, compared to their wild type littermates. Furthermore, the corpus callosum thickness is also thinner in RhoE null mice. Finally, we have studied by electron microscopy the myelination of corpus callosum axons and our results show the presence of inactive oligodendrocytes in the absence of RhoE. Moreover, myelin appeared less compacted and with reduced levels in the corpus callosum and striatum, of RhoEgt/gt mice. In summary, our results point out that the absence of RhoE protein produces a reduction in the levels of myelin in postnatal brains most probably due to the reduction in oligodendrocyte precursor cells. These data suggest that RhoE can be involved in important functions in the process of central myelination and it could play a role in the progression of demyelination and remyelination in the context of demyelinating diseases.

1. Developmental Neurobiology


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DEVELOPMENT OF THE THALAMIC NUCLEAR COMPLEX OF XENOPUS LAEVIS, BASED ON GENOARCHITECTURE

R. Morona1, S. Bandín2, N. Moreno1, J.M. López1, C. Muñoz-Sánchez1, N. Vidal1, N. Alfageme, D1. Lozano1, and A. González1 1 Dept. Cell Biology, Faculty of Biology, University Complutense of Madrid. Spain 2 Donders Institute for Brain Cognition and Behavior. Nijmegen. The Netherlands

In the early development of the alar plate of the diencephalic prosomere 2 (p2), which gives rise to the thalamus, the zona limitans intrathalamica plays a pivotal role in cell fate specification and regionalization. In the amphibian Xenopus laevis, as in anamniotes, the thalamus is first subdivided into a small rostral region (r-Th) expressing Nkx2.2 and Lhx1 and a large caudal region (c-Th) expressing Gbx2, Lhx2, Ngn2 and Dbx2. However, little is known about the molecular events that guide the late compartmentalization of these areas and the formation of the adult nuclear groups. We have studied the spatio-temporal correlation of the expression patterns of genes such as Gbx2, Lhx2, Ngn2 Nkx2.2 and Lhx2; together with the expression of neuronal markers (calbindin and calretinin). The combinatorial expression of these markers was used to reveal the events of the late development of the amphibian thalamus. During the larval development of Xenopus, after the establishment of the rostral and caudal thalamic progenitor domains, the c-Th is then subdivided in a c-Th1 (Dbx1+) and a c-Th2 (Ngn2+). Dbx1 is progressively reduced to the dorsocaudal area and c-Th2 occupied most of the caudal thalamus, which is then progressively stratified in three dorsoventral tiers (dorsal, intermediate, and ventral). The dorsal tier is reduced to the subhabenular area, the intermediate tier gives rise to most of the adult nuclei (central and lateral posteroventral) and the ventral tier is part of the classically considered lateral posteroventral nucleus. In turn, the rTh gives rise to the rostral and caudal subdivisions of the anterior nucleus, the lateral anterior nucleus, the intercalate geniculate leaflet, and a subpopulation of cells in the central nucleus. Our observations are largely similar to those described for comparable nuclei in other tetrapods and provides additional information for the thalamic organization in amphibians. Grant by: BFU201566041-P Topic: Developmental Neurobiology


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PHAGOCYTOSIS OF APOPTOTIC NEWBORN CELLS TRIGGERS A PRONEUROGENIC PROGRAM IN MICROGLIA

A.Sierra 1,2,3 , I. Diaz-Aparicio 1,3, V. Sánchez-Zafra 1,3, I. Paris 1,3, B. Sperlagh 4, A. Schulz 5, G. Lemke 6, J. Valero 1,2 1 . Achucarro Basque Center for Neuroscience, Leioa, Bizkaia 2 . Ikerbasque Foundation, Bilbao, Bizkaia 3 . University of the Basque Country EHU/UPV, Leioa, Bizkaia 4 . Institute of Experimental Medicine, Budapest, Hungary 5 . Institute for Biochemistry, Leipzig University, Germany 6 . Salk Institute, La Jolla, CA, USA

During adult hippocampal neurogenesis, the majority of the newborn cells undergo apoptosis. To avoid disturbing the surrounding neurons, these apoptotic cells are quickly and efficiently removed by phagocytosis by resident microglia. Here we propose that phagocytosis is not merely a passive process of corpse removal but has an active role in maintaining the homeostasis of the adult hippocampal neurogenic cascade by producing neurogenic regulators. First we performed a genome wide transcriptomic analysis using gene expression arrays to compare cultured naïve vs. phagocytic microglia. Gene ontology analysis revealed that, in addition to major changes in different metabolic and signaling pathways, phagocytosis triggered a pro-neurogenic program in microglia. We found a significant upregulation of the neurogenesis function and identified significant changes in 224 genes involved in functions related to different stages of the neurogenic cascade, including trophic factors (VEGF, FGF2), matrix metalloproteases (MMP3), neuropeptides (VGF, Cartpt), and surface ligands (Jag1). Furthermore, conditioned media from phagocytic microglia altered the proliferation and differentiation of cultured neural progenitors. Finally, we reasoned that phagocytosis impairment would in turn affect neurogenesis and utilized three different transgenic mouse models to block phagocytosis by knock-out of phagocytosis receptors (P2Y12, GPR34, MerTK/Axl). In vivo phagocytosis blockade was accompanied by a downregulation of the neurogenic cascade at different levels, from the proliferation of neuroprogenitors to the number of newborn neurons. Altogether, our data supports that upon engulfment of apoptotic newborn cells, microglia initiates a transcriptional program devoted to support the long term maintenance of the adult hippocampal neurogenic cascade.


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STRIATAL CELL-POSITIONING IMPAIRMENT LEADS TO IMPORTANT AXONAL DEFECTS IN RHOEGT/GT EMBRYONIC BRAINS P. Marfull1, J. Mateus1, A. Meler1, I. Pérez-Roger2, J. Egea1. 1. University of Lleida, Lleida, Spain 2. Universidad CEU Cardenal Herrera, Valencia, Spain

The correct localization of neurons in the developing brain is a key step in the axon guidance process. For instance, migration of the corridor cells is an early step needed for thalamocortical axons (TCAs) to cross the subpallium. Axon-axon interactions are also essential and TCAs interact with corticofugal axons to reach the cortex in the so-called “hand-shake hypothesis”. These processes are coordinated by external signals that often activate RhoGTPases and affect cytoskeleton dynamics. RhoE is a RhoGTPase involved in axon growth and neuron migration. RhoE knock-out mice display neurodevelopmental impairments, such as lack of the common peroneal nerve and reduction of calbindin-expressing neurons in the olfactory bulb. During development, immunofluorescence and axon tracing analysis revealed that RhoEgt/gt mice showed severe axonal projection defects: TCAs were unable to cross the diencephalontelencephalon boundary (DTB) and striatonigral axons (SNAs) were misguided ventrally. Surprisingly, the corridor was not severely affected. Deeper analysis of subpallium revealed that ventral striatum Islet1/RhoE+ cells were misspositioned ventrally, together with Globus Pallidus and striatal axons. We confirmed a similar but less severe phenotype in conditional nervous system (NestinCre-RhoElx/gt) and striatal-LGE (Dlx5/6Cre-RhoElx/gt) knock-out brains. We propose that RhoE is important for the proper migration of Islet1+ neurons in the striatum. In RhoE absence, these neurons are misslocalized affecting SNA projections, which in turn affects secondarily the projection of TCAs through the ventral subpallium. We are currently working on the hypothesis that SEMA3C, expressed by the Pax6+ cells of the lateral migratory stream, exerts a repulsive effect on Islet1+ cells. In summary, our results suggest I) an important function of RhoE in the correct development of brain; II) the correct positioning of ventral striatum cells is needed for a correct SNAs guidance and III) a scaffolding role of SNAs to help TCAs crossing the DTB.


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ALTERATION OF CORTICAL LAYERING PATTERN DURING EARLY DEVELOPMENT CONTROLLING REELIN EXPRESSION Fortes-Marco, Ll.1, Albert-Maestro, M.A.1, Sanz-Piña, E.1, Chico-Garcia, B.1, Soriano, E.2, De Carlos, J.A. 1 1 . Instituto Cajal (CSIC), Madrid, Spain. 2 . University of Barcelona, Barcelona, Spain.

Neuronal cells generated during neocortical development migrate from proliferative zones to their final positions, where they integrate forming cortical circuits. Studies describing this process bring to a spatio-temporal and stereotipated cortical pattern of generation of the whole variety of cortical cells. The dorsal division of the telencephalon (pallium) produces the whole of cortical excitatory neurons. These are projecting cells with almost exclusive pyramidal morphology. On the other hand, the ganglionic eminences, on the ventral division of the telencephalon (subpallium), generate the inhibitory and non-projecting cortical neurons, that migrate tangentially to the neocortex. To correctly integrate all this cell heterogeneity, the proliferative timing and migration pathway are highly tuned. The structuring in 6 horizontal layers of the cerebral cortex is achieved from a sequential pattern generation inside-out, where the cells that are generated before will form the deep layers and the last ones to be generated, the upper layers. Has been described that this is achieved thanks to the reelin, a protein secreted by Cajal-Retzius cells located in the neocortical preplate. Reelin is an extracellular matrix glycoprotein that acts as an attractive tropism factor for the different cell populations that are being generated. Consequently, Reeler -/- mutant mice show absence of reelin and an inverted cortical layer distribution (outside-in). However, other authors suggest that reelin is not the responsible of the sequential pattern of cortical layers. Our aim is to clarify the role of reelin during the early cortical development. Using an inducible Ubi-Cre/FLR Reelin mice, we inhibit the reelin production. Applying this experimental protocol together with electroporation of plasmidic fluorescent reporters, as well as using specific layer markers, we compare the cortical formation and patterning of layer establishment in presence or absence of reelin. Our preliminary results showed a significant disorganization of the cortical layer pattern. Topic: Developmental Neurobiology, Systems Neuroscience


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UNRELATED CELL CYCLE FUNCTION OF CYCLIN D1 CONTROLLING ADHESION IN TBR2+ CELLS RADIAL MIGRATION Daniel Rocandio1, Neus Pedraza1, Ariadna Ortiz1, Eloi Garí1 and Joaquim Egea1. 1 Facultad de Medicina, Universidad de Lleida, Lleida

The best known function of CyclinD1 within the cell is the integration of extracellular signals to cell division. Recent studies show that CyclinD1 may be located as well in the cytoplasm of the cells where it has been proposed to regulate cell adhesion of some cellular lines like macrophages or keratinocytes. Nervous system development is characterized by different aspects (migration, polarization, differentiation, etc...) that require a thigh regulation of cell adhesion. In this context, we wanted to address the role of the cytoplasmic CyclinD1 in vivo. First, we observed that CyclinD1 is expressed, as expected, in the nucleus of the progenitor cells in the proliferative ventricular zone of the telencephalon. Interestingly, we did observe a specific cytoplasmic localization of CyclinD1 within the cytoplasm of the radial glial process of radial glial cells in a spatiotemporal pattern paralleling the initiation of neurogenesis and radial glial directed neuronal migration, which is known to commence and progress in a rostrolateral to caudomedial gradient. This cytoplasmic localization suggests a possible role of CyclinD1 unrelated to cell proliferation, like previous results in the regulation of keratinocyte adherence during differentiation have suggested. To test this idea, we have used in utero electroporation method administering a plasmid with a CyclinD1K112 mutation, which is unable to form the CDK4/6-CycD1 complex. The analysis of electroporated cells suggest an adhesion role in the translocation phase of radial migration of the cortex development, and an advanced migration of electroporated Tbr2 positive cells. In addition, the analysis of CyclinD1 deficient mice reveals an abnormal localization of Tbr2 positive cells in upper layers of the subventricular zone in E16.5 and E18.5 mutant embryos. This phenotype could suggest an important adhesion role of CyclinD1 in the radial migration of postmitotic subventricular cells through the adhesion regulation between basement membrane. Topic: Developmental Neurobiology


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THE HIPPOCAMPAL NICHE TURNS NEURO/ASTROGENIC IN MATURE MICE

S. Beccari1,2,, J. Valero1,3, , M. Maletic-Savatic4, A. Sierra1,2,3 1 . Achucarro Basque Center for Neuroscience, Leioa, Bizkaia, Spain 2 . University of the Basque Country EHU/UPV, Leioa, Bizkaia, Spain 3 . Ikerbasque Basque Foundation for Science, Bilbao, Bizkaia, Spain 4 . Jan and Dan Duncan Neurological Research Institute at Texas Children’s Hospital, Baylor College of Medicine, Houston, TX, USA

Adult hippocampal neuroprogenitors give rise to both neurons and astrocytes. As neuroprogenitors are lost with increased age, neurogenesis concomitantly decreases. However, the dynamics of neuron and astrocyte generation throughout adulthood has not been systematically examined. Here, we analyzed the hippocampal niche both longitudinally (from 2 hours to 30 days of cell life) and transversally (from 1 to 12 months of mouse age) and generated a Marsaglia polar random simulation model of newborn cell dynamics. The sharp decrease in newborn neuron production throughout adulthood was largely predicted by the number of proliferating neuroprogenitors at each age. In contrast, newborn astrocyte decay was slower and associated with an increased yield in mature mice. As a result, the niche switched from neurogenic to neuro/astrogenic with increased age. Our data provides a simple “end-point” model to understand the hippocampal niche changes across adulthood and suggest yet unexplored functions of newborn astrocytes within the aging hippocampal circuitry. This work has been supported by the Spanish Ministry of Economy and Competitiveness with FEDER funds to A.S. (BFU2015-66689-R and RYC-2013-12817) and Ikerbasque startup funds to J.V. Topic: 1. Developmental Neurobiology


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ADULT NEUROGENESIS BEYOND THE CLASSIC NICHES? CHARACTERIZATION OF THE SUBPIAL ZONE OF THE BRAIN

MC. González-Calixto, JM. García-Verdugo, V. Herranz-Pérez Instituto Cavanilles de Biodiversidad y Biología Evolutiva, Universitat de València – CIBERNED, Valencia

Adult neurogenesis is the process of generating new neurons from stem cells during adulthood. In mammals, two main neurogenic niches have been identified: the ventricular-subventricular zone and the subgranular zone of the dentate gyrus. Besides these two niches, the neurogenic capacity in other brain areas, such as subpial zone, a thin strip located under the pia mater, is debated. This region contains cells that proliferate and, to some researchers, could be responsible for a very restricted neurogenesis, as well as for some tumors in the human cerebral cortex. In this study we performed a morphological and molecular characterization of the cell types located in this region in the mouse and human brain. Moreover, we have studied the proliferative capacity of the subpial zone by autoradiographic techniques, electron microscopy and immunofluorescence. Our main finding was the existence of a cell population whose characteristics did not correspond to those of mature neural cell types, but rather to undifferentiated cells. Two months upon labeling, these cells were found at deeper regions of the cerebral cortex and presented characteristics of oligodendrocytes. Under the light of such observation, we believe that further cellular and molecular research into this brain region is necessary in order to ascertain the origin, fate and function of these cells.


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CELL CYCLE RE-ENTRY FOLLOWED BY HYPERPLOIDY TRIGGERS SYNAPTIC DYSFUNCTION IN DIFFERENTIATED CORTICAL NEURONS: AN ALZHEIMER’S DISEASE MECHANISM? E. Barrio-Alonso1, A. Hernández-Vivanco1, C. C. Walton 1, G. Perea1, J.M. Frade1 1 . Cajal Institute, CSIC, Madrid, Spain

Cell cycle re-entry, followed by hyperploidization of differentiated neurons, and synaptic failure are two known events taking place at the earliest stages of Alzheimer’s disease, but their functional connection remains unexplored. To address this question, we used differentiated cortical neurons that were forced to reactivate the cell cycle by SV40 large T antigen (TAg) expression, evidenced by BrdU incorporation and an increase of DNA content. We show that cell cycle re-entry specifically leads to reduced spontaneous electrical activity and diminished spike generation in cortical neurons. This is followed by delayed non-apoptotic cell death independent on oxidative stress. We also show that membrane depolarization by KCl partially rescues TAg-dependent neuronal death even though electrical capacity of TAg-transfected neurons remains reduced, thus suggesting that the survival of AD-associated hyperploid neurons may depend on their insertion in active neuronal circuits. Our results indicate that cell cycle reentry in neurons may actively participate in the AD etiology.


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CB1 RECEPTOR SIGNALING IN EMBRYONIC STEM CELL DIFFERENTIATION INTO CORTICAL NEURONS

J. Paraíso-Luna1-2, D. García-Rincón1-2, J. Aguareles1-2, A. de Salas-Quiroga1-2, J. Díaz-Alonso3, E. GarcíaTaboada1-2, M. Guzmán1-2, I. Liste4, I. Galve-Roperh1-2 1. Centro Investigación Biomédica en Red Enfermedades Neurodegenerativas (CIBERNED), Spain 2. School of Biology, Complutense University of Madrid, Institute Ramón y Cajal for Health Research (IRYCIS) and Institute of Neurochemistry (IUIN), Madrid, Spain 3. University of California, San Francisco, California 94158, USA. 4. Unidad Funcional de Investigación de Enfermedades Crónicas (UFIEC), Instituto de Salud Carlos III, Madrid, Spain.

Pluripotent embryonic stem (ES) cell cultures constitute a powerful tool to investigate key aspects of nervous system development and the regulatory signaling mechanisms involved in neuronal generation and differentiation. The endocannabinoid system exerts a regulatory role of neurodevelopment that influences neural progenitor proliferation, identity and neuronal differentiation. In particular, CB1 receptor signaling controls the differentiation of corticofugal deep layer neurons owing to its ability to regulate the transcription factor switch Ctip2/Satb2. We have developed an ES default neuronal differentiation paradigm aimed to the generation of cortical projection neurons. ES neuronal differentiation generates mainly excitatory glutamatergic neurons (Glu, vGlut1,… ) that express distinctive markers characteristic of upper and deep layer cortical neurons (Tbr1, Ctip2, Satb2, ..). In addition, ES generated glial cells are although at a lesser extent. Proliferating murine ES cells and their differentiated neuronal progeny express CB1 receptors and therefore constitute a robust tool to investigate the role of CB1 signaling in the transition of pluripotent ES to multipotent neural stem cells, and secondly in their neuronal differentiation program. Pharmacological regulation of CB1 receptor signaling during ES-neuronal differentiation reveals a pro-neurogenic action, with increased expression of deep-layer, and reduced upper-layer, cortical neuronal projection markers. Ongoing characterization of the neuronal differentiation changes upon CB1 receptor knockdown in ES cells will be shown. In summary, these findings support that CB1 receptor signaling exerts a cell-autonomous action in ES-derived neuronal differentiation favouring deep-layer specification. In addition, we have developed a protocol allowing the efficient and indefinite source of cortical neurons that constitutes an invaluable methodology to investigate the neuroprotective efficacy of new pharmacological drugs for the management of neurodegenerative disorders. This study was supported by the Instituto de Salud Carlos III (Plan Estatal de I+D+i 20132016), Grant PI15-00310, and cofinanced by the European Development Regional Fund ‘‘A way to achieve Europe’’ (ERDF). Key words: embryonic stem cells; cortical neurons; neural stem cells; endocannabinoid system; neuroprotection. Selected Topic: Developmental Neurobiology


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THE ACETYLTRANSFERASE CBP IS DISPENSABLE FOR PROLIFERATION OF NEURAL PROGENITORS BUT ESSENTIAL FOR NEURAL DIFFERENTIATION R. González Martínez1, B. del Blanco Pablos1, A. Barco Guerrero1, E. Herrera González de Molina1 1 . Instituto de Neurociencias de Alicante. CSIC-UMH, San’t Joan d’Alacant, Alicante, Spain.

Rubinstein-Taybi syndrome (RSTS) is a genetic neurodevelopmental disorder characterized by mental impairment of variable severity and a wide spectrum of congenital abnormalities, that is caused by hemizygous mutations in the genes encoding the KAT3 family of transcriptional coactivator CREB binding protein (CBP) and the E1A binding protein P300 (p300). Both factors have intrinsic lysine acetyltransferase (KAT) activity and are critically involved in the transcriptional and epigenetic regulation of gene expression. Consistent with this central role, CBP and p300 knockout (KO) mice exhibit early embryonic death and neuronal tube closure defects. However, the precise function of these proteins during the development of the central nervous system has not been clearly stated. Here we assess whether KAT3 proteins are necessary for cell proliferation and neuronal differentiation, since this would explain some of the neurological alterations associated with RSTS. Conditional removal of CBP specifically from retinal progenitors (using the Rx-Cre line) or from recently differentiated retinal neurons (using the Brn3b-Cre line) demonstrate that the loss of CBP in differentiated neurons does not affect neuronal viability nor identity, while its deletion in progenitors have a negative impact in the number of retinal neurons. In turn, experiments on neurospheres lacking CBP demonstrate that cell proliferation is normal in the absence of CBP, but both glial and neuronal differentiation are seriously compromised. Together our results indicate that the abnormalities observed in RSTS patients are primarily caused by CBP malfunction during neuronal differentiation. Ongoing experiments designed to remove either p300 alone or in combination with CBP, both in vitro and in vivo, should further clarify the role of KAT3 proteins in neural differentiation and reveal the redundancy between the two paralog transcriptional coactivators.


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CLASS IIA HISTONE DEACETYLASES LINK cAMP SIGNALING TO THE MYELIN TRANSCRIPTIONAL PROGRAM OF SCHWANN CELLS Sergio Velasco1,2, Clara Gomis-Coloma1,2, Jose A. Gomez-Sanchez1,2, Angeles Casillas1,2 and Hugo Cabedo1,2. 1 . Instituto de Neurociencias UMH-CSIC, San Juan de Alicante 2 . Instituto de Investigación Sanitaria y Biomédica de Alicante (ISABIAL-FISABIO), Alicante

Schwann cells respond to cAMP halting proliferation and expressing myelin proteins. We show here that cAMP-signalling induce the nuclear shuttling of the class IIa Histone Daectylase 4 (HDAC4) in these cells. There, HDAC4 binds to the promoter and blocks the expression of c-Jun, a negative regulator of myelination. Strikingly HDAC4 does not interfere with the transcription factor Mef2. Instead, by interacting with NCoR1/SMRT, HDAC4 recruits a class I HDAC that deacetylates histone 3 in the promoter of c-Jun blocking gene expression. Importantly this is enough to induce Krox20 and start differentiation program and myelin gene expression. Using conditional knock out mice, we also show that class IIa HDACs redundantly contribute to activate the myelin transcriptional program and the development of myelin sheath in vivo and are rate-limiting for c-Jun induction after nerve injury, pivotal for the reprogramming of Schwann cells into the repair cell phenotype. We propose that the nuclear-cytoplasmic shuttling of class IIa HADCs in response to intracellular cAMP controls Schwann cell phenotypic transitions and the establishment of the myelin gene expression program. Developmental Neurobiology


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DEVELOPMENT OF PALLIAL ORGANIZATION IN XENOPUS LAEVIS

N. Vidal, S. Jimenez, N. Alfageme, D. Lozano, C. Muñoz-Sánchez, R. Morona, J.M. López, A. González and Moreno N. Facultad Biológicas, Universidad Complutense, 28040 Madrid, Spain.

The pallium of all vertebrates constitutes the dorsal telencephalic division and is a sophisticated and elaborate structure that shows great evolutionary differences. Most data about the pallial organization have been obtained in mammals, but over recent years the evolutionary interest has opened the field to non-mammalian vertebrates. Despite the differences, four comparable pallial regions are recognized in all tetrapod vertebrates. In addition, in the amniote palliun cortical hem and anti-hem regions have been described as secondary organizer centers during development. The present study, following the main developing pallial events described in amniotes, focused on the development of the pallium in the amphibian Xenopus laevis, a representative of the only group of anamniote tetrapods, which has special significance in the transition from water to land. Our aim was to describe a set of important markers of the pallial territories in other vertebrates to recognize subdivisions and pallial boundaries, mainly based on distinct patterns of gene expression. Thus, in Xenopus we found Wnt3a expression in a region comparable to the hem of amniotes, adjacent to the medial pallium, discernible for Lhx2 expression. A possible anti-hem organizer was previously suggested in anurans in the region described as ventral pallium based on its Lhx9 and Tbr1 expressions and the lack of Emx1; although typical anti-hem markers such as Jagg1, Dbx1 and Sfpr1 are not expressed in this particular location. However, this region appears to be the source of numerous cells that express reelin, as in mammals. Markers of the mammalian neocortical layers, also found in the pallium of other amniotes, such as Mef2C, FoxP1, ER81 and Fezf2 have been detected and analyzed in the pallium of Xenopus. Supported by grant BFU2015-66041-P Developmental Neurobiology


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LOSS OF CBP INTERFERES WITH SRF-DEPENDENT NEURONAL GROWTH AND SYNAPTIC MATURATION

1 B. del Blanco1, D. Guiretti1, R. Tomasoni1,2, M. Lipinski1 , M. Scandaglia1, R. Olivares1, Y. Coca1 E. 1 1 Herrera , A. Barco . 1 Instituto de Neurociencias (UMH-CSIC), Molecular Neurobiology, San Juan de Alicante, Spain, 2 IRCCS Humanitas Clinical and Research Center, Manzoni, Milan, Italy.

Dendrites and dendritic spines play key roles in the connectivity of the brain and have been recognized as the locus of long-term synaptic plasticity related to learning and memory. Furthermore, alterations in dendrite branching and morphology are present in many neurodevelomental disorders, which underscores the importance of understanding the transcriptional and epigenetic mechanisms that regulate neuronal outgrowth. The CREB binding protein (CBP) is a large protein with intrinsic lysine acetyltransferase (KAT) activity that functions as transcriptional co-activator for numerous transcription factors. CBP is essential for the development of the nervous system and its hemi- deficiency causes severe intellectual disability in humans and cognitive impairments in mice (1). To determine the specific role of CBP in neuronal differentiation and maturation, we investigated here the consequences of selectively eliminating CBP in recently born neurons through the characterization of nestin-cre::Crebbpf/f and nestin- creERT2::Crebbpf/f mice. Nestin-cre::Crebbpf/f pups suffer perinatal death as a consequence of diaphragm innervation defects. In accordance with these results, ex vivo and in vivo morphological analyzes demonstrate that the absence of CBP in hippocampal neurons, both during embryonic development and in the adult brain, interfered with dendrite outgrowth, spine morphology and chemically induced long- term potentiation (LTP). Furthermore, RNA-seq and Chip-seq data linked the phenotype of CBP-KO neurons with impaired CBP binding and defective activation of transcriptional programs involved in dendritogenesis, synaptogenesis and synaptic activity. In particular, genes downstream of SRF, which is a known transcriptional regulator of dendritic growth and a molecular partner of CBP (2), were among the main targets affected by the loss of CBP in neurons. Some key examples of these important activity-regulated genes affected are Bdnf, Npas4, Fos and Nptx2. To specifically examine the contribution of impaired formation of CBP-SRF complexes to the growth and transcriptional defects observed in CBP-KO neurons, we next assessed the effect of the viral transduction of a constitutively active SRF protein. Notably, SRF-VP16 ameliorated the defects, indicating that CBP loss in newborn neurons specifically interferes with SRF-dependent transcription, dendritic growth and synaptic maturation. 1.- Lopez-Atalaya JP, et al. CBP is required for environmental enrichment-induced neurogenesis and cognitive enhancement. EMBO J. 2011 Aug 16;30(20):4287-98 2.- Scandaglia M, et al. Fine-tuned SRF activity controls asymmetrical neuronal outgrowth: implications for cortical migration, neural tissue lamination and circuit assembly. Sci Rep. 2015 Dec 7;5:17470


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PHOSPHO-BRD4 DEPENDENT CONTROL OF GLI1 EXPRESSION DURING CEREBELLAR GRANULE CELL PROGENITOR CELL CYCLE EXIT C Penas1,2, M.E. Maloof2, J. Rodriguez-Blanco3, Jun Long3, D. Robbins3, and N.G. Ayad2. 1 Institut de Neurociències, Departament de Biologia Cel.lular, Fisiologia i Immunologia, Universitat Autònoma de Barcelona, Bellaterra, Spain, 08913 2 Center for Therapeutic Innovation, Department of Psychiatry and Behavioral Sciences, University of Miami, LPLC, , Miami, FL, 33136 3 Department of Surgery and Biochemistry and Molecular Biology, Molecular Oncology Program, University of Miami Miller School of Medicine, Miami, FL, 33136

Background: The bromodomain-containing protein 4 (BRD4) belongs to the bromodomain and extraterminal domain (BET) proteins epigenetic readers. BET proteins modulate gene expression by binding to acetylated lysine residues on chromatin-associated proteins and recruit transcriptional complexes. However, although there is an increasing interest on the biological significance of BRD4, the complete mechanisms controlling its activity and its target specificity are not completely understood. For understanding these processes, we used granule cell progenitors (GCPs) and studied the contribution of BRD4 to their development. GCPs produce granule neurons, which are the most abundant neuron in the mammalian brain. Materials and methods: We cultured cerebellar postnatal GCPs and analysed the RNA and protein levels progress during cell cycle exit. We used chromatin immunoprecipitation studies, to analyze the binding of BRD4 to GLI1 locus. The transcription factor GLI1 is major effector of the Sonic Hedgehog mitogenic pathway. We used casein kinase 1 delta (CK1D) transgenic animals, in vitro phosphorylation studies and chromatin immunoprecipitation studies to underscore the effect of CK1D on BRD4 activity. Results: We describe a novel mechanism by which BRD4 is recruited to the chromatin to perform genetic transcriptional activation. We show that BRD4 is phosphorylated by CK1D, driving the expression of the transcription factor GLI1 in GCPs. During cell cycle exit, as CK1D levels drop, BRD4 phosphorylation decays as does binding to the chromatin. Inhibition or conditional deletion of CK1D also reduces BRD4 phosphorylation and binding to the GLI1 locus in neuronal cells. Conclusions: BRD4 phosphorylation by CK1D represents a novel signaling pathway, which can contribute to add another layer of complexity to the functional regulation of epigenetic reader enzymes. Topic: Developmental Neurobiology


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A MORPHOLOGICAL AND GENOARCHITECTONIC MODEL OF THE MOUSE PALLIAL AMYGDALA BASED ON RADIAL ORGANIZATION.

E. Garcia-Calero 1, M. Martinez-de-la-Torre 1, L. Puelles 1, 1 . Faculty of Medicine, University of Murcia and Murcia Institute of Biomedical Research (IMIB-Arrixaca, 30120, El Palmar, Murcia), Spain.

The pallial amygdala is a heterogeneous group of nuclei in the temporal pole of the mammalian telencephalon. This structure is implicated in emotional learning, memory and social communication. Amygdalar dysfunction is described in human diseases like autism spectrum disorders, epilepsy, and anxiety disorders. Studies of amygdalar structure follow tradition in identifying various nuclei or corticoid formations on the basis of their topography in conventional coronal sections; these elements are grouped into functional regions according to connectivity (Swanson and Petrovich, 1998). There is little reference to the pattern of local histogenesis, which is widely assumed to represent mostly radially migrated populations, but we lack definitive ascription of each population to specific progenitor domains and histogenetic strata. It is still controversial whether the pallial amygdalar nuclei variously originate from all the pallial sectors (ventral, lateral, dorsal and medial), or just from a subset of them (Puelles et al., 2000, 2016; Medina et al., 2004; Puelles, 2014). In the present work, we focused on the radial developmental pattern of the mouse pallial amygdala. To this end, the expression of region-characteristic molecular markers was analysed from early embryonic stages (E12.5) to postnatal phases (P4) in an optimal section plane based on amygdalar radial glia The results suggest a new model of amygdalar nuclear complexes organized in distinct radial morphological units (Nieuwenhuys and Puelles, 2016). This model may be useful to understand neurogenetic patterns, explain tangential migrations, and assess the topology of both afferent inputs and efferent cell populations. BFU2014-57516P; SENECA 19904/GERM/15.


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TANGENTIAL MIGRATORY ORIGIN OF THE MOUSE VENTRAL PREMAMILLARY NUCLEUS IN THE HYPOTHALAMIC RETROMAMILLARY AREA.

López-González L1., and Puelles, L1. 1 Faculty of Medicine, University of Murcia and Murcia Institute of Biomedical Research (IMIB-Arrixaca, 30120, El Palmar, Murcia), Spain.

The ventral premamillary nucleus (VPM) is a compact ovoid mass of glutamatergic neurons placed bilaterally within the mammalian (basal) ventral tuberal (TuV) area of the terminal hypothalamus (THy), just under the ventromedial hypothalamic nucleus. It is connected periventricularly via a corridor of similar neurons with the retromamillary area (RM), found in the peduncular hypothalamus (PHy); this corridor perforates the distinct perimamillary (PM) band that separates RM from VPM. Puelles et al. (2012), from where all these terms are extracted, suggested that this arrangement possibly reveals a tangential migration. In order to explore this issue, we first used in situ hybridization and immunohistochemistry to show that the mouse VPM primordium and RM area, as well as the interconnecting corridor, selectively share various molecular markers (e.g., Foxa1, Nr4a2, Irx5, Satb1) and appear continuous at critical developmental timepoints. This supports in principle that the RM area may represent the progenitor area where the VPM neurons are generated. This also implies their migration from PHy into THy. To demonstrate experimentally the deduced tangential migration, we prepared organotypic explant cultures including the whole E13.5 mouse hypothalamus and diencephalon, and labeled therein the RM area with DiI. Our results after 2-3 days in vitro illustrate DiI labelling of a cellular corridor of neurons traslocating selectively from the RM area into the TuV area. These data are consistent with a retromamillary origin and subsequent tangential migration of at least the main population of the VPM nucleus. Supported by grants BFU2014-57516P and 19904/GERM/15 to L.P.


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REGULATION OF CEREBRAL CORTEX DEVELOPMENT BY miR3607

K. Chinnappa, C. de Juan Romero, U. Tomasello and V. Borrell Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas & Universidad Miguel Hernández, Sant Joan d’Alacant 03550, Spain

The presence of an extensive OSVZ in the developing primate cerebral cortex is thought to be highly responsible for gyrification. This germinal layer houses a special type of progenitor cell, called basal Radial Glia Cell (bRGC) with high amplification potential and directly related to the process of folding. Regional differences in OSVZ across the cerebral cortex of primates and ferret have been reported, in which areas with greater OSVZ proliferation give rise to folds and areas with lower OSVZ proliferation give rise to fissures. The molecular mechanisms regulating this regional difference in germinal zones are unknown. In order to study these mechanisms, a microarray analysis was carried out in our lab to identify genes differentially expressed in the germinal layers of prospective gyrus and sulcus. Transcriptome analysis revealed some miRNAs showing significant difference in expression between these regions, along with the differential expression of several of their target genes. Based on this analysis and in silico predictions, we hypothesize that miR3607 might act as an important regulator of expansion and gyrification of the cerebral cortex. Experiments of gain of function for miR3607 in mouse embryos indicates its involvement in the regulation of progenitor cell lineage and premature migration of cells to the cortical plate. Overexpression of miR3607 altered distribution of cells across the cortex compared to miRscrambled control with a loss of cells from germinal layers and an increase in neuronal layers. These differences were accompanied by changes in the proportion of Pax6 and Tbr2 positive cells. These findings suggest that miR3607 levels regulate the balance between progenitor cell self-renewal and neurogenesis. Ongoing work is aimed at investigating the role of miR3607 in gyrification of the cerebral cortex using ferret as a model system.


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FULL MICROGLIAL ACTIVATION AFTER IFN-GAMMA/LPS-MEDIATED PRIMING LEADS TO INCREASED PHAGOCYTOSIS OF DOPAMINERGIC CELLS IN AN IN VITRO MODEL OF PARKINSON'S DISEASE Casanova P.V1, Saavedra E1, Barcia C1. 1 Departament of Biochemistry and Molecular Biology, Institut de Neurociències, Universitat Autònoma de Barcelona, Barcelona.

Microglial cells constitute the first barrier of the innate immune response in the brain and continuously scan the surrounding extracellular space and communicate with other cells, including neurons. Changes in microglial phenotype and function are observed during neurodegenerative conditions such as Parkinson’s disease (PD). Our aim is to determine whether microglial cells, when fully activated after priming, are able to increase the phagocytosis of dopaminergic neurons in an in vitro model of PD. We studied the activation that leads to phenotypical changes of BV-2 microglial cell line. Firstly, we analyzed the response of these cells to pro-inflammatory agents such as lipopolysaccharide (LPS) or IFN-gamma, simulating the neuro-inflammatory environment that occurs during PD. The release of nitrites by these cells was studied as an indicator of their activation and immunocytofluorescence essays allowed us to see morphological changes due the aforementioned activation. Pre-activated microglial cells were set up in a co-culture with PC12 dopaminergic cells as an in vitro model of the disease, allowing us to see whether BV-2 cells increase their phagocytic domains over PC12 cells. Results indicate that treatment with IFN-gamma alone provokes a release of low concentrations of nitrites. However, full activation of microglial cells was achieved when challenging the cells with IFN-gamma and then insulting them with LPS, as seen by the elevated nitrite release. Preliminary experiments with primary cultures of microglia demonstrated corresponding results with the BV-2 cell line. Importantly, microglial cells were able to spontaneously phagocytose PC12 cells over the course of one hour. Interestingly, engulfments were significantly elevated when BV-2 cells were fully activated after priming. These results suggest that microglial priming is an important factor in the inflammatory-mediated dopaminergic neurodegeneration and will help us understand the role that the immune response plays in parkinsonism, highlighting the significance of the inflammatory component in PD therapy. Neuronal excitability, synapses and glia: cellular mechanisms


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RELATIVE CONTRIBUTIONS OF MATERNAL HORMONES AND FETAL D2 TO THYROID HORMONE ECONOMY DURING PERINATAL DEVELOPMENT IN MICE

S. Bárez-López1,2, MJ. Obregon1, J. Bernal1,2 and A. Guadaño-Ferraz1,2 1 . Instituto de Investigaciones Biomédicas Alberto Sols, Consejo Superior de Investigaciones Científicas (CSIC)Universidad Autónoma de Madrid (UAM), Madrid, Spain. 2 . Center for Biomedical Research on Rare Diseases (Ciberer), Instituto de Salud Carlos III, Madrid, Spain.

Thyroid hormones (THs, T4 and T3) play an essential role in neurodevelopment. The concentrations of the genomically active hormone T3 in brain depend on TH transport across brain barriers through specific TH transporters, the local generation of T3 from T4 by type-2 deiodinase (D2), and TH degradation by Type-3 deiodinase (D3). In addition, during embryonic development, circulating fetal TH concentrations derive partly from the mother. How all these factors interact to ensure brain euthyroidism in mice is not well known. This work has explored the sources of brain T3 during mice fetal development by measuring TH levels in plasma and TH content in tissues by radioimmunoassay; by studying the expression of the gene encoding for D2 (Dio2) at a histological level in the perinatal mouse brain by in situ hybridization; and by assessing the expression of T3dependent genes and TH transporters in different mouse models by qPCR. The findings revealed that during late gestation, a large amount of fetal brain T4 is of maternal origin. Also, in the developing mouse brain, fetal T3 content is regulated through the conversion of T4 into T3 by D2 activity, which is present from earlier prenatal stages. Additionally, D2 activity was found to be essential to mediate expression of T3-dependent genes in the cerebral cortex. Notably, Dio2 was mainly expressed at the blood-cerebrospinal fluid barrier (BCSFB). Overall, these data signify that T4 deiodinated by D2 may be the only source of T3 during brain development. We therefore propose that D2 activity at the BCSFB converts the T4 transported across the choroid plexus into T3, thus supplying the brain with active hormone to maintain TH homeostasis. Developmental Neurobiology


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SOXD GENES IN THE CONTROL OF ADULT NEUROGENESIS

Lingling Li1, Elena Calleja1, M. Mar Muñiz1, Alejandra C. Quiroga1, Marco A. Cañizares1, Silvia Nicolis3 Véronique Lefebvre2 and Aixa V. Morales1 1 Instituto Cajal, (C.S.I.C), Madrid, Spain. 2 Cleveland Clinic Lerner Research Institute, Cleveland, Ohio, USA 3 University of Milano-Bicocca, Milano, Italy.

During the development of the nervous system, the generation of hundreds of subtypes of neurons and glial cells relies upon the relatively fast production, amplification, specification and differentiation of a pool of neural progenitors and neural stem cells (NSCs). Surprisingly, this strategy is retained to some extent in niches in the adult nervous system throughout lifetime under physiological conditions. Although the molecular mechanisms involved in both embryonic and adult neurogenesis are conserved, it is not clear how the differences in the cell production rates and in the temporal extent of neurogenesis can be attained. Genes of the Sox family of transcription factors are essential during neurogenesis. In the developing spinal cord, we have determined that Sox5 controls cell cycle exit of neural progenitors and the specification of subtypes of dorsal interneurons, counteracting the Wnt signalling pathway (Martínez-Morales et al., 2010; Quiroga et al., 2015). More recently, we have characterized that both Sox5 and Sox6 are expressed in the majority of NSCs and in early intemediate progenitor cells (IPCs) in one of the longer lasting neurogenic niches, the subgranular zone (SGZ) of the dentate gyrus of the adult mouse hippocampus. Using inducible targeted deletions: Sox5fl+/fl+ and Sox6fl+/fl+ mice crossed to a transgenic Sox2cre-ERT2 line inducible by tamoxifen, we have determined that in the absence of Sox5 and/or Sox6 neurogenesis in the SGZ is reduced, observed by a clear reduction in the number of IPCs (Tbr2 +) and and inmature neurons (Dcx+). This is in part to the fact that Sox5 and Sox6 are required for the the self-renewal ability of the NSCs of the DG. However, changes in the proliferation of the IPCs could also account for the defect in neurogenesis. Together, these results suggest that Sox5 and Sox6 control the activation, proliferation and/or stemness of NSC/IPCs during adult hippocampal neurogenesis.


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STUDY OF PROLIFERATION, NEUROGENIC AND GLIAL MARKERS DURING THE DEVELOPMENT OF THE OLFACTORY BULB IN SHARKS. A. Docampo-Seara1, E. Candal1, MA Rodríguez1 1 . BRAINSHARK group. Faculty of Biology (CIBUS). University of Santiago de Compostela. A Coruña.

Several studies in mammals show that the transcription factors implicated in the development of the telencephalon are similar to those operating in the development of the olfactory bulb (OB). Recently, a high molecular similarity was reported between mammals and cartilaginous fishes regarding development of the telencephalon. However, information about the molecular mechanisms that operate in the development of the OB is lacking in cartilaginous fishes. In contrast with mammals, where proliferating cells reach the OB through the rostral migratory stream, bony fishes rely upon an additional endogenous source of proliferation in the OB during adulthood. However, this fact has not been described in cartilaginous fishes. The aims of the present study are (1) studying the proliferation pattern in the OB of embryos and juveniles of the catshark Scyliorhinus canicula, and (2) studying the development of the OB in this species by analyzing the expression of transcription factors (Pax6, Tbr1, Tbr2, NeuroD) and the distribution of glial markers (BLBP, GFAP, GS). Our results show abundant endogenous proliferating cells in the OB during embryonic development and juveniles. A few of these cells show a glial phenotype, though further characterization studies are necessary to elucidate the neurochemical nature of proliferating cells. In addition, Pax6, Tbr1, Tbr2, and NeuroD are expressed during development of the OB, though they are not sequentially expressed (but rather overlapped), contrary to what happens in mammals. Numerous glial cells are also present encapsulating the glomeruli at the end of the embryonic phase, when the morphology of the OB is achieved, suggesting a possible role for these cells in the achievement of correct synaptogenesis. Present results show that transcription factors implicated in the development of the OB seems to be conserved throughout vertebrate evolution. Supported by Ministerio de Economía y Competitividad-FEDER (BFU2014-5863) Developmental biology


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EMBRYONIC ORIGIN OF THE VASOPRESSIN CONTAINING CELLS OF THE FOREBRAIN B. Castro-Robles , E. Desfilis, L. Medina Facultat de Medicina. Universitat de Lleida, IRBLleida, Lleida, Spain

The nonapeptides vasopressin and oxytocin play key roles in several aspects of social behavior and cognition, such as affiliation, pair-bonding, and materno-filial recognition. In the brain, they are mainly produced by neurons of the paraventricular (PVN) and supraoptic (SO) hypothalamic nuclei, whose axons release them as hormones in the neurohypophysis. Both nonapeptides are also released in the brain from these neurons and other subpopulations of the hypothalamus and the extended amygdala, acting as neurotransmitters/neuromodulators. While vasopressinergic and oxytocinergic neurons of the PVN and SO are supposed to originate in the supraopto-paraventricular hypothalamic domain (SPV) and their differentiation depends on the transcription factor Otp, experimental demonstration is missing. Moreover, the origin of the vasopressinergic and oxytocinergic neurons located outside PVN and SO is unknown. We performed migration assays in mouse embryonic forebrain slices, using a fluorescent cell tracker, followed by immunofluorescence in order to study the origin of vasopressin containing neurons of the hypothalamus and telencephalon. To better understand the location of the migration routes, we compared our results to data on expression of Otp, Islet1, Rgs4, vasopressin, and radial glial disposition. The migration routes differed depending on the cell tracker position. Only when the tracker was placed in the terminal or peduncular SPV, the migration routes mimicked the distribution of Otp cells observed during development. From the terminal SPV, cells migrated dorsally to the preoptic area, and ventrally to the chiasmatic region. From the peduncular SPV, many cells migrated following the radial dimension, reaching the lateral hypothalamus, SO, and a narrow branch of the posterior BSTM. In addition, tangential migration of cells was observed to the lateral BSTM and other parts of the medial extended amygdala, as well as to the ventral hypothalamus. Following immunofluorescence for vasopressin, we observed numerous cases of colocalization between the cell tracker and the nonapeptide. Sponsor: MINECO and FEDER, grant no. BFU2015-68537-R Topic: 1. Developmental Neurobiology


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DEVELOPMENTAL EFFECTS OF POSTNATAL EXPOSURE TO THE PESTICIDE CHLORPYRIFOS AND ITS INTERACTION WITH APOE GENOTYPE P. Basaure García 1, L. Guardia-Escote 2, M. Cabré Bargalló 2, F. Peris-Sampedro 1, MT. Colomina Fosch 1 1 . Facultat de Ciències de l'Educació i Psicologia, Universitat Rovira i Virgili, Tarragona, Spain 2 . Facultat de Medicina i Ciències de la Salut, Universitat Rovira i Virgili, Tarragona, Spain

Chlorpyrifos (CPF) is one of the most commonly used pesticides in the world. Several investigations have confirmed short-term neurotoxic effects after CPF exposure in neonatal period. The three most frequent human apolipoprotein E (apoE) isoforms have been shown to differentially affect neurobiological and metabolic processes. Particularly, interactions among environmental toxic factors and genotype apoE are recognized. The aim of this research was to study the genotype apoE contribution on physical and biochemical changes induced by a postnatal CPF exposure. Transgenic mice apoE3 and apoE4 of both sexes were exposed to CPF on postnatal days (PND) 10-15 at doses of 0 or 1 mg/kg/bw/day. Plasma and forebrain cholinesterase (ChE) activity, physical and neuromotor development were evaluated. Gene expression of detoxification enzymes in liver and cholinergic markers in brain, was characterized. In general, CPF produce a delay in eye opening, affected neuromotor function and inhibited plasma ChE. ApoE3-mice showed increased expression of butyrylcholinesterase and acetylcholinesterase-S, while apoE4-mice had a higher acetylcholinesterase-R expression. CPF-treated apoE3 displayed an increased expression of both PON2 and PON3 in liver, but also a diminished expression of vesicular acetylcholine transporter in brain at both PND 15 and 30. These results point to long-lasting effects of early CPF exposure on cholinergic system and suggest different vulnerabilities according to apoE genotype. This research was supported by the Ministry of Economy and Competitiveness; reference PSI201455785-C2-2-R


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HETEROGENEITY OF GLIAL CELLS BASED ON THE EMBRYONIC SPATIO-TEMPORAL ORIGIN R. Sánchez-González, A. Bribián and L. López-Mascaraque Instituto Cajal-CSIC, Madrid, Spain.

So far, the origin of glia cells still remains unclear, even a large number of studies revealed the heterogeneous nature of adult glial cells. How such glial diversity is established in developing embryo?. Most of our knowledge derives either from in vitro studies, different models, methodologies or embryonic stages, which greatly hinders a convenient comparison. During development specific types of glial cells are generated from independent progenitors (GarcíaMarques and Lopez-Mascaraque, 2013; 2017), although it remains unknown the spatial origin of those progenitors. In particular, astroglial heterogeneity is associated with the multiple developmental origins of these cells. For this purpose we used the multi-color lineage tracing system, the StarTrack method, a powerful tool to study glial diversity and functionality by analyzing their lineages in the mice brain. The particularity of this clonal analysis consists on labeling one single progenitor cell. So, this permits to analyze the lineage of these single cells based on gene transfection of embryos. Through in vivo StarTrack co-electroporations, we transfected and label progenitor cells with various reporter genes, to permanently label the cell and all its descendants. We specifically targeted those SVZ progenitors located within subpallial or pallium territories, to analyze the type and location of adult labelled cells related to their origin and embryonic stage. Star Track labelled cells exhibited different neural phenotypes and were located at different regions that were classified in relation to the targeted embryonic area. Hence, the precise origin of different glial subtypes is crucial to understrand the glial heterogeneity and to increase our basic knowledge of glial cell biology both at embryonic and adult brain. Supported by research Grant BFU2016-75207-R from MINECO 1 Neurobiología del Desarrollo 2 Nuevos métodos y tecnologías


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NRP2 AS A ZIC2 EFFECTOR DURING NEURAL CREST CELLS MIGRATION

A. Giner de Gracia1, G. Muça1, A. Escalante Rodríguez1, C. Morenilla-Palao1 and E. Herrera González de Molina1 1 Instituto de Neurociencias de Alicante (CSIC-UMH), Alicante, Spain.

The Zinc Finger Protein of the Cerebellum 2 (Zic2) encodes a transcription factor that plays an important role in early stages of neural development. Mutations in Zic2 cause holoprosencephaly, spina bifida and many other body malformations. It has been demonstrated that during development, Zic2 is essential for the formation of the neural crest (NC) but its precise role in this process has not been clearly described. The NC is a population of migratory cells with an extraordinary potential to differentiate and contribute to nearly every organ in the adult body. Through functional experiments in vivo we first demonstrate here a critical role for Zic2 in the migration of NC cells without affecting proliferation, cell death or cell fate. Second, in an unbiased genome-wide screen, we identified the transmembrane protein Nrp2 as a potential effector for Zic2. Nrp2 is a receptor for some of the SEMA3 family ligands that has been previously described as a guidance molecule for NC cells. We confirmed that Zic2 and Nrp2 are highly co-expressed in premigratory NC cells and observed that downregulation of Zic2 leads to a significant reduction in the expression of Nrp2. Even further, overexpression of Nrp2 in the developing neural tube produced an accumulation of NC cells at the dorsal mesenchyme that partially recapitulates the Zic2 gain-of-function phenotype. All these findings together indicate that Zic2 controls the expression of Nrp2 and both molecules are essential for the proper formation of the NC.


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ATTENUATION OF ROBO SIGNALING PROMOTES CEREBRAL CORTEX EXPANSION IN EVOLUTION

A. Cárdenas 1, C. de Juan Romero 1, E. Picó 1, A. Villalba 1, A. Tzika2, M. Tessier-Lavigne3, L. Ma4, M. Milinkowitch2, V. Borrell 1 1 Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas & Universidad Miguel Hernández, Sant Joan d’Alacant, Alicante, Spain 2 University of Geneva, Switzerland 3 Rockefeller University, NY, USA 4 Thomas Jefferson University, PA, USA.

The olfactory bulb (OB) develops as a unique specialization of the rostral pallium (OB primordium) from early stages of development. Here we show that the distinction between OB and neocortical (NCx) development starts at the onset of neurogenesis, with changes in progenitor cell cycle parameters such as cycle lengthening and increased cycle exit, producing within a short developmental period a prominent amount of neurons. We find that these changes in progenitor cell dynamics involve mainly apical progenitors, and are linked to an equally important accumulation of newborn pallial neurons within the VZ of the OB primordium, virtually absent in the neocortex. Time-course and time-lapse analyses of progenitor cell lineages demonstrate that these differences between OB and NCx are preceded by significant changes in progenitor cell dynamics, mostly the abundant occurrence of direct neurogenesis from apical Radial Glia Cells (aRGCs). We show that direct neurogenesis is nearly anecdotic in the neocortex, where the majority of neurons are born from intermediate progenitor cells through indirect neurogenesis. We also identify Robo1 and Robo2 receptors as key molecules regulating the balance between direct and indirect neurogenesis. We show that Robos are highly expressed in aRGCs of the OB but not NCx, and in their absence OB neurogenesis and growth are impaired. Finally, we demonstrate that this regulation of direct vs indirect neurogenesis by Robo1/2 requires the cooperation with the Notch signaling pathway, and that this molecular mechanism of regulation is conserved along the evolution. Topic: 1. Developmental Neurobiology


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THE ROLE OF THE SYNAPTIC PROTEIN SV2B IN EMBRYONIC DEVELOPMENT OF THE CEREBRAL CORTEX

A. Villalba 1, J. Wesseling 2, V. Borrell 1 1 . Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas & Universidad Miguel Hernández, Sant Joan d’Alacant, Alicante, Spain 2 . Centro de Investigación Médica Aplicada, Pamplona, Navarra, Spain

The Outer Subventricular Zone (OSVZ) is a unique germinal layer crucial for the evolutionary expansion of the mammalian cerebral cortex, promoting gyrencephaly. By using ferret as animal model of folded brains, we have recently identified a critical period during early embryonic development when apical Radial Glia Cells (aRGCs) in the ventricular zone (VZ) undergo selfconsuming divisions to produce massive amounts of basal Radial Glia Cells (bRGC). These earlyformed bRGCs are the founder progenitor cells of the OSVZ, and blockade of bRGC production during this critical period profoundly impairs the formation of the OSVZ. The gene encoding for Synaptic Vesicle Glycoprotein 2B (Sv2b) is differently expressed in the VZ before, during and after the critical period for OSVZ formation, and hence it is an attractive candidate to regulate this process. Importantly, Sv2b is expressed in the germinal layers of the developing ferret cortex but not in mouse, with a small and smooth cortex without bRGCs nor OSVZ. We have overexpressed Sv2b in progenitor cells of the embryonic mouse cortex by in utero electroporation at E14, and found that in the short-term (E17) it disrupted the distribution of electroporated cells. Sv2b overexpression disassembled the laminar organization of the VZ, induced the delamination of aRGCs to basal positions and altered their proliferation. At mid-term (P5), we observed the formation of a fold-like bulge in the electroporation site, with normal lamination of cortical neurons. We propose that this gene may play important roles in the developmental formation of bRGCs and the OSVZ, and hence in the expansion and folding of the mammalian cortex. Topic: 1. Developmental Neurobiology


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UNRAVELLING COMMON MECHANISMS INVOLVED IN CROSSMODAL PLASTICITY OF SENSORY SYSTEMS

V. Moreno-Juan1 and G. López-Bendito1 1 .Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas (UMH-CSIC), Sant Joan d’Alacant, Spain

Understanding how the brain adapts to the sensory lost might help us to better decipher the role of intrinsic and extrinsic mechanisms involved in cortical development. A paradigm extensively used to unravel the role of the afferent input during the development of the cortex, is the deprivation of one sensory modality. The deprivation of one sensory modality leads to an adaptive reorganization of the deprived and non-deprived sensory circuits. We are interested in understanding the mechanisms that trigger these adaptations using mouse models in which visual or auditory input is removed from embryonic life. Our laboratory has recently shown that when visual input is removed embryonically, the thalamus triggers a profound reorganization of the somatosensory cortex through changes in thalamic gene expression and thalamocortical axonal branching (Moreno-Juan el al., 2017). This cross-modal adaptation that takes place in the thalamus through spontaneous activity patterns that communicate distinct sensory thalamic nuclei. Although these cross-modal adaptations are present after embryonic visual deprivation and depend on changes in thalamic spontaneous activity, we still do not know how general is this mechanism and whether other sensory systems follow the same rules. Here we have developed a new strategy to study the brain adaptations after embryonic auditory input deprivation. We are able to successfully ablate the cochlea bilaterally at E15.5 in mouse to investigate the thalamic and cortical adaptations that are triggered after embryonic auditory injury. We have found that the mechanisms driving cross-modal plasticity in the cortex are common among sensory modalities. Our results will help to better understand how the brain adapts to sensory injury and to investigate possible therapeutic targets promoting behavioural gains and eliminating those connections that may be maladaptive.


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NEURAL STEM CELL QUIESCENCE IS ASSOCIATED WITH LOW PROTEIN SYNTHESIS AND INCREASED WNT SIGNALING INTEGRATION

L García-Corzo 1, L Remacha 2, R Hortiguela 2, C Terrón 3, D Luque 3, V López 2 and H Mira1. 1 Stem Cell and Aging Unit, Institute of Biomedicine of Valencia (IBV), Spanish National Research Council (CSIC), Valencia, Spain. 2 Chronic Diseases Program. Institute of Health Carlos III (ISCIII), Madrid, Spain. 3 Electronic and Confocal Microscopy Unit. Institute of Health Carlos III (ISCIII), Madrid, Spain.

Background: Neurogenesis persists in specific areas of the adult mammalian brain, the so-called neurogenic niches, due to the life-long maintenance of neural stem cell (NSC) reservoirs [1]. NSC quiescence, which is key for the maintenance of neurogenesis in the adult hippocampus, is regulated by several niche factors including bone morphogenetic proteins (BMPs) and WNT signaling pathway [2]. The intrinsic molecular program underlying adult hippocampal NSC quiescence is beginning to unfold. Recent studies reveal that quiescent NSCs have a molecular signature at the mRNA level that points to an active niche signaling integration capacity and a low protein translation profile, but the functional consequences of this mRNA signature remain unknown [3]. Other studies in stem cell systems also show a decrease in protein synthesis in quiescence, pointing to the existence of common mechanisms regulating the quiescent state of adult stem cells [4,5]. Materials and Methods: To elucidate the molecular program that characterizes the adult NSC, we combined a genome-wide analysis of gene expression with the characterization of the overall translational efficiency and polysomal profiles of quiescent and proliferating cells. Additionally, we analyzed several genes and pathways related with the regulation of translation. Finally, we defined the expression of several WNT pathway components and characterized the WNT signaling integration capacity of quiescent vs. proliferating NSCs. Results: The results obtained show that NSC quiescence is characterized by an overall decrease in ribosome content, polysome loading and protein synthesis, but despite the global decrease in translation, WNT pathway genes are efficiently translated and quiescent cells respond better to WNT ligands. Conclusions: This study demonstrates that quiescent NSCs are endowed with low translation rates and are “primed” to respond to WNT signaling. This further suggests that quiescent NSCs are sensitized for rapidly reacting to the neurogenic demands of the brain. Supported by grants from National Programme for Research Aimed at the Challenges of Society from Ministry of Economy and Competitiveness (MINECO) to H.M. (SAF2015-70433-R) and postdoctoral programme “Juan de la Cierva” (MINECO) to L.G-C.

References: 1. Reynolds BA et al. Science (1992). 2. Mira H et al. Cell Stem Cell (2010). 3. Shin J et al. Cell Stem Cell (2015). 4. Zismanov V et al. Cell Stem Cell (2016). 5. Blanco S et al. Nature (2016).


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IDENTIFYING NEW GENOMIC MECHANISMS CONTROLLING AXON GUIDANCE DECISIONS M. Fernández-Nogales 1, Fernàndez-Albert, J 1, R. González-Martinez 1, A. Barco 1, E. Herrera 1 1 Instituto de Neurociencias de Alicante (CSIC-UMH), Alicante, Spain.

Binocular vision relays on the existence of contralateral Retinal Ganglion Cells (cRGCs) that transmit visual information from each eye to the opposite side of the brain and ipsilateral ganglion cells (iRGCs) that carry sensory information from each retina to the same brain hemisphere. The decision of crossing or avoiding the midline that visual axons take at the optic chiasm during embryonic development is a binary, and consequently, simple axonal choice that represents an ideal model to search for new mechanisms controlling axon guidance responses during the formation of neural circuits. Numerous membrane proteins involved in axonal pathfinding have been identified and characterized in the last few decades, but the mechanisms that regulate the expression of specific transcription factors controlling axon guidance decisions are poorly understood. In an attempt to identify new regulatory mechanisms determining axon guidance decisions, we have compared the chromatin status of iRGCs and cRGCs using Cre-transgenic lines specific for these two retinal populations (Slc6a4-Cre for iRGCs, Pou4f2-Cre for cRGCs) combined with a third transgenic line (SUN1-reporter line) to selectively label their nuclear membrane. We have differentially isolated nuclei from these two populations of RGCs from mouse embryos at the moment that visual axons are deciding whether or not to cross the midline and performed ATACseq (Assay for Transposase Accessible -chromatin) and RNAseq. This approach should allow us to identify differences in transcription, chromatin accessibility and transcription factor occupancy that correlate with midline crossing decisions, potentially revealing new genomic mechanisms regulating this process.


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CPT1C REGULATION OF LATE ENDOSOMES TRANSPORT ALONG THE AXON

Marta Palomo- Guerrero 1, Harald Stenmark2 & Nuria Casals 1 1 Basic Sciences Department, Faculty of Medicine and Health Sciences, International University of Catalonia, Sant Cugat del Vallés, Barcelona, Spain. 2 Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Montbello, Oslo, Norway.

Introduction: Carnitine palmitoyltransferase 1C (CPT1C) is an endoplasmic reticulum protein that has no catalytic activity but maintains the ability to bind malonyl-CoA, an intermediary in the synthesis of fatty acids, whose levels highly fluctuate depending on the energetic status of the cell. Consequently, CPT1C has been proposed to be a sensor of malonyl-CoA in neurons. A CPT1C mutation has been described to cause pure hereditary spastic paraplegia (HSP), a group of neurological disorders characterized by slowly progressive weakness and spasticity of the muscles of the legs, caused by axonopathy of corticospinal motor neurons. Genetic analysis has identified more than 50 different loci involved in HSP, being mutations in Protrudin responsible for a large number of cases. Protrudin has recently been involved in late endosome (LE) transport along the axon and neurite growth. Our main objectives were to demonstrate: 1) the interaction between CPT1C and Protrudin, 2) CPT1C regulation of LE transport depending on malonyl-CoA levels, and 3) CPT1C involvement in axon growth. Material and methods: CPT1C-Protrudin interaction was demonstrated by fluorescence resonance energy transfer (FRET) analysis. Neurite outgrowth measurements were performed in primary culture mouse cortical neurons from WT or CPT1C KO embryos. Analysis of the LE velocity and distance was performed in live Hela cells using a Delta Vision Deconvolution microscope (Applied Precision, GE Healthcare) in collaboration with Oslo University Hospital Research. Results: We demonstrate that CPT1C is necessary for the proper growth of axons in cortical neurons, and regulates LE transport. FYCO1 LEs positive, show a strong movement towards the cell periphery only in CPT1C overexpressing cells and this effect is dependent on malonyl-CoA levels. When CPT1C and Protrudin are overexpresses and malonyl-CoA levels are decreased, LEs are localized in perinuclear area. Moreover, FRET studies demonstrate the interaction between CPT1C and Protrudin. Conclusions: CPT1C- Protrudin system is an important determinant of the anterograde transport of LE and neurite growth. The impairment of this system may be responsible for the pathogenesis of HSP. Topic: Developmental Neurobiology


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ROLE OF R-RAS1 AND R-RAS2 IN CENTRAL NERVOUS SYSTEM MYELINATION

M. Sanz Rodríguez 1, J. Escudero Ramírez 1, F. de Castro Soubriet 3, J.M. Delgado García4, A. Gruart i Massó4, F. Wandosell Jurado 2, B. Cubelos Álvarez 1 1 . Universidad Autónoma de Madrid-Centro de Biología Molecular Severo Ochoa, Madrid, Spain 2 . Consejo Superior de Investigaciones Científicas-Centro de Biología Molecular Severo Ochoa, Madrid, Spain 3 . Instituto Cajal, Madrid, Spain 4 .Universidad Pablo de Olavide, Sevilla, Spain

A correct myelination is essential for the rapid and effective transmission of the information throughout the axons. Myelin modifications will alter their capability to transmit these electric impulses generating serious pathologies. Establishing the molecular bases underneath myelination processes constitutes an important challenge in our society. In the Central Nervous System (CNS), oligodendrocytes (OLs) are the unique cell type responsible of myelination. This is a complex process where two principal pathways PI3K/AKT and MAPK have been described, although, little is known about the common mechanisms that regulate them orchestrating a correct myelination. In this study we demonstrate that R-Ras1 and R-Ras2, two members of the Ras-Related subfamily, are mutual activators upstream these pathways. In adult mice, both are expressed by OLs and the lack of these proteins leads to a decrease in the number of oligodendrocytes present in the principal myelinated tracts of the CNS. This decrease in OLs population is accompanied with a severe reduction in the thickness and total amount of myelin. These defects correlate with an abnormal delay of the response of Lateral Geniculate Nucleus (LGN) neurons upon light stimulation. Furthermore, in vitro, R-Ras1-/- and/or R-Ras2-/- null mice present OLs with aberrant morphologies, unable to differentiate correctly. Together these results suggest that R-Ras1 and RRas2 play an essential role in oligodendrocyte survival and differentiation being a key element in myelination. Topic: 1 Neuronal excitability, synapses and glia: cellular mechanisms 5 Disorders and nervous system repair


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CHARACTERIZATION OF CASPASE 3 TH-IRES-CRE MICE

I. García-Domínguez 1, J. García-Revilla 1, MA. Roca-Ceballos 1, A. Carrillo-Jiménez 1, AM. Espinosa-Oliva1, R. RuízLaza1, M. Santiago-Pavón1, AJ. Herrera-Carmona1, R. Martínez-de Pablos1, JL Venero-Recio1 1 Facultad de Farmacia. Universidad de Sevilla, Sevilla.

Introduction: Parkinson’s Disease (PD) is the second higher prevalent neurodegenerative disease which curse with motor impairment and the death of dopaminergic neurons in the substantia nigra (SN). However, very few is known about the onset of the disease and though some hypothesis has been proposed, no pathway has been identify that cause the death of the dopaminergic neurons. Our group was a pioneer in identifying non-apoptotic roles of caspases -8 and 3/7 in the CNS demonstrating a caspase-dependent mechanism governing microglia. Our purpose is not only to continue studies about non-apoptotic role of caspase-8/3 in the control of brain inflammation, but to extend them to neuronal phenotypes involved in PD. For this purpose we have generated mice with a specific gene deletion of caspase 3 within catecholaminergic cells. Through behavioral, molecular and cellular analysis on this animal model we intended to understand the role of caspase 3 in the dopaminergic system. Material and methods: We generate this novel animal model consisting in a specific deletion of caspase-3 only in dopaminergic neurons by loxP-Cre recombinase method. We performed the characterization of these animals including dopamine levels in striatum by HPLC, levels of main dopaminergic proteins in SN by RT-PCR, motor status by behavioural tests and the study of nigro-striated system by immunohistochemistry and stereology. Results: Genotyping indicated that there was an effective deletion of caspase 3 gene in mice. Moreover our results showed increased levels of main dopaminergic proteins and also pointed out higher levels of dopamine, what could induce changes in behaviour. Conclusions: Our results suggest that caspase-3 could be implicated in the curse of PD. We have been able to generate a line of mice lacking caspase 3 only in dopaminergic cells, which open the field to future studies on the role of this protein in PD. 1. Developmental Neurobiology


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NOVEL FUNCTION OF TAU IN REGULATING THE EFFECTS OF EXTERNAL STIMULI ON ADULT HIPPOCAMPAL NEUROGENESIS

Noemí Pallas-Bazarraa,b; Jerónimo Jurado-Arjonaa,b; Félix Hernándeza,c; Jesús Ávilaa,b; María Llorens-Martína,b,c a Centro de Biología Molecular “Severo Ochoa”, CBMSO (CSIC-UAM). Madrid, Spain. b Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED, ISCIII). Madrid, Spain. c Faculty of sciences, Universidad Autónoma de Madrid. Madrid, Spain.

Introduction: Tau is a microtubule-associated protein found mainly in axons. However, its presence in dendrites and dendritic spines has acquired special relevance due to its involvement in synaptic plasticity. One of the most drastic examples of plasticity in the brain is the addition of new neurons to a preexisting circuitry during the adulthood. Noteworthy, the addition of new neurons to the hippocampal circuit (adult hippocampal neurogenesis) is regulated by numerous external factors, thus conferring an outstanding degree of plasticity to the network. Interestingly, alterations in adult hippocampal neurogenesis appear to be a relevant neuropathological feature of a group of neurodegenerative diseases known as tauopathies, characterized by impaired Tau metabolism. Thus, we aimed to investigate the role of Tau in the regulation of this process exerted by both stimulatory and detrimental external stimuli. Methods: We used a Tau knockout mice model (Dawson et al., 2001) to analyze the generation and maturation of newborn neurons in the dentate gyrus. We used environmental enrichment (EE) and acute stress as stimulatory and detrimental external stimuli, respectively. Results: The results showed that Tau plays a novel in vivo role in the morphological and synaptic maturation of newborn granule neurons under basal conditions. Furthermore, we also demonstrate that Tau protects newborn neurons from the stress-induced dendritic atrophy and loss of postsynaptic densities (PSDs). Strikingly, Tau also regulates the effects of EE, since newborn granule neurons from Tau knockout mice do not show any stimulatory effect on dendritic development or on PSD generation. Conclusions: This work demonstrates a novel role of Tau in the maturation of newborn granule neurons in vivo under basal conditions. Furthermore, we provide evidence that Tau regulates the effects of external stimuli on adult hippocampal neurogenesis, since newborn granule neurons from Tau knockout mice are insensitive to the modulation exerted by both stimulatory and detrimental stimuli. PUBLICATION: Novel function of Tau in regulating the effects of external stimuli on adult hippocampal neurogenesis. EMBO J. 2016 May 19.Pallas-Bazarra N, Jurado-Arjona J, Navarrete M, Esteban JA, Hernández F, Ávila J4, Llorens-Martín M4. BIBLIOGRAPHY: Dawson HN, Ferreira A, Eyster MV, Ghoshal N, Binder LI, Vitek MP (2001). J Cell Sci 114: 1179-1187


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EXTENSIVE BRANCHING OF RADIALLY-MIGRATING NEURONS IN THE MAMMALIAN CEREBRAL CORTEX Alexandre Espinós1, Maria Ángeles Martínez-Martínez1, Gabriele Ciceri1, Virginia Fernández1, Oscar Marín1,2* and Víctor Borrell1* (1) Instituto de Neurociencias, Consejo Superior de Investigaiones Científicas & Universidad Miguel Hernández San Juan de Alicante, Spain (2) MRC Centre for Developmental Neurobiology (CDN) in the School of Biomedical Sciences, King´s College London, United Kingdom.

During embryonic development, excitatory neurons of the cerebral cortex migrate radially from their place of birth to their final position in the cortical plate. Defects in radial migration lead to severe cortical malformations with as loss of lamination and of cortical folding, usually accompanied by epilepsy. Neurons undergoing radial migration exhibit a single leading process that directs the direction of their movement. This leading process has been classically described as being unbranched, and the formation of branches proposed to impair radial migration. Here we have analyzed in detail the occurrence of leading process branching in radially-migrating excitatory neurons, and the impact of this feature on radial migration dynamics. We have analyzed mouse and ferret to identify potential differences between cortices that undergo folding (ferret) or not (mouse). We find that in the mouse cortex 50% of radially-migrating neurons exhibit a branched leading, raising to 65% in ferret. In both species, branched processes are less parallel to radial glia fibers than those without branches, suggesting some independence from radial glia. Time-lapse imaging under 2-photon microscopy allows us to determine that a vast majority of neurons branch their leading process at some point during radial migration and, importantly, this does not reduce their migration speed. We have tested the functional impact of exuberant leading process branching by expressing a dominant negative Cdk5. We find that loss of Cdk5 function significantly impairs radial migration, but this seems independent from the increase in branch number. We propose that excitatory neurons, similar to interneurons, may branch their leading process as an evolutionary mechanism to allow cells change their trajectory of migration and disperse laterally. Accordingly, increased branching in gyrencephalic species may favor the tangential dispersion of radiallymigrating neurons and cortical folding.


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EMBRYONIC THALAMIC CALCIUM WAVES PREDATE CORTICAL MAP FORMATION

Antón-Bolaños N, Gezelius H*, Pérez-Saiz L, Martini F J, Filipchuk A, Espinosa A, Sempere-Ferràndez A, LopezAtalaya JP, Valdeolmillos M and López-Bendito G Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas (UMH-CSIC), Sant Joan d’Alacant, Spain *Science for Life Laboratory, Tomtebodavägen 23A,17165 Solna, Sweden

Sensory systems are represented in the primary sensory areas of the brain, organized in anatomical and functional maps, as the whisker pad representation in the barrel field of S1 in rodents. Many intrinsic and extrinsic factors have been proposed to shape sensory maps during early development. One of them could be the thalamic spontaneous calcium waves which propagate from the thalamus to the cortex during prenatal stages, before sensory maps are formed. Despite recent evidences supporting this possibility, the role of prenatal spontaneous thalamic activity in cortical map formation remains to be elucidated. To this end, we developed a mouse model (Thkir) in which thalamic neurons are hyperpolarized due to the overexpression of kir2.1. Thkir mice show a disruption of prenatal thalamic spontaneous calcium waves and lack the somatosensory map representation in the cortex. Remarkably, the thalamocortical axons (TCAs) reach their cortical target, nonetheless do not segregate in cortical barrel-like patches as observed in control mice, lacking their characteristic point-to-point refined organization. To unfold whether these topographical defects are controlled by gene expression changes, we performed genome-wide transcriptomic analysis at different embryonic stages. Also, we tested to what extent the lack of a somatotopic map alter the function of the somatosensory system. In vivo extracellular recordings upon whisker stimulation show a clear reduction of the cortical responses in S1, being in agreement with a decrease of whisker-specific Fos induction after novelty exposure in Thkir mice. Thus, by generating a mouse model in which prenatal spontaneous calcium waves are suppressed in the thalamus, we disrupt the formation and function of the barrel-field map in the somatosensory cortex. Our results suggest that cortical somatosensory map formation rely on the spontaneous calcium waves of the thalamus, giving a main role to the prenatal thalamic activity during cortical acquisition of sensory map representations.


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DIFFERENTIAL DISTRIBUTION OF NITRIC OXIDE SYNTHASE (INDUCIBLE AND NEURONAL ISOFORMS) IN FMR1-KNOCKOUT MICE: PATHOPHYSIOLOGICAL ROLE IN THE FRAGILE X SYNDROME RM. Giráldez-Pérez1, Y. de Diego-Otero2,3 1 Facultad de Biología, Universidad de Sevilla. Sevilla. España 2 UGC Salud Mental, Hospital Regional Universitario de Málaga. Málaga. España 3 Instituto de Investigación biomédica de Málaga IBIMA, Málaga. España

Background: Nitric oxide (NO) is a signaling molecule with very important physiological functions in the nervous system. NO is synthesized by three different isoforms of nitric oxide synthase, which are present in the central nervous system. High levels of NO production react with reactive oxygen species (ROS) to form highly reactive intermediates that contribute to oxidative damage and nitroxylation of proteins. Abnormal NO signals are thought to contribute to a variety of nervous system pathologies, such as intellectual disability, Alzheimer's disease, multiple sclerosis and Parkinson's disease, among others. Material and methods: Immunohistochemical techniques were performed in 4 mice per genotype (Fmr1-KO and wild-type (WT)-control mice) to determine differential distribution of the neuronal NOS and inducible NOS isoforms. Results: Differential distribution of iNOS was found in Fmr1-KO mice versus WT-controls. A significant iNOS positive signal was detected in the CA3, CA1 subiculum zone and subgranular layer of the dentate gyrus, in Purkinje cells of the cerebellum, neurites in the molecular and subgranular layers, vestibular and lateral vestibular nuclei. As well as anterior areas of the cortex. Moreover, differential distribution of nNOS was found in WT-control mice versus Fmr1-KO. The Fmr1-KO mice have a higher number of positive cells in the dentate gyrus of the hippocampus, the Purkinje layer of the cerebellum and in striatal areas. Conclusions: The Fmr1-KO mice show a differential immunohystochemical positive signal of the iNOS and nNOS enzymes in brain regions involved in cognitive tasks and movement control. Work supported by the Ministry of health (TRA152, EC10-191, EC11-434). Andalusian Ministry of Health (PI2009-0507) and Andalusian Ministry of Innovation (CTS-546, P10-CTS-05704). European Regional Developmental Fund (FEDER-EU).


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NG2-GLIA HETEROGENEITY IN THE MICE BRAIN A. Bribián1, R. Sánchez-González 1, and L. López-Mascaraque1 1. Instituto Cajal-CSIC, Madrid, Spain.

NG2-glia, are the most enigmatic neural population in the central nervous system. Homogenously distributed in all regions of the adult brain and organized in a network-like manner they are maintained as a resident population, by self-renewal. NG2-glia is the only proliferating cells in the adult healthy central nervous system outside the neurogenic/stem cell niches, although their potential as progenitors remains controversial. These cells are of particular interest, since they still retain some multipotency, being able to differentiate into fully mature myelinating oligodendrocytes, and, under some circumstances, into functional neurons and astrocytes. Moreover, during development NG2-cells are generated from multiple sources, starting from the ventral (subpallial) ventricular zone at early stages to dorsal (pallial) regions at later and postnatal stages. Thus, NG2-glia conforms a heterogeneous population, although it is still unclear whether this cellular heterogeneity emerges during development. In particular, our work is focused on the disclosure of the lineage potential of single-NG2 cells and their clonally related-cell progeny during development and adulthood. At this end, we modified StarTrack plasmids directed to permanently label the progenitor cell and all its NG2 cell progeny related to their origin and embryonic stage. With this strategy, we reveal some of the basis of the heterogeneity of NG2 cells and their progeny. These new data will provide a more comprehensive understanding of the progenitor cell fate potential to progress in future studies directed toward promoting brain repair. Supported by research Grant BFU2016-75207-R from MINECO 1 Neurobiología del Desarrollo 2 Nuevos métodos y tecnologías


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TOWARDS A MODEL OF SIX PALLIAL DIVISIONS? A. Abellán , E. Desfilis, L. Medina Facultat de Medicina. Universitat de Lleida, IRBLleida, Lleida, Spain

The combinatorial expression patterns of regulatory genes, studied under the scope of the evolutionary developmental biology, have become crucial for identifying homologous pallial divisions and understanding their evolution. This approach led to a change of paradigm, moving to a tetrapartite model, with newly defined ventral and lateral pallial sectors, which were suggested to produce different parts of the claustrum, pallial amygdala and piriform cortex. This model was recently updated and, based on genetic fate mappings, it now appears that only the ventral pallium but not the lateral pallium - produces cells for the pallial amygdala. However, the tetrapartite model is currently facing problems for explaining the origin of pallial structures at the caudal pole of the telencephalic hemispheres (a region often ignored in gene expression studies). These problems also interfere with attempts for trying to find homologues of that caudal region in the pallium of nonmammals. In order to solve these problems, we studied the expression of a battery of developmental regulatory genes in the embryonic brain of mouse and chicken using in situ hybridization, paying special attention to the caudal levels. Our results helped to identify two novel caudal pallial sectors, different from the medial, dorsal, lateral, and ventral pallium. The new sectors are a dorsolateral caudal pallium (expressing Emx1 and Jag1, but not markers defining other pallial sectors as Lef1, Dbx1, COUP-TF2, Sfrp2, ER81, and FoxP1), related to the lateral entorhinal cortex, and a ventrocaudal pallium (expressing Emx1, Lhx9, COUP-TF2, and Zic2, but not Lef1, Dbx1, Sfrp2, ER81, and FoxP1), producing the posterior pole of the pallial amygdala. The newly defined sectors may provide a useful framework to test questions on their evolution and their derivatives, and may contribute to understand the expansion of the entorhinal cortex and the pallial amygdala in some mammals, such as primates. Sponsor: MINECO and FEDER, grant no. BFU2015-68537-R Topic: 1. Developmental Neurobiology


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A MOUSE MODEL OF DYRK1A-RELATED INTELLECTUAL DISABILITY SYNDROME SHOWS ALTERED GLIOGENESIS AND DEFECTS IN MYELINATION I. Pijuan Jiménez 1,2, E. Balducci 1, E. Fernández Jover 3, M.J. Barallobre Filgueira 1,2, M. Arbonés de Rafael 1,2 1 . Instituto de Biología Molecular de Barcelona (IBMB) – CSIC, Barcelona, Spain 2 . Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Barcelona, Spain 3 . Universidad Miguel Hernández, Elche, Spain

Introduction: Individuals with de novo mutations in DYRK1A present microcephaly and intellectual disability (ID), in most cases accompanied with astrogliosis and hypomyelination. Human DYRK1A is located in chromosome 21 and its triplication contributes to the neurological alterations associated to Down syndrome (DS). DYRK1A encodes a protein kinase with a conserved function across evolution in the developing brain where it regulates neurogenesis and neuronal survival and differentiation. There is evidence that the overexpression of DYRK1A contributes to the astrogliosis associated to DS. However, the role of DYRK1A in gliogenesis or glial cell function has not been studied. Results: Here we show that adult haploinsufficient Dyrk1a+/- mice phenocopy the ID-related DYRK1A syndrome exhibiting an increased number of astrocytes in the telencephalon and altered myelination of the corpus callosum, alterations that arise early in development. Neural progenitors isolated from Dyrk1a+/- embryos show an altered capacity to differentiate into astrocytes and oligodendrocytes. In vivo, an excess of cortical astrocytes in the Dyrk1a+/- model is evident one week after birth. In contrast, at perinatal stages, there is a deficit of oligodendrocyte precursors in the corpus callosum, which is due to a reduced embryonic oligodendrogenesis. After the second postnatal week the population of oligodendrocytes reaches normal numbers in Dyrk1a+/- mice. However, they show a defect in myelination that persists in the adult. Conclusions: Our results suggest a new role of DYRK1A in glial cell development that could contribute to the ID and other neurological problems in patients carrying heterozygous mutations in the DYRK1A gene. Topic: 1. Developmental Neurobiology


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ECTOPIC NETWORKS IN THE SUBCORTICAL WHITE MATTER OF DEVELOPMENTAL HYPOTHYROID RATS. AN IMMUNOHISTOCHEMICAL AND EM STUDY F. Lucia-Curt 1, S. González-Granero 2, M.M. Moreno-Camuñas 1, J.M. Garcia-Verdugo 2 and P. Berbel 1. 1 . Universidad Miguel Hernández, Sant Joan d’Alacant, Alicante, España. 2 . Instituto Cavanilles, Universidad de Valencia, CIBERNED, Valencia, España.

One of the principal alterations caused by gestational hypothyroidism is the alteration of radial and tangential neuron migration during corticogenesis. This alteration causes abnormal cortical layering and ectopic neurons in the white mater of the neocortex and alveus of the hippocampus. Usually, these ectopic neurons are scattered, but in a few cases they can be grouped, forming a neural mass of cells surrounded by white mater axons. The cytoarchitecture of these ectopic networks is poorly understood. Our aim was to study this cytoarchitecture using immunohistochemistry and electron microscopy. A total of 11 ectopic networks were studied from hypothyroid rats collected over a period of several years. Hypothyroidism was induced with 0.02% methimazole treatment (from embryonic day 10 (E10) until day of sacrifice) and 1% KClO4 (from E10 to postnatal day 21 (P21)). Sacrifice age ranged from P100-P170. Immunostained NeuN, GAD65/67, calretinin, parvalbumin, SMI31, VGluT1 and VGAT thick-sections, and toluidine blue semi-thin and ultrathin araldite-embedded sections were studied. Ectopic networks were found in the medial and caudal neocortical regions, between the subcortical white matter and the hippocampal commissure/alveus. They measured on average 800 (anteroposterior) x 300 (medio-lateral) x 100 (dorso-ventral) µm, contained 55±9 NeuN+ neurons/10,000 µm2, medium-small vessels and SMI31+ axons. GAD65/67+ (10%), calretinin+ (1%) and parvalbumin+ (5%; originating numerous perisomatic boutons) neurons were scarce. 76% of neuropil boutons were VGluT1+, being homogenously distributed, while the VGAT+ boutons were mostly perisomatic (24%). Neurons (10x8µm, on average) showed a large nucleus (7x5µm, on average) with a prominent nucleolus. They had scattered rough endoplasmic reticulum, numerous polyribosomes and perisomatic symmetric and asymmetric synapses. Our data show that gestational TH deficit can induce the formation of organized ectopic networks. The function of these networks remains unclear but they may be related to the neurological diseases frequently associated to hypothyroidism. ALICIA KOPLOWITZ Foundation, MINECO-SAF2014-58256-R, GV-PROMETEOII/2014/075.


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DISTRIBUTION OF GABAB RECEPTORS AND THEIR AUXILIARY SUBUNITS KCTD8, 12 AND 16 IN THE DEVELOPING MOUSE BRAIN

A. Fajardo-Serrano1, R. Luján1 1 . Instituto de Investigación en Discapacidades Neurológicas (IDINE), Facultad de Medicina, Universidad de CastillaLa Mancha Albacete, Spain.

GABAB are the G-protein-coupled receptors for GABA that activate Gαi/0 and regulate ion channels via Gβγ. Presynaptic GABAB inhibit voltage-gated Ca2+ channels, whereas postsynpatic GABAB activate inwardly rectifying K+ channels (GIRK). GABAB are formed by two subunits: GABAB1 and GABAB2 and constitutively associate with homotetramers of K+ channel tetramerizationdomain (KCTD). KCTDs are cytoplasmatic proteins that bind to GABAB2 and the Gβγ subunits generating distinct receptor subtypes and regulating the receptor through GABAB2 and/or the Gprotein. The expression of KCTD subtypes in different regions during brain development is unknown. We used a histoblot technique to analyze the regional localization of GABAB1, GABAB2, KCTD8, KCTD12 and KCTD16 in the mouse brain at different postnatal ages. GABAB1 and GABAB2 immunoreactivity increased with the age. In the cerebellum, a significant increase from P0 to P60 was observed. GABAB1 and GABAB2 subunits show high expression in the CA3 region of the hippocampus and thalamus, there is less expression in the caudate putamen. However, the expression of their auxiliary subunits KCTD8, 12 and 16 in the brain differs in a subunit- and region-dependent manner. Thus, in the cerebellum KCTD8 showed a strong immunoreactivity at P0, while KCTD12 was weak at that age, increasing considerably at P5. The expression of KCTD16 was low at all ages. In the hippocampus, KCTD8 showed low expression at different stages; KCTD12 showed strong expression, mainly at P5 and P10, whereas KCTD16 showed low expression at P0 and P5, increasing after P10. In the thalamus and caudate putamen the expression of KCTD8 and KCTD12 was low but there was strong expression of KCTD16 at P21. The results show that the auxiliary subunits of GABAB receptors showed differential expression and distribution patterns in the postnatal brain, suggesting GABAB receptors associate to different KCTD proteins in a cell type-, brain region- and age-dependent manner. Support: MINECO BFU2015-63769-R


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THE ROLE OF P27KIP1 IN THE DEVELOPMENT, DIFFERENTIATION AND MATURATION OF MESENCEPHALIC DOPAMINERGIC NEURONS C. Palmer1, A. Bernabeu-Zornoza1, R. Coronel1, M. Lachgar1, L. Silva1, N. Jiménez-Téllez1, C. Gil1, M. Serrano2, I. Liste1 1 . Unidad Funcional de Investigación de Enfermedades Crónicas (UFIEC), Instituto de Salud Carlos III (ISCIII), Majadahonda, Madrid, Spain. 2. Centro Nacional de Investigaciones Oncológicas (CNIO), Madrid, Spain.

Parkinson’s Disease (PD) is one of the most common neurodegenerative disorders, generally characterized by the loss of specific dopaminergic neurons (DAn) in the midbrain. Current treatment options are available to help relieve primary motor symptoms, but their long-term effectiveness is limited. For this reason, alternative treatment options are being sought in the form of stem cell replacement therapies. Pluripotent stem cells, known for their ability to self-renew and differentiate into any cell lineage of the three germ layers, are a popular source of cells for the differentiation of DAn. In our lab, we are investigating the role of the protein p27Kip1 (p27) in the differentiation process of these types of neurons. p27 is a cyclin/cyclin dependent kinase inhibitor (CKI) belonging to the Cip/Kip family of proteins, best known for its function in the cell cycle. In this work, we investigate and analyze the effects of p27 on the development, differentiation and maturation of dopaminergic neurons in vivo and in vitro, using standard techniques of immunocytoand histochemistry, western blot and quantitative-PCR. Our preliminary results show that mouse induced pluripotent stem cells that lack the protein p27 has led to a significant decrease in the production of TH+ (tyrosine hydroxylase, the limiting enzyme in dopamine production) cells, while the opposite effect was seen in mouse embryonic stem cells nucleofected to overexpress p27. In vivo, we have seen that at embryonic age E13.5, the production of TH in p27 knock-out mice was greatly reduced compared to wild type controls. We are currently doing a deeper analysis of other markers important for proper dopaminergic neuron development to decipher the mechanistic effects of p27. This would allow us to better apply the use of this protein to improve current differentiation protocols of dopaminergic neurons for stem cell replacement therapies in Parkinson’s Disease.


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ZIC2 MODULATES ß-CATENIN LEVELS TO PROMOTE AXON MIDLINE REPULSION C. Morenilla-Palao, J. López-Atalaya, A. Barco, E. Herrera Instituto de Neurociencias (CSIC-UMH) Alicante, Spain.

In species with bilateral symmetry neural circuits containing ipsilateral and contralateral tracts distribute sensory information coming from both sides of the body to integrate it in the main processing centers of the brain in order to generate coordinated motor responses. The transcription factor Zic2 specifies axonal ipsilaterality in at least two different types of neurons, retinal ganglion cells (RGCs) and spinal neurons but through the expression of two different tyrosinekinase receptors, EphB1 in the visual system and, EphA4 in the spinal cord. Here, we aimed to further identify Zic2 targets in an unbiased manner and explore to what extent this transcription factor shows a similar binding profile in different neural types. Our genomic screens revealed that, with few exceptions, Zic2 binds to the same genomic regions in both types of differentiated neurons. Furthermore, Gene Ontology (GO) analyses evidenced that Zic2 binds to the promoter region of many genes involved in the Wnt-signalling pathway. Consistent with this observation, functional experiments revealed that Zic2 enhances the accumulation of ß-catenin, the main read out of the Wnt-signalling pathway. The ectopic accumulation of ß-catenin in growing RGC axons triggered axon midline avoidance independently of downstream transcriptional events, suggesting that the turning of visual axons at the midline induced by accumulation of ß-catenin does not depend on the canonical Wnt-signalling pathway. Instead, our experiments suggest that activation of EphB1 at the growth cone triggers a compartment-confined phosphorylation of ß-catenin, favouring the non canonical Wnt-signalling pathway. Together, these results indicate that in differentiated neurons Zic2 and its tyrosine-kinase effectors modulate the local levels of ß-catenin at the growth cone to control axonal laterality in the CNS.


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FGF8 SIGNALING REGULATES THALAMIC NUCLEAR REGIONALIZATION AND THALAMO-CORTICAL PROJECTION

A. Botella-López 1, A. Pombero 2*, R. García-López2*, A. Estirado2, O. Bahamonde4, S. Martínez 1,3 1 . Instituto de Neurociencias. UMH-CSIC, San Juan de Alicante. 2 . IMIB-Arraixaca, Universidad de Murcia, Murcia 3 . Centro de Investigación Biomédica En Red en Salud Mental (CIBERSAM) 4 . Biobanco INCLIVA Hospital Clínico de Valencia-Universidad de Valencia, Valencia (*) These authors have contributed equally to this work

Thalamocortical projection (TC) constitutes a topologically-ordered projection that conveys information of voluntary motor plans and sensory modalities from specific thalamic nuclei to functional areas in the cerebral cortex, representing the key system of conscious body-brain connection. Since thalamic neurons are structurally homogenous, their functional complexity derived from TC is a consequence of synaptic specificity. The adequate development of thalamocortical axons depends on guide signals that bind membrane receptors in axonal growth cones; receptors that are regulated by thalamic regionalization. In this work, the role of Fgf8 morphogenetic signaling in the establishment of a neuronal thalamic protomap was studied, which is revealed by the expression of Igsf21, Pde10a and Btbd3 genes in the thalamic mantle layer. Fgf8hypomorphic mouse presented thalamic protomap disorganization and specific cellular death in relation to Fgf8's signaling gradient, as well as a strong disruption of TC. In conclusion, Fgf8 encoded the positional information required for thalamic nuclear regionalization and the expression of guidance cues controlling TC pathfinding to the cortex. Topic: 1. Developmental Neurobiology


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STUDY OF NEUROVASCULAR NICHE IN DENTATE GYRUS IN FGFR1 MUTANT MICE R. Garcia-Lopez1*, A. Pombero1*, A. Estirado1, S. Martínez2,3 1 IMIB-Arraixaca, Universidad de Murcia, España 2 Instituto de Neurociencias, UMH-CSIC, España 3 Centro de Investigación Biomédica En Red en Salud Mental (CIBERSAM) * These authors contributed equally to this work

The concept of neurogenic niche in the brain proposes a functional unit between the precursor cells and their local microenvironment. Neural stem cells in the neurogenic areas proliferate in groups close to the perivascular space where their self-renewal and differentiation is regulated. The central nervous system pericytes have been recognized as an indispensable component of the neurovascular unit (NVU). In the hippocampus, this is important for providing an optimal microenvironment for neural proliferation. Hippocampal neurovascular regulatory system include both diffusible signals and direct contact with endothelial and pericytes, which are a source of diffusible neurotrophic signals such as VEGF and FGFs, that affect neural precursors. One of the key growth factors that regulate postnatal neurogenesis in hippocampus is fibroblast growth factor-2 (FGF-2, also called basic FGF). FGF2 is expressed by endothelial and periendothelial cells (pericytes) and FGF2 deficiency produces a decrease of neural proliferation in the dentate gyrus. Interestingly, hippocampal neural precursors express Fgfr1, the major receptor for FGF2 and its absence leads to a decrease in neurogenesis accompanied by a severe impairment of long-term potentiation and memory consolidation. Previous studies suggest that FGFs act directly on hippocampal stem cells. Since FGF-2 is a potential regulator in neurogenesis and angiogenesis crosstalk, we propose to describe the precise role of FGF signal in NVU development in the hippocampus by studying whether the neurovascular niche is altered in FgfR1 mutant mice. In order to address it we focused on pericytes and endothelial cells to detect vascular abnormalities during development, and subsequent anomalies in neuro-epithelial specification, migration and differentiation of hippocampal granular cells and neurogenic niche in the dentate gyrus. Topic: Select the topic which best fits to your paper. 1. Developmental Neurobiology


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ROLE OF miRNAS IN BRAIN EARLY DEVELOPMENT

V. Fernández-Martínez1, M. A. Martínez-Martínez1, U. Tomasello1, M. Dori2, F. Calegari2 and V. Borrell1 1 . Developmental Neurobiology Unit, Institutode Neurocienciasde Alicante, C.S.I.C.-U.M.H., SantJoan d’Alacant, Alicante, Spain 2 . DFG-Research Center for Regenerative Therapies Dresden -Cluster of Excellence (CRTD), Dresden, Germany

During early telencephalic development a small domain of progenitors in the rostral pallium initiates a developmental program different from the nearby pallium causing a marked tissue growth and evagination, leading to the eventual formation of the olfactory bulb (OB). The cellular and molecular mechanisms regulating this specialization of rostral pallial progenitors into generating the OB, as opposed to the neocortex, remain largely unknown. Here we tested the potential role of miRNAs in controlling the behavior of OB progenitor cells using a Dicerflox/flox;Rx-Cre mouse, deficient in Dicer-dependent miRNAs since the onset of telencephalic development. We find that the absence of miRNAs from very early stages of brain development causes deficits in OB formation and growth, which is much smaller than in WT littermates. Rx-Dicer mutants display a high frequency of cell death from early stages (E10.5E12.5), predominantly affecting Pax6+ progenitor cells and coincident with the peak of OB neurogenesis. At later stages (E13.5-E17.5) this deficit is gradually compensated by hyperproliferation and the formation of rosette-like structures in the basal telencephalon. RNA sequencing analysis of the primordium of the OB (pOB) from WT and Dicer KO embryos shows a loss of let-7 family miRNas together with an upregulation of genes involved in apoptosis (p53 pathway) and proliferation (like IRS-2) in Dicer mutants. Finally we show how deleting functional p53 in Dicer KO animals, there is no rosette formation and furthermore, performing GOF experiments of IRS-2 by IUE we can generate rosette-like structures in the rostral telencephalon. Our results demonstrate a crucial role of let-7 miRNAs during rostral telencephalon development, controlling oncogenic cascades that includes both apoptosis and cell proliferation. Topic: 1. Developmental Neurobiology


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IDENTIFYING SPONTANOUS ACTIVITY-DEPENDENT MECHANISMS IN VISUAL CIRCUIT FORMATION Santiago Negueruela, Cruz Morenilla-Palao, Danny Florez-Paz, Ana Gomis and Eloísa Herrera Instituto de Neurociencias (CSIC-UMH) Alicante, Spain.

Experimental and computational studies have defended for decades that activity-independent events and activity-dependent mechanisms play complementary but independent roles in the formation of precise neural circuits during neural development. However, accumulating evidence now indicate that spontaneous correlated activity influences the expression and function of molecules involved in early developmental stages such as axon guidance or targeting. To address the relative contribution of spontaneous activity-dependent mechanisms in shaping initial connectivity during brain development we have genetically manipulated the visual system of mice to disturb the transmission of spontaneous waves of correlated activity in the retina and searched for molecules responding to this disruption. We have generated a transgenic mouse line that conditionally expresses the rectifying potassium channel Kir2.1 and crossed it with two different Cre-lines, one specific for retinal ganglion cells (RGCs) (Pou4f2-Cre) and one for ipsilateral RGCs (Slc6a4-Cre). We first confirmed that RGCs from these two transgenic mouse lines ectopically express Kir2.1 which caused larger inward-rectifying currents, more negative resting potentials and an alteration of the electrical activity pattern. Then, we analyzed the terminals of retinal axons at the visual nuclei and observed severe defects in segregation and refinement which are maintained in the adult animal and cannot be rescued by visual stimuli. We are now comparing RNA-seq profiles of RGCs from Kir2.1-overexpressing mice and their controls to search for new correlated spontaneous activitydependent transcripts that may contribute to axonal remodelling during postnatal refinement.


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ROLE OF SEMA3E/PLEXIND1 IN THE DEVELOPING AND ADULT HIPPOCAMPAL FORMATION

A. Mata1,2,3,4, V. Gil1,2,3,4, J. Pérez-Clausell2, E. Soriano2,3,4,5,6 and J.A. del Río1,2,3,4 1 Institute for Bioengineering of Catalonia (IBEC), Parc Científic de Barcelona, Barcelona, Spain. 2 Dept. Biología Celular, Fisiología e Inmunología, Universitat de Barcelona, Barcelona, Spain. 3 Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED) 4 Institut de Neurociències de la Universitat de Barcelona. Barcelona, Spain. 5 Vall d'Hebrón Institut de Recerca (VHIR), Barcelona, Spain. 6 ICREA Academia, Barcelona, Spain.

Introduction: The hippocampal formation is a well organized architecture: principal cells are

located in single layers and afferents (entorhinal and commissural/associational axons) are distributed in well defined lamina. The development and axonal wiring of the hippocampal formation depends on the action of numerous axon guidance cues. Among others, Class III Semaphorins are difussible molecules with crucial roles during hippocampal and neocortical development. Although the role of several members of the family is well described, little is known about the roles of Sema3E and its high affinity receptor, PlexinD1, during the development of the hippocampal formation and in the adult. Materials and methods: We have been able to analyze the expression patterns of Sema3E and PlexinD1 in the developing and adult hippocampal formation of wild-type mice. We developed cocolture experiments in vitro to study how the entorhinal axons of the developing hippocampal formation behave in presence of Sema3E. In addition, we analyzed the development of the entorhino-hippocampal connection at early postnatal stages in presence or absence of Sema3E or PlexinD1, by using KO and lox mice respectively. Lastly we have analysed the citoarchitecture and alterations of the hippocampus in their adult stages. Results and conclusions: Our results demonstrate that: 1) Sema3E/PlexinD1 play a role in the development of the entorrino-hippocampal connection by inhibiting entorhinal axons. 2) Absence of Sema3E/PlexinD1 signalling triggers the aberrant layering of entorhinal axons in the hippocampus. 3) Absence of Sema3E/PlexinD1 signalling in the adult misorganizes mossy fibers with relevant ectopic fibers in the molecular layer of the dentate gyrus. 4) In addition, the granule cell layer of the dentate gyrus displayed a “wavy” organization due to alteration in the proliferation of dentate precursors and altered position of postmitotic granule cells.


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POTENTIAL MODULATORS OF DIFFERENCES IN COGNITION IN AUTISM SPECTRUM DISORDERS A García Alcón1, 3, E. Weckx2, D. Gerez1, 3, M.J. Penzol1, 3, M. Parellada1, 2, 3 1 . Hospital General Universitario Gregorio Marañón, Madrid. 2 . Facultad de Medicina, Universidad Complutense, Madrid 3 . Instituto de Investigación Sanitaria Gregorio Marañón, Madrid

Background Bibliography reports early environmental factors as potential predictors of the risk of Autism Spectrum Disorders (ASD) [1] and its severity [2]. We identified advanced parental age (APA) as a predictor of lower Intelligence Quotient (IQ) in ASD patients. Lately, scientific community includes parental autism traits as an alternative explanation for delaying age at conception [3]; additionally, is discussing if use of oxytocin in labour induction could account as another potential predictor [4]. We aim to include mentioned factors in our analysis. Methods Ninety-seven patients (mean age 14.68 ±7.6SD, 91.8% male, 94.8% caucasian) with ASD were recruited. Parental autism traits were evaluated with the Autism Spectrum Quotient (AQ). Statistics analyses were used to assess the relationship between parental autism traits and age at conception; and the potential association of proband IQ with the following predictors: parental (APA, psychiatric history and autism traits), birthweight, obstetric complications or labour oxytocin use and epilepsy, regression, and age at autism onset. Results There was not a significant correlation between AQ scores and parental age at birth. Proband IQ (mean 83.21 ±24SD) significantly correlated with maternal and paternal age (r=-.221, p=.032 and r=.305, p=.003, respectively) at birth, labour oxytocin use (t=2.383, p=.021) and age at autism onset (t=2.163, p=.033); a trend value was shown for developmental regression (t=1.846, p=.068). Paternal age at birth and labour oxytocin use appeared as predictors of IQ in the multiple regression analyses, controlling for age, sex and ethnicity (B=-.426, p=.001 and B=-.262, p=.041 respectively; R2=.243). Conclusions APA and labour oxytocin use do partially predict IQ in ASD patients. Contrary to our hypothesis, parental autism traits do not predict IQ outcome. The mechanisms by which APA increases the risk for ASD and its severity needs further investigation. Likewise, the direction of the relationship oxytocin use-IQ in ASD patients is, hitherto, unknown. TOPIC: 1. Developmental Neurobiology BIBLIOGRAPHY:

[1] Kolevzon, Alexander, Raz Gross, and Abraham Reichenberg. "Prenatal and perinatal risk factors for autism: a review and integration of findings." Archives of pediatrics & adolescent medicine (2007) [2] Wallace, Anna E., George M. Anderson, and Robert Dubrow. "Obstetric and parental psychiatric variables as potential predictors of autism severity." Journal of Autism and Developmental Disorders (2008) [3] Gratten, J., Wray, N. R., Peyrot, W. J., McGrath, J. J., Visscher, P. M., & Goddard, M. E.. “Risk of psychiatric illness from advanced paternal age is not predominantly from de novo mutations.” Nature genetics (2016) [4] Smallwood, M., Sareen, A., Baker, E., Hannusch, R., Kwessi, E., & Williams, T.. “Increased Risk of Autism Development in Children Whose Mothers Experienced Birth Complications or Received Labor and Delivery Drugs.” ASN neuro, (2016)


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BRAIN RESTING ACTIVITY IN AN ANIMAL MODEL OF AUTISM. A FUNCTIONAL MAGNETIC RESONANCE IMAGING STUDY

A. Eed, I. Aller, S. Canals, J. Lerma Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas, Universidad Miguel Hernández de Elche, San Juan de Alicante, Spain.

GRIK4 is the gene responsible for encoding the high-affinity GluK4 subunit of the kainate receptors, which has been associated with several psychiatric disorders such as schizophrenia and bipolar disorder. It has been also shown using functional magnetic resonance imaging (fMRI) that healthy individuals with a variant of this gene generating more stable mRNAs and therefore more protein have altered activation of the hippocampus during face-processing tasks. The nature of these alterations is yet to be elucidated. Transgenic animals represent attractive models for further investigating implications of GluK4 in brain performance. Here we studied Grik4 overexpressing mice in the forebrain that show some of the cardinal features of autism such as lack of social interaction, anxiety and depression. Resting-state fMRI was used in these animals to investigate the effects of Grik4 overexpression on the function of different brain circuits. Grik4 overexpressing mice displayed patterns of hyperactivation in parts of the hippocampus as well as some areas of the prefrontal cortex. An extensive loss of interaction strength between the prefrontal cortex and the cerebellum was also observed in the transgenic mice compared to the wild type group. Hyperactivation of the hippocampus, where Grik4 is profusely expressed, in transgenic mice can explain depression as well as the deficit in social interaction that Grik4 overexpressing mice usually experience in comparison to the wild type animals, as hippocampus has long been associated with these behaviors. Disruption of the prefrontal cortex circuits might hold responsible for the high anxiety that the transgenic animals show. In conclusion, our data shed light on the global circuits’ dysfunction and the deleterious effects that might happen due to overexpression of Grik4, a situation that recapitulates autistic children with de novo duplication of this gene, using non-invasive approaches.


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DISSECTING THE NEURODEVELOPMENTAL CONSEQUENCES OF PRENATAL CANNABINOID EXPOSURE: WHEN SEX MATTERS

D. García Rincón1,2*, A. de Salas Quiroga1,2*, J. Paraíso Luna1,2, J. Díaz Alonso3, A. Villarreal1,2, J. Aguareles1,2, M. Pujadas4, C. Muguruza5,6, L. F. Callado5,6, M. Guzmán1,2, I. Galve Roperh1,2 1 . Center for Networked Biomedical Research in Neurodegenerative Diseases (CIBERNED), Institute Ramón y Cajal for Health Research (IRYCIS) and Institute of Neurochemistry (IUIN), Madrid, Spain 2 . School of Biology, Complutense University, Madrid, Spain 3 . University of California, San Francisco, USA 4 . Hospital del Mar Medical Research Institute, Barcelona, Spain 5 . Basque Country University (UPV/EHU), Bilbao, Spain 6 . Center for Networked Biomedical Research on Mental Health (CIBERSAM), Madrid, Spain * Equally-contributing authors

Besides its neuromodulatory role in the adult nervous system, the CB1 receptor is an important regulator of mammalian brain development. Hence, embryonic manipulation of CB1 receptor function results in long-lasting cellular and functional alterations. Previous studies have shown that prenatal disruption of CB1 receptor signaling elicited by THC exposure induces changes on neuronal populations responsible of different behavioral traits and also affects the excitatory/inhibitory balance, as evidenced by the increased seizure susceptibility in adult stages. Now we show that some of the long-term consequences of THC administration exhibit sexual dimorphism. Thus, among the offspring of pregnant, treated mice, male individuals are more susceptible to pentylenetetrazole-induced seizures, not only in comparison with their vehicle-treated counterparts, but also with THC-exposed females. We found that this sex-selective sensitivity to prenatal THC exposure is also present in other traits, such as CB1 agonist-evoked hypothermia or hypolocomotion. In order to explain these findings, we sought to determine whether molecular mechanisms responsible of embryonic THC metabolism or CB1 receptor desensitization might differ among sexes. Unraveling the mechanisms beneath these sexual differences and their psychiatric outcomes will be crucial for the full understanding of the role of CB1 receptor during brain development, as well as for truly addressing the long-term consequences of cannabis abuse during pregnancy. This study (PI15-0310) was supported by the Instituto de Salud Carlos III (Plan Estatal de I+D+i 2013-2016) and cofinanced by the European Regional Development Fund “A way to achieve Europe” (ERDF). Keywords: cannabis, CB1 cannabinoid receptor, prenatal exposure, sex differences, epileptogenesis. Selected topic: Developmental Neurobiology


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MOLLECULAR PARCELLATION OF THE DEVELOPING MOUSE PRETHALAMUS: A GENOARCHITECTONIC APPROACH N. Morales-Delgado1, A. Alonso1, C. Díaz2, A. Ayad1, M. Martinez-de-la-Torre1, J.L. Ferran1, L. Puelles1. 1 . School of Medicine. University of Murcia, Murcia, E30071, Spain. 2 . School of Medicine, University of Castilla-La Mancha, Albacete, E02006, Spain.

Background. The embryonic prethalamus, which originates from the alar plate of prosomere 3, undergoes an anteroposterior and dorsoventral microzonal subdivision pattern. Eventually, these distinct domains give rise to several well-known nuclei that form a continuous shell around the thalamus. At early stages, the Zona Limitans intrathalamica (ZLi), generally defined by alar Shh expression, is the responsible for mediating the regionalization of the prethalamus anteriorly and the thalamus posteriorly. Furthermore, the prethalamus has been supposed to be a relevant and intermediate target for the formation of reciprocal thalamocortical connections. To date, the regionalization of the presumptive mouse prethalamus is scarcely understood and has yet to be unraveled. Objective and Methodology. We analyzed the prethalamic topography by using in situ hybridization images downloaded from the Allen Developmental Mouse Brain Atlas to provide a more detailed genoarchitectonic map of the developing mouse prethalamus. We compared the spatiotemporal expression of well-described regional markers (e.g., Pax6, Isl1, Gad1, Six3, etc) as well as other less known (e.g., Brx1, Ngn2, Linx, etc). Results and Conclusions. In summary, we identified in the alar prethalamic plate: 1) three main rostrocaudal molecular partitions named here yuxtapeduncular, central and prelimitans areas, respectively; 2) three rostrocaudal subdivisions of the ZLi consisting of a main central core flanked by an anterior (related to prethalamus) and a posterior (at thalamus territory) shell, respectively; and 3) four dorsoventral dimensions that comprise the prethalamic eminence and the sequential dorsal, lateral and ventral subareas, respectively. Our preliminary approach provides substantial insights into the basic molecular regionalization plan that underlies the organization of both the prethalamic complex and the narrow ZLi. Furthermore, it would be useful for understanding the complexity of adult distribution and how influences adjacent territories. Supported by Spanish MEC grant BFU2014-57516-P (with EFDR funds support) and Seneca Foundation grant 19904/GERM/15. Topic: Developmental Neurobiology


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THE SUBSTANTIA NIGRA IS AN INTERMEDIATE TARGET OF THE MEDIAL HABENULA AXONS

J. A. Moreno-Bravo1, A. Guerrero-Moreno2, V. Company2, C. Crespo-Quiles2, I. Juarez-Leal2, D. Echevarría2, E. Puelles2. 1 Institut de la Vision. UMR S 968 Inserm, UPMC, CNRS 7210, 17 Rue Moreau, Paris, France. 2 Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-CSIC, Sant Joan d’Alacant, Alicante, Spain.

One of the key processes during central nervous system development is the correct guidance of the axons towards their targets. Some of the fascicles and tracts display extraordinary complex trajectories. These are achieved by long and short range signaling pathways. In the last decade, it has been proved that not only the origin and the target populations are involved but also intermediate target nuclei. They act as traffic pathway signals, indicating the correct way to the growing axons. The medial habenula axons are integrated in the retroflex tract. This fiber tract displays an intricate route. Its axons grow ventrally along the dorsoventral axis, bend caudally in the proximity of the floor plate and travel caudally towards the interpeduncular tract. We and other groups have elucidated partially the signaling mechanism of this trajectory. Nevertheless, the process of caudal bending remains unknown. To research this aspect, we have used the mouse as a model and experimental embryology as an approach. We have proved that the Substantia nigra pars compacta plays a direct role as an intermediate target of the medial habenula axons. In the mutant mouse with lack of Gli2 function, this neural population is not specified and the medial habenular axons are misrouted rostrally towards the hypothalamus. In open neural tube explant cultures, we have transplanted ectopically this population derailing the host axons form their route towards the transplant. Therefore, we have proved that the Sustantia nigra pars compacta have a deep influence in the trajectory of the medial habenula axons. Work supported by ‘‘Ministerio de Economía y Competitividad’’ BFU2013-48230-P (FEDER Funds). Topic: Developmental Neurobiology


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THE MEDIAL HABENULA AXONS ARE GUIDED CAUDALLY BY A DCCNETRIN1 MECHANISM J. A. Moreno-Bravo1, V. Company2, A. Guerrero-Moreno2, C. Crespo-Quiles2, I. Juarez-Leal2, D. Echevarría2, E. Puelles2. 1 Institut de la Vision. UMR S 968 Inserm, UPMC, CNRS 7210, 17 Rue Moreau, 75012 Paris, France. 2 Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-CSIC, 03550 Sant Joan d’Alacant, Alicante, Spain.

The guidance of the growing axons is one of the main processes during the development of the central nervous system. In the last years, we have focus our research in the retroflex tract. This fascicle is originated in the habenula (dorsal prosomere 2). It is composed by to different group of axons, the lateral habenula axons that target mid-hindbrain nuclei and the medial habenula axons, in which we have concentrated, that target the interpeduncular nucleus (ventral rhombomere 1). In order to reach their target, they display a complex trajectory. They navigate ventrally along the dorsoventral axis, bend caudally in the proximity of the floor plate and grow caudally towards their target. We and others have elucidated partially the molecular mechanisms that control this complex process. Recently, we have demonstrated that the Sustantia nigra pars compacta plays a role as an intermediate target of the medial habenula axons. Therefore, this neural population is our principal candidate to control the caudal bending of these axons. Using the mouse as a model we have identify Netrin1 as the signal and Dcc as the receptor related for this process. The distribution of the dopaminergic neurons of the Substantia nigra generates a natural Netrin1 gradient, being more abundant caudally. In open neural tube explant cultures, we have demonstrated that netrin1 is sufficient to derail the medial habenula axons form their trajectory. The block of Dcc receptor in habenular neurons by antibodies avoid this deviation. The analysis of Dcc and Netrin1 lack of function in mouse models revealed strong alterations in the retroflex tract trajectory. Therefore, we have demonstrated that the caudal bending of the habenular axons due to the influence of the Substantia nigra pars compacta involve the Dcc-Netrin1 molecular mechanism. Work supported by ‘‘Ministerio de Economía y Competitividad’’ BFU2013-48230-P (FEDER Funds). Topic: Developmental Neurobiology


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GENERATION OF "MINI-BRAINS" FROM PLURIPOTENT STEM CELLS TO STUDY BRAIN DEVELOPMENT A. Bernabeu-Zornoza1, C. Palmer1, R. Coronel1, M. Lachgar1, L. Silva1, A. Zambrano1, I. Liste1. 1 . Unidad Funcional de Investigación de Enfermedades Crónicas (UFIEC). Instituto de Salud Carlos III (ISCIII), Majadahonda, Madrid, Spain.

Due to the complexity of the human brain, it is difficult to study many brain disorders in model organisms. The results that we can obtain nowadays are all made in monolayer cell cultures (2D), and, although highly valuable, those methods are devoid of a tridimensional component necessary for normal organ development. Therefore, the ability to model human brain development in vitro represents an important step in our study of developmental processes and neurological disorders. It has recently been described that pluripotent stem cells (Embryonic Stem Cells (ES) or induced Pluripotent Stem Cells (iPS)) in a suitable environment are capable of generating three-dimensional (3D) structures called "cerebral organoids or mini-brains". They recapitulate different stages of human cortical development, generating a variety of regional identities organized in discrete domains able to connect with each other. We are setting up a human and mouse ES cells three dimensional organoids culture system. The differentiation in organoids (3D) is being carried out according to the protocol recently published by Lancaster and Knoblich (2014) Nature Protocols 9(10):2329-40. It is based on a first phase of generation of floating embryoid bodies, followed by a second phase of transferring these embryoid bodies to plates for their neural induction and subsequent differentiation. The characterization of cultures and identification of different neural structures and phenotypes are being performed at cellular and molecular level by immunocytochemistry and quantitative-RT-PCR. Together, these studies would indicate that three-dimensional organoids can recapitulate human or mouse neurodevelopment and it can be useful to study the pathogenesis of neurological diseases.


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AMYLOID-β (1-40) AND (1-42) EFFECTS ON THE DIFFERENTIATION OF HUMAN NEURAL STEM CELLS A. Bernabeu-Zornoza1, R. Coronel1, M. Lachgar1, C. Palmer1, L. Silva1, C. Gil1, P. Velasco1, M. Calero1, E. Cano1, I. Liste1 1 . Unidad Funcional de Investigación de Enfermedades Crónicas (UFIEC). Instituto de Salud Carlos III (ISCIII), Majadahonda, Madrid, Spain.

Alzheimer’s disease (AD) is a neurodegenerative disorder characterized by memory loss and cognitive decline due to widespread loss of neurons and synaptic connections in the cortex, hippocampus, amygdala and basal forebrain. One of the main histopathologic features of AD is the formation and accumulation of amyloid plaques in the brain, formed by extracellular fibrillary aggregates of amyloid-β peptides (Aβ) generated by the enzymatic processing of amyloid precursor protein (APP). Aβ (1-40) and Aβ (1-42) peptides are the major isoforms found in these amyloid plaques. Although considered neurotoxic, Aβ peptides may play an important biological role in adult brain and during embryonic brain development. However, the physiological function of these Aβ peptides remain poorly understood. In order to comprehend more about the physiological role of these Aβ peptides, we studied the effects of both peptides at different concentrations, to see the effect they have on cell death, cell proliferation and cell fate specification in human neural stem cells (hNSCs; hNS1cell line) by immunocytochemistry and quantitative-RT-PCR. Our results showed that at high concentrations, the effects of both peptides are cytotoxic for these cells. In regard to cell proliferation, we observed a significant increase in proliferation of hNS1 cells after treatment with both peptides, particularly after treatment with Aβ (1-42) peptide. Finally, concerning cell fate specification, our data showed that treatment with Aβ (1-40) peptide significantly promotes neurogenesis, while treatment with Aβ (1-42) peptide induces glial differentiation in hNS1 cells. Together, our results suggest that Aβ peptides affect hNSCs biology and provide us more information about the physiological role of both peptides.


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AMYLOID PRECURSOR PROTEIN (APP) CONTROLS CELL FATE SPECIFICATION IN HUMAN NEURAL STEM CELLS

R. Coronel1, M. Lachgar1, A. Bernabeu-Zornoza1, C. Palmer1, L. Silva1, J. Hernández1, A. Fernández1, E. Cano1, A. Martínez-Serrano2, I. Liste1 1 . Instituto de Salud Carlos III (ISCIII), Majadahonda, Madrid, Spain. 2 . Centro de Biología Molecular “Severo Ochoa” (CBMSO-UAM), Madrid, Spain.

Amyloid precursor protein (APP) is a transmembrane protein widely expressed in the central nervous system. Numerous studies have focused on the role of APP in the pathophysiology of Alzheimer Disease (AD), and even Down Syndrome (DS), but its biological function remains unclear. It has been reported that APP is implicated in neural development, stimulating proliferation and glial differentiation of neural stem cells (NSCs), while other studies suggest an important effect in increasing neurogenesis in these cells. We have examined the endogenous APP expression in hNS1 cells, a model cell line of human NSCs, both under proliferation and throughout the differentiation period. Our results show elevated APP-immunoreactivity in hNS1 cells and, to investigate the potential function that APP plays in cell fate decisions of hNSCs, we transiently overexpressed human APP in hNS1 cells to analyze the intrinsic cellular effects. Our data indicate that high levels of APP induce early cell cycle exit and instructively directs hNS1 cell fate towards a glial phenotype, while decreasing neuronal differentiation. Since elevated APP levels also enhance AICD-immunoreactivity, these effects could be, in part, mediated by the APP/AICD system. The AICD domain can play a potential role in signal transduction by its molecular interaction with different target genes such as GSK3B, whose expression was also increased in APP overexpressing cells that, in turn, may contribute of promoting gliogenesis and inhibiting neurogenesis in NSCs. These data suggest an important action of APP in modulating hNSCs differentiation, probably in an AICD-GSK3β-dependent manner. To further verify our hypothesis, we inhibited the GSK3β effect on APP overexpressing cells and observed an important increase in neuronal differentiation of hNS1 cells, while gliogenesis decreased. These findings may contribute to future development of stem cell therapy strategies and GSK3β inhibitors for the diseased mammalian brains in which APP abundance is altered.


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CLONAL DISPERSION OF OLIGODENDROGLIA FROM INDIVIDUAL PROGENITORS M. Figueres-Oñate, N. Salvador, M. Sánchez-Villalón and L. López-Mascaraque Instituto Cajal-CSIC, NMCD

Cell lineages present in adult brains are generated by neural stem/progenitor cells (NPCs) located in the embryonic wall of the lateral ventricles. Moreover, adult brain preserves a neurogenic niche, located in the subventricular zone (SVZ) of the lateral ventricles, which continually provides the olfactory bulb with new interneurons. Additionally, adult NPCs also contribute to postnatal gliogenesis giving rise to astrocytes, oligodendrocytes and NG2 cells. Lineage tracing and progenitor potential determination is a hot topic in Neuroscience. However, oligodendroglial lineage is still poorly characterized specially at clonal level. The goal of this study was to perform an in vivo clonal analysis of the oligodendroglial lineage, generated by embryonic and postnatal single progenitors. In order to fully capture oligodendrocyte heterogeneity, embryonic/postnatal dorsal SVZ progenitors were targeted with the UbC-StarTrack clonal strategy. This method allows stochastically single NPCs labeling with unique color codes that are maintained in their complete cell progenies, regardless of their cell lineage or proliferative rate. Sibling cells were defined by the same composition of fluorophores, both in the same cell compartment and range of fluorescent intensity. To identify clonally-related oligodendrocytes, we performed in utero (from E12 onwards) or postnatal (P1) electroporations of nuclear and cytoplasmic UbC-StarTrack mixtures. Cell dispersion pattern as well as the number of cells comprising the same clone was different depending on the different targeted progenitors. Clonally-related sibling oligodendrocytes formed large adult clones rarely sparsely distributed, but located close each other in the corpus callosum or cortical layers. Thus, clonal analyses using the UbC-StarTrack strategy allowed decoding the neural heterogeneity of different cell lineages and their clonal relationships. To this respect, lineage potential of those ventricular progenitors is relevant to understand both the adult cell diversity and the NPCs nature. 1. Developmental Neurobiology 2. New methods and technologies


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EVALUATION OF SYNAPTOGENESIS IN MCT8 DEFICIENCY

A. García-Aldea 1, C. Grijota-Martínez 1, A. Montero-Pedrazuela 1, E. Rausell 2,4, A. Guadaño-Ferraz 1,3. 1 Instituto de Investigaciones Biomédicas Alberto Sols, Consejo Superior de Investigaciones Científicas (CSIC)Universidad Autónoma de Madrid (UAM), Madrid, Spain 2 School of Medicine, Dept Anatomy Histology & Neuroscience, Universidad Autónoma de Madrid, Spain 3 Center for Biomedical Research on Rare Diseases (Ciberer) Unit 708, Instituto de Salud Carlos III, Madrid, Spain. 4 Trastornos del Desarrollo y Maduración Neurológica (TRADESMA), IdiPaz-UAM, Madrid, Spain.

Allan-Herndon-Dudley syndrome (AHDS) is a rare disease in which a highly specific transmembrane transporter of thyroid hormones (T4 and T3), the monocarboxylate transmembrane transporter 8 (MCT8), is mutated. This syndrome is an X-linked inherited disorder characterized by congenital hypotonia that progresses to spasticity with severe psychomotor delay. Previous histopathological studies from our group show that AHDS patients present histological signs of brain hypothyroidism and suggest synaptogenesis defects. The aim of this study was to deep insight the synapsis abnormalities in AHDS. We analyzed the expression of synaptic scaffold proteins in the motor system of MCT8-deficient brain necropsy samples from two subjects, an 11-year-old boy and a 30th gestational week fetus, in comparison to healthy subjects of the same age. Samples from the motor cortex, basal ganglia and cerebellum were analyzed by immunohistochemistry using specific antibodies for a number of pre and postsynaptic proteins. Our results revealed altered expression of all the synaptic proteins analyzed in MCT8-deficient human brains, in all the examined regions, in comparison to control subjects. As there are no human hypothyroid brain samples available, the same proteins were analyzed in a rat model of adult-onset hypothyroidism (thyroidectomy at postnatal 75 days, sacrificed 20 days later) and no expression differences were found between hypothyroid and control animals. These results indicate a reduction in the density of synapsis rather than a decrease of the level of expression of the studied proteins due to the hypothyroid state. Overall our results suggest that the neural transmission is altered in patients with MCT8 deficiency. Topic: Developmental Neurobiology


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SCRATCH1 IN THE ADULT NEURAL STEM CELL

A. González-Iglesias 1, A. Domingo-Muelas 2, I. Fariñas 2, MA. Nieto1 1 . Instituto de Neurociencias, CSIC-UMH, San Juan de Alicante, Alicante, Spain 2 . Departamento de Biología Celular and ERI BiotecMed, Universidad de Valencia, Valencia, Spain

In mammals, adult neurogenesis is restricted to few niches in the central nervous system, being the subependymal zone (SEZ) the largest germinal region of the adult mammalian brain. In rodents, the neural stem cells (NSCs) that reside in this region give rise to neuroblasts that migrate and integrate in the olfactory bulb (OB), where they contribute to neural plasticity of olfactory information processing. A group of transcription factors that might regulate this process in mammals is the Scratch family, which belongs to the Snail superfamily of transcription factors and has been shown to promote neuronal differentiation in different species. We show that Scratch1 is expressed in the SEZ both in NSCs and in neuroblasts, although its transcripts present different subcellular localizations in these two cell types. In NSCs Scratch1 mRNA accumulates in the nucleus, probably due to alterations in splicing, which in turn affects mRNA export to the cytoplasm. In addition, ESCs and iPSCs reprogrammed from adult NSCs do not express Scratch1. This indicates that Scratch1 starts to be expressed when stem cell are committed to the neural lineage, although its mRNA is not available for translation until differentiation is induced. We propose that mRNA nuclear retention can operate as a mechanism to tightly control the timing on neural differentiation in the adult stem cell niche.


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IMPORTANCE OF FGF8 IN THE DEVELOPMENT OF MAMMILARY REGION TRACTS C. Crespo-Quiles, V. Company, A. Guerrero-Moreno, I. Juárez-Leal, E. Puelles and D. Echevarria. Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-CSIC, 03550 Sant Joan d’Alacant, Alicante, Spain.

Fibroblast growth factor 8 (Fgf8) plays pivotal roles for the early specification and differentiation of the developing CNS, due its morphogenetic activity and planar induction properties. This morphogen is secreted in a gradient manner from particular regions of the neural tube called secondary organizers. These are named from caudal to rostral: isthmic organizer (IsO), zona limitans intrathalamica (ZLI) and the anterior neural ridge (ANR). The latter organizer centre is placed at the most rostral part of the forebrain. Interestingly, Fgf8 is also expressed at the midline of the primordium of the hypothalamus at the murine embryonic stage E9.5. Thus, we have wondered the role of this morphogen during the specification and differentiation of the forebrain anlage and subsequently the axonal projection pathway network at telencephalic and hypothalamic levels. In this work, we have taken the advantage of the murine Fgf8 severe hypomorph mutants that contained very low levels of FGF8 in their organisms, to analyse by immunohistochemistry against Dcc and Calbindin, the axonal growth projection within this brain subdivision. The preliminary results show that the hypothalamic axonal tracts were not severely affected (mainly fornix, mammilothalamic and mammilotegmental tracts). However, telencephalic axonal projections that crossed the roof plate (corpus callosum, anterior commissure, hippocampal commissure) were severely affected, and other axonal decussation such the optic chiasm). This work was supported by ‘‘Ministerio de Economía y Competitividad’’ BFU2013-48230-P (FEDER Funds) Topic: Developmental Neurobiology


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FGF8 REQUIRES OF GAP JUNCTIONAL COMMUNICATION FOR ITS MORPHOGENETIC ACTIVITY DURING BRAIN DEVELOPMENT

C. Bosone1, A. Andreu2, S. Mancinelli3, C. Crespo-Quiles4, A. Guerrero-Moreno4, V. Company4, , I. Juarez-Leal, G.L. Liguori3, E. Puelles4 and D. Echevarria4 1 Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Dr. Bohr-Gasse 3, 1030 Vienna, Austria. 2 Sorbonne Universités, UPMC Univ Paris 06, UMR7622, CNRS, Institut de Biologie Paris Seine (IBPS), Paris, France 3 Institute of Genetics and Biophysics 'Adriano Buzzati-Traverso' (IGB), Consiglio Nazionale delle Ricerche (CNR), 80131 Naples, Italy. 4 Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-CSIC, 03550 Sant Joan d’Alacant, Alicante, Spain.

The compartmentation of central nervous system during embryonic development is due to the precise combination of transcription factors activated by morphogenic signaling from key regions, known as secondary organizers. One of the most characterized secondary organiser is the isthmic organizer (IsO). This center secretes molecules as the fibroblastic growth factor 8 (Fgf8) that has an anteroposterior planar inductive pattern. This fundamental paracrine effect communication through the secreted morphogen signal is surprisingly fast and may require the existence of other mechanisms involved in its long-distance spread. In our laboratory gap-junctions (GJs) role are being investigated as mediators of the inductive activity of Fgf8. Concretely, connexin-43 (Cx43), proteins that form GJs, show a restricted expression pattern at the first phases of development mouse brain (E9.5). The expression of the Cx43, seems like the activity territory of IsO so Fgf8, Cx43 and IsO activity may be related. Preliminary studies show that communication through GJs seems be necessary to the correct signaling of Fgf8. Using open neural tube culture explants (ONTCs), we blocked GJs by heptanol and GAP26 (specific blocker of Cx43). The results of these experiments demonstrate that IsO genes that Fgf8 signaling is rapidly affected. On the other hand, implantation of FGF8 soaked beads onto chicken neural tubes induced Cx43. These experiments support our hypothesis that signaling of Fgf8 are GJs activity-dependent and concretely Cx43-dependent. Work supported by ‘‘Ministerio de Economía y Competitividad’’ BFU2013-48230-P (FEDER Funds) y ‘Fondazione con il Sud’(2011-PDR-13) to G.L.L. y Development Travelling Fellowship (DEVTF-160711) to S.M. Topic: Developmental Neurobiology


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STUDY OF THE DEVELOPING INNER EAR OF THE SHARK SCYLIORHINUS CANICULA S. Pereira-Guldrís1, M. Candás2, I. Rodríguez-Moldes1 1 CIBUS-Faculty of Biology, University of Santiago de Compostela 2 Marine Biology Station of A Graña, University of Santiago de Compostela

The inner ear of vertebrates is a complex three-dimensional structure responsible for the detection of sound, balance and acceleration. The entire inner ear is formed from the otic placode, a thickness of the ectoderm adjacent to the hindbrain that invaginates or cavitates to form the otic vesicle and finally the developed inner ear. Studies about the inner ear development in cartilaginous fishes or Chondrichthyans, the most ancient radiation of jawed vertebrates, are crucial to gain knowledge about the origin and evolution of the inner ear. We have analyzed the development of the inner ear of the catshark Scyliorhinus canicula (a small shark recognized as an emerging model in evolutionary developmental studies) in embryos and juveniles scanned by microcomputer tomography (micro-CT), which rendered detailed 3D view of the morphological changes that happen during its development. These changes reveal interesting similarities between the formation of the inner ear in Chondrichthyans and other vertebrates as amphibians, birds and mammals, where the otic placode invaginates forming an otic cup, instead of cavitating as happens in bony fishes and reptiles. The analysis with micro-CT of samples at different stages allows to follow some relevant events of the inner ear development as the early formation of the statoacoustic ganglion at stage 25, the formation of the first semicircular canal at stage 27 and the achievement of the almost mature organization, with the main structures formed at stage 30. From this stage to hatching at stage 34, the size of the inner ear increases concurrently to the body growth. This study reveals the usefulness of micro-CT for studying the complex spatial arrangement of inner ear components in the three axes and for giving support to genoarchitectonic studies about this sense organ. Supported by Ministerio de Economía y Competitividad-FEDER (BFU2014-58631). Topics: 1. Developmental Neurobiology


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EFFECT OF DIFFERENT CANDIDATE GENES ON THE GENERATION OF DOPAMINERGIC NEURONS FROM HUMAN NEURAL STEM CELLS L. Silva1, C. Palmer1, M. Lachgar1, R. Coronel1, A. Bernabeu-Zornoza1, S. García-Lopez2, M. P. Pereira2, I. Liste1, A. Martínez-Serrano2 1 . Instituto de Salud Carlos III (ISCIII), Majadahonda, Madrid, Spain. 2 . Centro de Biología Molecular “Severo Ochoa” (CBMSO-UAM), Madrid, Spain.

The progressive degeneration of dopaminergic neurons (DN) is the defining characteristic of Parkinson's disease (PD), one of the most common neurodegenerative disorders that cause several motor symptoms. Current treatment options for PD are available to help relieve primary motor symptoms, but their long-term effectiveness is limited. For this reason, alternative treatment options are being sought in the form of stem cell-based therapies. Human Neural Stem Cells (hNSCs) could be potentially used in cell replacement therapy in PD. In previous studies we have shown that the overexpression of Bcl-XL in the immortalized cell line of ventral midbrain hVM1, potentiated the generation of DNs. However, Bcl-XL is not suitable for clinical use, and therefore, it is necessary to look for a safer alternative. In this work we have studied the effects of a group of genes, which have been selected as possible effectors of Bcl-XL, on the differentiation of hVM1 cells, especially in the generation of DNs. In particular the genes Bcl-XL, INSM1, NHLH1, GFRA1 and GADD45G have been analyzed and compared. Our results indicate that at least three of the genes studied enhanced the generation of DNs and thus could fulfill the role sought as substitutes for Bcl-XL in the biology of hVM1 cells.


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EARLY VASCULARIZATION PROCESS IN RELATION TO MESENCEPHALIC AND DIENCEPHALIC GENOARCHITECTURE IN THE MOUSE P. Melgarejo Otalora1,2, R. Martínez Marín1,2, L. Puelles1,2, J. L. Ferran1,2. 1. School of Medicine, University of Murcia, Murcia, Spain. 2. Institute of Biomedical Research of Murcia – IMIB, Virgen de la Arrixaca University Hospital. University of Murcia, Murcia, Spain.

The vascularization of the central nervous system (CNS) during embryonic development has hardly been studied under recent perspective and methods, and textbook versions remain based on researches made during the mid-20th century. Progress in our knowledge about molecular mechanisms of angiogenesis and vasculogenesis starts to register in studies published recently. We were curious about a potential selective topographic relationship of the patterns of penetrating blood vessels and associated perineural and periventricular vascular plexi with the differential molecular specification of distinct parts of the developing CNS, such as the neuromeric alar and basal domains of the diencephalon and mesencephalon contemplated in the prosomeric model. It never has been examined whether blood vessels respect the limits of different molecular domains, or react heterochronically with regard to them. The aim of this study accordingly was to analyze the topographic pattern adopted by different vessels (plexuses and perforant vessels) entering the diencephalon and the mesencephalon of mouse embryos, visualized within the prosomeric model paradigm. To achieve this, mouse embryo cryostat section series were hybridized between stages E8.5 and E12.5 with Kdr (a pan-endothelial marker blood vessel marker), comparing with the expression of regional diencephalic-mesencephalic markers (such as Dlx5, Pax3, Pax6, Shh, and Tcf7l2) in adjacent sections. The perineural vascular plexus shows a rough rostrocaudal gradient during its development, while perforating vessels and the periventricular vascular plexus show a neuromere-related heterochronic pattern. Notably, perforating vessels do not cross the boundaries between different molecular domains. The molecular mechanisms involved in such heterochronic development of the CNS vasculature should be clarified in the future. Supported by MEC/Feder grant BFU2014-57516P to LP and JLF, and 19904/GERM/15 Séneca Foundation contract to LP.. 1. Developmental Neurobiology


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ROLE OF CUX GENES IN RETINA DEVELOPMENT

P. Kaimakis1, L. Weiss2, M. Nieto2, P. Bovolenta1 1 . Centro de Biologia Molecular Severo Ochoa, CIBERER 2 . Centro National de Biotecnología

Cux1 and Cux2 (CUT homeobox 1 and 2) are members of the family of Cut transcription factors reported to contribute to different developmental events in the nervous system. For example, Cux2 controls the proliferation of neuronal progenitors of cortical layers II-III and IV, as well as those of the olfactory epithelium and spinal cord. Cux1 instead regulates callosal projection formation. Both genes have been involved in neuronal differentiation, including the control of dendritic branching and number of spines in neurons of the upper cortical layers. Both transcription factors have been associated with brain disorders of developmental origin, such as depression, bipolar disorder and autism spectrum disorders. Whether Cux genes have any role in retina development is however still unexplored. Here we have begun to address this question by determining the precise expression pattern dynamics of both genes during eye formation and by analyzing their loss of function. Our initial results show that Cux1 is expressed in the retinal layer at optic cup stages and both Cux1 and Cux2 localize to a subpopulation of retinal ganglion cells (RGCs) and to cells of the neuroblastic layer. Analysis of the retinal phenotype of Cux1-/- and Cux2-/- mice reveal similar retinal defects, characterized by alterations in the organization and number of the RGCs. Furthermore, the inner plexiform layer (IPL) is reduced in thickness and the amacrine cell layer is affected, suggesting the possibility that in the retina Cux genes regulate both the number of neurons and the growth of their processes, similarly as in the cortex. Ongoing studies will elucidate these possibilities.


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STUDY OF INITIAL VASCULARIZATION IN RELATION TO HYPOTHALAMIC AND TELENCEPHALIC GENOARCHITECTURE IN THE MOUSE. R. Martínez Marín1,2, P. Melgarejo Otalora1,2, J. L. Ferran1,2, L. Puelles1,2. 1. School of Medicine, University of Murcia, Murcia, Spain. 2. Institute of Biomedical Research of Murcia – IMIB, Virgen de la Arrixaca University Hospital. University of Murcia, Murcia, Spain.

The prosomeric model allows studying brain regionalization using a well-supported paradigm. Various anatomical relations can be explored causally from a topological point of view within a model of cerebral morphogenesis shared in vertebrates. We address here differential vascularization patterns in relation to prosomeric brain subdivisions, an aspect that has not been examined previously. Classical work on vascularization underlined an early perineural vascular plexus that generates perforating vessels, which reportedly penetrate the neural parenchyma in a ventrodorsal gradient. The perforating vessels produce a periventricular vascular plexus and other collateral branches. The aim of the present study was to investigate in mice embryos whether early vascularization is regionally sensitive to the differential molecular specification of distinct sectors of the rostral forebrain (hypothalamus and telencephalon), in the form of region-selective or heterochronic aspects of the perforating vessels or perineural and periventricular plexi. To this aim we performed “in situ” hybridizations in serial sections of embryonic mice brains between E8.5 and E12.5, combining a pan-endothelial blood-vessel marker (Kdr) with regional neural markers such as, Dlx5, Pax6 and Shh Tcf7l2, whose distinct expression domains in the rostral forebrain are well known, characterizing given subregions. The results indicate that the first perineural vascular plexus emerges at E8.5. Early perforating vessels appear in this region at E9.5, and soon generate the periventricular plexus branches. There is a remarkable heterochronic pattern of perforating and branching vessels in hypothalamic and telencephalic regions, which negates the existence of any ventrodorsal o rostrocaudal gradient. The data suggest that the order of vascular invasion is correlated with the heterochronic advance of neurogenesis in the molecularly different neural territories. Supported by MEC/Feder grant BFU2014-57516P to LP and JLF and 19904/GERM/15 SÉNECA Foundation (Community of Murcia) contract to LP. 1. Developmental Neurobiology


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ON-SITE GENERATION OF THE ADULT NEURAL STEM CELL POPULATION IN THE POSTNATAL DENTATE GYRUS

O. Pastor1,2, J.R.Pineda1, A. Urbach3, J. M. Encinas1,2,4. 1 Achucarro Basque Center for Neuroscience, Leioa, Spain. 2 University of the Basque Country (UPV/EHU), Leioa, Spain. 3 Universitätsklinikum Jena, Department of Neurology, Jena, Germany 4 Ikerbasque, The Basque Foundation for Science, Bilbao, Spain.

The population of hippocampal neural stem cells (NSCs) decreases markedly with age, as depletion is faster than self-renewal. As the relative proportion of activated NSCs remains constant over time, the neurogenic output throughout adulthood is mainly determined by the size of the initial pool of NSCs. However, how and when the NSCs get established in the subgranular zone (SGZ) of the dentate gyrus (DG) remains mostly unknown. Using Nestin-GFP transgenic mice, in which NSCs can be readily visualized and analyzed, we observed that adult-like radial NSCs (rNSCs) can be identified, as nestin and GFAP-expressing cells with radial morphology and profuse arborization in the molecular layer, at postnatal day 7 (P7), but not earlier. From then on, the rNSC population increases in size reaching a maximum at P14-21. Interestingly, using the Lysophosphatidic Acid Receptor 1-enhanced Green Fluorescent Protein (LPAR1-eGFP) transgenic mice, recently shown to selectively label NSCs in the hippocampus, we found that the expression of LPAR1 starts in the NSC population by P7, suggesting a possible functional role of LPAR1 in the establishment of the adult rNSC population in the postnatal dentate gyrus. Furthermore, in the postnatal cyclin D2 knock-out mice (D2KO) the population of NSCs fails to expand from P7 to 14, resulting in an almost absent population of adult rNSCs and neurogenesis at P28. These results put together suggest that the adult rNSC population is established in the postnatal dentate gyrus within a discrete critical period and therefore adult hippocampal neurogenesis cannot be considered a mere continuation of hippocampal development. In addition, we predict that any alterations affecting NSCs around P7 in the DG will strongly alter the adult neurogenic output. Topics: Developmental Neurobiology


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SEROTONERGIC PROJECTIONS GOVERN POSTNATAL NEUROBLAST MIGRATION D. García-González1*, K. Khodosevich1,2*, Y. Watanabe1, A. Rollenhagen3, J. Lübke3,4 and H. Monyer1 1 Heidelberg University and German Cancer Research Center (DKFZ), Heidelberg, Germany 2 University of Copenhagen, Copenhagen, Denmark 3 Research Centre Jülich GmbH, Jülich, Germany 4 RWTH/University Hospital Aachen, Germany *Equal contribution

In many vertebrates, postnatally generated neurons often migrate long distances to reach their final destination where they help shape local circuit activity. Concerted action of extrinsic stimuli is required to regulate long-distance migration. Some migratory principles are evolutionarily conserved, whereas others are species- and cell type-specific. Here we identified a serotonergic mechanism that governs migration of postnatally-generated neurons in the mouse brain. Serotonergic axons originating from the raphe nuclei exhibit a conspicuous alignment with subventricular zone-derived neuroblasts. Optogenetic axonal activation provides functional evidence for serotonergic modulation of neuroblast migration. Furthermore, we show that the underlying mechanism involves serotonin receptor 3A (5HT3A)mediated calcium influx. Thus, 5HT3A receptor deletion in neuroblasts impaired speed and directionality of migration and abolished calcium spikes. We propose that serotonergic modulation of postnatally-generated neuroblast migration is evolutionarily conserved as indicated by the presence of serotonergic axons in migratory paths in other vertebrates. Topic: Developmental Neurobiology


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USP8 DEUBIQUITINATES FUNCTIONS

TRKB


AND

MODULATES

TRKB-BDNF

Martín-Rodríguez, C.1,2; Song, M.3; Anta, B.1; Lee, F.S. 4,5; and Arévalo, J.C.1,2 1 Department of Cell Biology and Pathology, Instituto de Neurociencias de Castilla y León (INCyL), University of Salamanca, Salamanca 37007, Spain. 2 Institute of Biomedical Research of Salamanca (IBSAL), Salamanca 37007, Spain. 3 Synaptic Circuit Plasticity Laboratory, Department of Structure & Function of Neural Network, Korea Brain Research Institute, 61 Cheomdan-ro, Dong-gu, Daegu, 701-300, Korea. 4 Department of Psychiatry, Weill Medical College of Cornell University, 1300 York Avenue, New York, NY 10065, USA. 5 Department of Pharmacology, Weill Medical College of Cornell University, 1300 York Avenue, New York, NY 10065, USA.

Ubiquitination of the TrkA neurotrophin receptor is a well-recognized mechanism that plays an important role in nerve growth factor (NGF) functions. Although TrkB ubiquitination has also been reported, the molecular machinery involved in the ubiquitination/deubiquitination of the receptor in response to brain derived neurotrophic factor (BDNF) is completely unknown. Here we describe the identification of the ubiquitin-specific protease 8 (USP8), as a deubiquitinase for TrkB. TrkB and USP8 interact in cultured cortical neurons through the c-terminus of TrkB and the MIT domain of USP8. Overexpression of USP8 increases the total amount of TrkB protein and its deubiquitinating activity is required for this effect. Indeed, in vitro deubiquitination assays show that USP8 deubiquitinates the receptor and knock-down of USP8 protein in neurons increases TrkB ubiquitination in response to BDNF. In addition, USP8 depletion impairs TrkB endocytosis and BDNF-mediated signaling, resulting in a reduced dendritic arborization of hippocampal granule cells in vivo. Altogether, these data indicate that the modulation of TrkB ubiquitination by USP8 regulates the trafficking and the signaling of the receptor and, consequently, TrkB-BDNF functions, highlighting the relevance of TrkB ubiquitination. Topic: Developmental Neurobiology


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NOVEL CA1-CA1 COMMISSURAL PROJECTION PATHWAY

Authors: Noelia S. de Leon Reyes1, María J. Galazo2, Marta Nieto1. 1 Centro Nacional de Biotecnología (CNB-CSIC), Campus de Cantoblanco, Darwin 3, 28049, Madrid, Spain 2 Department of Stem Cell and Regenerative Biology, Center for Brain Science, and Harvard Stem Cell Institute, Harvard University, Cambridge, MA 02138, USA

Untangling hippocampal connectivity has implications for our understanding of learning and memory, as well as of diseases such as epilepsy or neurodegenerative disorders. Even though there’s a relatively good knowledge of the entorhinal–hippocampal network, many aspects of the interhemispheric connectivity of the hippocampus remain unknown. While two major commissural projections have been well characterized in rodents (hilar cells projecting to the contralateral molecular layer of the dentate gyrus, and CA3 pyramidal cells connecting with contralateral CA3 and CA1 neurons) a possible CA1 to CA1 commissural pathway has been only indirectly suggested by few studies. Here we developed stereotaxic injections of the retrograde tracer CTB in dorsal and anterior hippocampal commissure of C57BL6 mice at postnatal day 5 (P5), P14 and P30 in order to identify commissural CA1 neurons at these stages. We further developed site-directed in utero electroporation based on a third-electrode system, to specifically label CA1 neurons and their projections with GFP. Immunohistochemical analysis allowed us to identify the existence and specific location of commissural branches originated from ipsilateral CA1 and abundant GFP branches in the contralateral field of the CA1 electroporated area. These branches were specifically located in the stratum oriens and stratum radiatum of the homotopic electroporated area. Abundant labeling of CTB+ neurons was detectable in CA1 at P5, P14 and P30, also demonstrating the existence of inter-hemispheric homotopic projections from CA1. Altogether these data reports a novel CA1-CA1 commissural projection pathway that might be maintained in the adult circuit. Future experiments based on optogenetics will help us to elucidate this and the physiological function of this commissural connection.


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NETRIN1/DCC SIGNALING PROMOTES NEURONAL MIGRATION OF SELECTIVE POPULATIONS FORMING THE INTERPEDUNCULAR NUCLEUS

A. Alonso1, N. Morales-Delgado1, R. Corral-San Miguel1, F. Marín1, B. Andrés2, L. Puelles1, G. López-Bendito2, P. Aroca1 1 . Facultad de Medicina, Universidad de Murcia e Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca. Murcia. España 2 . Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas (UMH-CSIC), San Joan d´Alacant. Alicante. España.

Background: During development, postmitotic neurons often migrate to their corresponding destination before undergoing final differentiation and establishing brain connections. We have previously demonstrated that the interpeduncular nucleus (IP) is formed by various neuronal populations identified by the expression of specific transcription factors (Otp, Otx2, Pax7 and Nkx6.1). These neurons follow independent tangential migratory pathways to reach its final destination in the IP. However, the molecular pathway that regulate these migration processes remain unknown. Netrin1/DCC function as chemoattractant process in axonal and neuronal guidance during brain developing. Objective and Methodology: Our aim is to evaluate if Netrin1-DCC-mediated attraction guides the migration of some neuronal populations forming the IP. We have first analyzed the expression of the Netrin-1 receptor DCC in the IP. Secondly, we have analyzed the development of the IP in the mice deficient in DCC production (DCC-/-). In these mice, we have evaluated the migration to the IP nucleus of some neuronal populations, evidenced by the expression of the above transcription factors. The analysis was performed in Wt and the DCC-/- mice, using single in situ hybridization (ISH) or double ISH-immunohistochemistry labeling. Results and Conclusions: We found that the dorsoventral migration of the Pax7-positive neurons to the IP are impeded in DCC-/- mice. However, lateromedial migration of Otx2-positive neurons to the IP is not affected. Together with our previous data, these results establish a requirement for netrin 1 in the migration of some selective neuronal populations forming the IP. Supported by Spanish MICINN BFU2006-15330-C02-01/BFU and NINECO SAF2014-59347-C2-1R grants to P. Aroca; Spanish MINECO grant BFU2014-57516-P and Regional Seneca Foundation grant 19904/GERM/15 to L. Puelles; and Spanish MINECO grant BFU2015-64432-R to G. López Bendito. Topic: 1. Developmental Neurobiology


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INSIGHTS OF PERICYTE ROLE IN NEUROVASCULAR NICHE DURING ANGIOGENESIS IN CHICK EMBRYOS F. Cabello-Torres1, A. Pombero2, R. Garcia-Lopez2, S. Martínez1,3 1 . Instituto de Neurociencias, UMH-CSIC, Alicante (Spain) 2 . IMIB-Arrixaca, Universidad de Murcia, Murcia (Spain) 3 . Centro de Investigación Biomédica En Red en Salud Mental (CIBERSAM)

During Central Nervous System (CNS) development, neural cells and non-neural cells, including vascular cells and microglia, coexist in the neurovascular niche. Anatomical complexity of these neurovascular niches during late development stages at specific CNS regions, suggests an important role of non-neural derived cells in functional maturation of brain. After neurulation cerebral parenchyma is generated by proliferation of neural progenitors, while blood vessels begin to prune inside the neural tissue from the pial surface. The onset of angiogenesis is someway controlled by pericytes, a perivascular cell type that covers endothelium and takes part of blood brain barrier structure, establishing a mutual interaction with brain precursors which suggest to play a role in maturation of neural cells. The role of this cell population in neurovascular niche is still unclear and requires experimental analysis. Using chick embryo as animal model, we have attempted to generate a brain with pericyte-depleted blood vessels by ablating the neural crest in pre-migratory stages. In the brain, neural crest derived pericytes are located exclusively in forebrain and midbrain regions, and could not be replaced by mesodermal-derived pericytes. Functional and anatomical analysis of brain microvessels in experimental and wild-type embryos were made using immunohistochemistry and RNA in situ hybridization. Our results show differences of pericyte coverage and anatomical maturation of parenchymal microvessels between experimental and wild-type embryos. We have also characterized the vascular plexus development during different stages of gestation, focusing in maturation of the vascular connections. Further studies on the development and maturation of neural cells in experimental samples will allow to understand the functional importance of neural crest derived pericytes in neurovascular and neural development. Topic: 1 Developmental Neurobiology


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TOWARDS A MODEL OF SIX PALLIAL DIVISIONS? A. Abellán , E. Desfilis, L. Medina Facultat de Medicina. Universitat de Lleida, IRBLleida, Lleida, Spain

The combinatorial expression patterns of regulatory genes, studied under the scope of the evolutionary developmental biology, have become crucial for identifying homologous pallial divisions and understanding their evolution. This approach led to a change of paradigm, moving to a tetrapartite model, with newly defined ventral and lateral pallial sectors, which were suggested to produce different parts of the claustrum, pallial amygdala and piriform cortex. This model was recently updated and, based on genetic fate mappings, it now appears that only the ventral pallium but not the lateral pallium - produces cells for the pallial amygdala. However, the tetrapartite model is currently facing problems for explaining the origin of pallial structures at the caudal pole of the telencephalic hemispheres (a region often ignored in gene expression studies). These problems also interfere with attempts for trying to find homologues of that caudal region in the pallium of nonmammals. In order to solve these problems, we studied the expression of a battery of developmental regulatory genes in the embryonic brain of mouse and chicken using in situ hybridization, paying special attention to the caudal levels. Our results helped to identify two novel caudal pallial sectors, different from the medial, dorsal, lateral, and ventral pallium. The new sectors are a dorsolateral caudal pallium (expressing Emx1 and Jag1, but not markers defining other pallial sectors as Lef1, Dbx1, COUP-TF2, Sfrp2, ER81, and FoxP1), related to the lateral entorhinal cortex, and a ventrocaudal pallium (expressing Emx1, Lhx9, COUP-TF2, and Zic2, but not Lef1, Dbx1, Sfrp2, ER81, and FoxP1), producing the posterior pole of the pallial amygdala. The newly defined sectors may provide a useful framework to test questions on their evolution and their derivatives, and may contribute to understand the expansion of the entorhinal cortex and the pallial amygdala in some mammals, such as primates. Sponsor: MINECO and FEDER, grant no. BFU2015-68537-R Topic: 1. Developmental Neurobiology


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ROLE OF P75NTR IN BASAL FOREBRAIN CHOLINERGIC NEURON CELL DEATH DURING DEVELOPMENT. R. Comaposada Baró 1, M. Vilar 1 1 . Institut de Biomedicina de València,CSIC, València, Spain.

The receptor of neurotrophin p75 (p75NTR) is expressed during development in central and peripheral nervous system. However, basal forebrain cholinergic neurons (BFCN) are the unique population of neurons that express p75NTR during adulthood, playing a key role in the maintenance of these neurons. Basal forebrain is divided into the medial septum nucleus, the horizontal and diagonal bands of Broca and the nucleus basalis magnocellularis, the first one innervates to the hippocampus and the last one to the cerebral cortex (beyond other structures) modulating superior cognitive processes as learning and memory. Moreover, it is widely accepted that these neurons are the first to degenerate in cognitive impairment as Alzheimer’s Disease (AD). The paper that p75NTR has during postnatal development has been extensively studied but always with contradictory conclusions. Due to the importance of these cholinergic neurons we want to get a deeper insight, for this, the cholinergic neurons of the area of interest was counted at different ages (P0, P6, P10 and P16) and compared to p75NTRexonIII mice. Topic: 1. Developmental Neurobiology


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TANGENTIAL MIGRATION FROM THE ALAR DIENCEPHALON TO THE HYPOTHALAMIC PARAVENTRICULAR NUCLEUS Alonso A.1, Puelles L1 and Trujillo C.M.2 1. Faculty of Medicine. University of Murcia and IMIB-Arrixaca. Murcia 2. Faculty of Biology. University of La Laguna. S/C de Tenerife. Islas Canarias.

The prethalamic eminence (PThE) and the hypothalamic paraventricular nucleus (Pa) are glutamatergic territories (Puelles et al., 2012). Both territories share the expression of Tbr1 and VGlut2 (selective marker of glutamatergic neurons). In previous work we demonstrated that PThE is a source of glutamatergic neurons that migrate tangentially into the telencephalic commissural plate and the preoptic area. Some migrating prethalamic neurons seemed to invade the alar hypothalamus. In order to examine whether the avian PThE is a source of migratory neurons targeting the alar hypothalamus, we performed homotopic and homochronic PThE transplants between quail and chick embryos, at early developmental stages HH10/HH11, and we sacrificed the chimeras at different intermediate developmental stages, mapping the grafted quail tissue by means of QCPN immunochemistry. Some chimeric brains were processed by in situ hybridization, using mRNA probes to detect Tbr1 and Otp genes (the latter is a characteristic marker of the Pa). The analysis of chimeric brains in which the presumptive PThE territory was grafted demonstrated that numerous neurons migrate from the PThE to its rostral neighbour, the hypothalamic Pa territory. Some of these neurons follow a pathway parallel to the ventricle and populate the hypothalamus immediately rostral to the PThE, while others migrate more superficially and pass around the cerebral peduncle just before it emerges from the telencephalon. We conclude that a subpopulation of glutamatergic neurons of the hypothalamic paraventricular nucleus originates in the PThE and secondarily populates the paraventricular rostral alar hypothalamus. Supported by MEC/Feder grant BFU2014-57516P and Séneca Foundation contract 19904/GERM/15 to LP


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USING SINGLE NEURON RNA-SEQ TO STUDY THE ROLE OF THE TRANSCRIPTION FACTOR IKAROS IN STRIATAL DEVELOPMENT

P. Sanders 1,2,3,4,5, G. Bombau 1,2,3,4,5, M. Galofre Centelles 1,2,3,4,5, A. Guillaumet-Adkins 6,7, G. Rodriguez-Esteban 6,7, H. Heyn 6,7, J. M. Canals1,2,3,4,5. 1 University of Barcelona, Barcelona, Cataluña, Spain. 2 Production and Validation Center of Advanced Therapies (Creatio), University of Barcelona, Barcelona, Cataluña, Spain. 3 Neuroscience Institute, University of Barcelona, Barcelona, Cataluña, Spain. 4 August Pi i Sunyer Biomedical Research Institute (IDIBAPS), Barcelona, Cataluña, Spain. 5 Networked Biomedical Research Centre for Neurodegenerative Disorders (CIBERNED), Spain. 6 Centro Nacional de Análisis Genómico (CNAG-CRG) - Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology (BIST), Barcelona, Cataluña, Spain. 7 Universitat Pompeu Fabra (UPF), Barcelona, Cataluña, Spain.

Ikaros is a zinc finger transcription factor that is essential for the development of a subset of striatopallidal medium spiny neurons (MSNs), the cell type that is primarily affected in Huntington’s Disease (HD). However, the specific role of Ikaros in MSN development remains unknown. To investigate this we induced Ikaros expression during the in vitro differentiation of human embryonic stem cells to forebrain neurons using a lentiviral inducible expression system. During this induction window, days in vitro (DIV) 17 to 21 of the differentiation protocol, the majority of cells are at the immature neuron stage. To identify the effects of induced Ikaros expression on gene expression at the single cell level we performed massively parallel RNA single-cell sequencing (MARS-SEQ) on both control neurons and neurons expressing different levels of Ikaros. MARS-SEQ was performed at DIV 21 and 38 to investigate the direct effects and the long term consequences of Ikaros expression respectively. Initial unbiased analysis of expression data from more than 1200 individual neurons at DIV 21, using principal component analysis and t-distributed stochastic neighbor embedding, reveals that Ikaros expressing neurons have a clearly distinct gene expression profile compared to the control neurons. Both up- and down-regulated putative marker genes for the Ikaros expressing population have been identified, with the functions of these marker genes suggesting the cellular processes that are regulated by Ikaros. Work is currently underway to verify these observations. With further analysis of the substantial single neuron transcriptome data sets that we have generated we anticipate that we will establish the specific role of Ikaros during striatal development. Furthermore we expect to identify novel markers for the neuronal sub-types that are present in our cultures, and to improve the efficiency of MSN in vitro differentiation for cell therapy treatment of HD. This work has been supported by Ministerio de Economía y Competitividad, Spain; ISCIIISubdirección General de Evaluación and European Regional Development Fund (ERDF) [RETICS and CIBERNED]; Catalonia Trade and Investment, Generalitat de Catalunya and ERDF [ADVANCE(CAT)], Spain; and CHDI Foundation Inc., USA.


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Atg4b IS NECESSARY FOR PHYSICAL EXERCISE ADAPTATIONS IN BRAIN H. Codina-Martínez, C. Díez-Planelles, AF. Fernández, M. Fernández-Sanjurjo, S. Díez-Robles, S. García-Higarza, E. Iglesias-Gutiérrez, B. Fernández-García, C. Tomás-Zapico. 1. Facultad de Medicina y Ciencias de la Salud. Universidad de Oviedo, Oviedo. 2. Instituto Universitario de Oncología (IUOPA). Universidad de Oviedo, Oviedo.

Molecular mechanisms underlying exercise-induced adaptations in brain are not well known and even whether the type, intensity or duration of the exercise have different effects over this process. Since exercise is considered as an autophagy inductor, we used the atg4b-/- mouse model, with a systemic reduction of autophagy, to determine these issues. Therefore, we considered two types of exercise, endurance and resistance, and two exercise periods, 2 and 12 weeks, and explored their effects on different brain areas. First, we analyzed adult neurogenesis in hippocampus by means of doublecortin (DCX) cell quantification. Our results indicated that exercise was able to increase neurogenesis in Wt mice, independently of type and duration. Interestingly, atg4b-/- mice did not show differences in DCX+ cells. Moreover, we were not able to detect DCX+ cells in any of these mice in the 12-week training, when they were 6 months old. We next explored basal autophagy levels and we did not find changes in hippocampus, striatum and cerebellum in our model. However, basal autophagy was increased in cerebral cortex of both Wt and atg4b-/- after exercise. Nonetheless, while Wt mice showed basal autophagy enhancement after 12 weeks of exercise, independently of the type, endurance atg4b-/- mice increased their basal levels after 2 weeks of exercise. Finally, since autophagy is known to be required during synaptogenesis and to participate in synaptic function, we further explored the effects of autophagy impairment on the chaperone proteins CSP and synuclein. Our results show that both were not affected by exercise in Wt mice, but they were decreased in atg4b-/- cerebellum, independently of the type and duration. In summary, our results reinforce autophagy role in brain health favoring important processes such as adult neurogenesis and synaptic protein recycling at the synapse, and highlight the benefits that exercise can provide to cellular homeostasis. Topic: 10. Others


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ROLE OF PRIMARY CILIA IN THE CONTROL OF NEURAL PROGENITOR PROLIFERATION AND FATE IN THE MOUSE FOREBRAIN A. Andreu 1, A. Karam 1, I. Anselme 1, M. Catala 1, C. Laclef 2, S. Schneider-Maunoury 1 1 . Institut de Biologie Paris Seine – Université Pierre et Marie Curie, Paris, France. 2 . Institut du Fer à Moulin, Paris, France.

Primary cilia are microtubular organelles with sensory functions. In vertebrates, they are present in almost every cell during development and are involved in the transduction of several signalling pathways such as the Hedgehog (Hh),Wnt, Pdgfa and Notch pathways. Ciliary defects lead to human diseases called ciliopathies. We focus on the Ftm/Rpgrip1l gene, which encodes a ciliary protein and is involved in severe ciliopathies with associated brain abnormalities, Meckel and Joubert syndromes. The Ftm KO mouse line is a good model to study the physiopathology of this human condition. Using this line, our previous work demonstrated a major function of primary cilia in early telencephalic patterning, olfactory bulb morphogenesis and corpus callosum formation. Ftm KO foetuses at the end of gestation also display a severely disorganized diencephalon and hypothalamus. In order to uncover the developmental causes of these defects, we analysed their formation and patterning in the Ftm KO mouse forebrain. By in situ hybridization with molecular markers of the different diencephalic and hypothalamic subdivisons at early stages, we observed a striking defect in dorso-ventral patterning of the forebrain. We found that the pretectum, thalamus and prethalamus were expandede ventrally. In contrast, the most ventral part of the forebrain was strongly reduced or absent. Neurogenesis was also affected in the diencephalon of Ftm mutants, with a reduced number of neurons and an increased proliferation of progenitors. We are currently investigating the molecular mechanisms leading to these defects,,Our current data indicate a strong and early downregulation of the Hh pathway in the ventral forebrain of Ftm embryos..Our results thus uncover crucial functions for primary cilia in the formation of ventral forebrain structures, and point to a possible involvement of ciliopathy gene mutations in holoprosencephaly, a human condition often associated with defects in the Hedgehog (Hh) signalling pathway.


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THE TRANSCRIPTION FACTOR GLASS LINKS EYE FIELD SPECIFICATION WITH PHOTORECEPTOR DIFFERENTIATION IN DROSOPHILA F. Javier Bernardo-Garcia 1, Cornelia Fritsch 1, Tim-Henning Humberg 1, Simon G. Sprecher 1 1 Department of Biology, University of Fribourg, Fribourg 1700, Switzerland

Eye development depends on a group of evolutionarily conserved transcription factors, termed the "Retinal Determination Network" (RDN). However, little is known about the molecular mechanism by which they coordinate eye formation. Particularly, how do RDN genes instruct photoreceptor differentiation? Our work shows that a key step in this process is regulated by the zinc finger transcription factor Glass, a direct target of the RDN member Sine oculis. While previous literature has shown that Glass is primarily expressed in all types of Drosophila photoreceptors, its role was incompletely understood because it was believed that glass mutant photoreceptor precursors died during metamorphosis. Contrary to former studies, we demonstrate that these cells survive development, but fail to mature as functional photoreceptors. Importantly, we have found that Glass is completely required for rhabdomere formation and for the expression of virtually all phototransduction proteins. Another step during photoreceptor development is regulated by the homeodomain transcription factor Hazy. Notably, we have found that Glass directly activates hazy expression, and inducing Hazy in the retina partly rescues the glass mutant phenotype. Also, we show that Glass and Hazy act synergistically and are sufficient to ectopically induce most phototransduction proteins when misexpressed in the brain. We have identified additional direct targets of Glass by using the TaDa technique. Taken together, our results show a transcriptional link between eye field specification and photoreceptor cell differentiation in Drosophila and place Glass at a key position in this developmental process. Topic: 1) Developmental Neurobiology


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Poster Topic s

2 .

Neural Excitability, Synapses and Glia: Cellular Mechanisms


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SNARE MACHINERY INVOLVED IN AMPA AND GABAA RECEPTOR TRAFFICKING S. Jurado 1,2, J.J. Ramírez Franco 1, F.J. Muñoz Cuevas1 1 . University of Maryland School of Medicine, Baltimore, USA 2 . Current address: Instituto de Neurociencias, San Juan de Alicante, Alicante, Spain

Together AMPA and GABAA receptors (AMPARs, GABAARs) mediate most of fast excitatory and inhibitory synaptic transmission, respectively. Their constitutive and activity-dependent trafficking mediate basal synaptic strength and plasticity, however the precise sorting machinery underlying their recycling pathways remains unclear. Furthermore, it is currently unknown whether AMPARs and GABAARs are sorted into different vesicular compartments or whether both receptors are jointly stored and exocytosed to then reach their specific synaptic microdomains. Increasing evidence has suggested important roles for the SNARE protein family in regulating the vesicular trafficking of AMPA and GABAA receptors. To address how these receptors are sorted within dendritic compartments, we sought to identify the exocytic molecules underlying their insertion into the plasma membrane. Here, we used a combination of in vivo viral-mediated knockdown and electrophysiology to analyze the effect of disrupting endogenous SNARE proteins on the constitutive insertion of AMPARs and GABAARs. Using this approach, we also examined activity-dependent AMPARs exocytosis during homeostatic plasticity and long-term synaptic potentiation (LTP), a prominent form of Hebbian plasticity. Our data indicate the molecular composition of the SNARE complex underlying constitutive insertion of AMPARs differs from the mechanism involved in regulated exocytosis. Whereas AMPARs exocytosis during LTP requires transmembrane t-SNARE syntaxin-3, constitutive trafficking and homeostatic plasticity seem to be unaffected by the lack of this syntaxin isoform but sensitive to the loss of syntaxin-4. Interestingly, GABAARs trafficking may engage different SNARE molecules during their constitutive recycling since none of the SNARE proteins that affected AMPARs altered GABAAR-mediated transmission. Our results suggest that excitatory and inhibitory neurotransmitter receptors are sorted into different vesicles which are regulated by different exocytosis mechanisms during basal transmission and synaptic plasticity.


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PYK2 MODULATES HIPPOCAMPAL EXCITATORY SYNAPSES AND MEDIATES HUNTINGTON'S DISEASE COGNITIVE DEFICITS

A Giralt1,2,3, V Brito4,5,6,7, Q Chevy1,2,3,, C Simonnet1,2,3, Y Otsu1,2,3, B de Pins1,2,3, J Alberch4,5,6,7, S Ginés4,5,6,7, JC Poncer1,2,3, JA Girault1,2,3* 1 Inserm UMR-S 839, Paris, France 2 Université Pierre & Marie Curie, Sorbonne Universités, Paris, France 3 Institut du Fer a Moulin, Paris, France. 4 Departament de Biomedicina, Facultat de Medicina, Universitat de Barcelona, Barcelona, Spain. 5 Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain. 6 Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain. 7 Institut de Neurociències. Universitat de Barcelona, Barcelona, Spain

The structure and function of spines and excitatory synapses are under the dynamic control of multiple signaling networks. Although tyrosine phosphorylation is involved, its regulation and importance are not well understood. Here we study the role of Pyk2, a non-receptor calciumdependent protein-tyrosine kinase highly expressed in the hippocampus. Hippocampal-related learning and CA1 long-term potentiation is severely impaired in Pyk2-deficient mice, in association with alterations of NMDA receptors, PSD-95, and dendritic spines. In cultured hippocampal neurons Pyk2 plays autophosphorylation-dependent and -independent roles in PSD-95 enrichment and spines density. Pyk2 levels are decreased in the hippocampus of Huntington's disease patients and of the R6/1 mouse model of the disease. Normalizing Pyk2 levels in the hippocampus of R6/1 mice rescues memory deficits, spines pathology, and PSD-95 localization. Our results reveal a critical role of Pyk2 in spine structure and synaptic function, and suggest that its deficit reversibly contributes to Huntington’s disease cognitive impairments. Topic: Select the topic which best fits to your paper. 1. Neuronal excitability, synapses and glia: cellular mechanisms


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ALTERED SYNAPTIC GAIN IN AMYGDALA CIRCUITS AFTER Grik4 OVER-EXPRESSION Vineet.Arora, M. Isabel Aller and Juan Lerma Instituto de Neurociencias, CSIC-UMH, 03550 San Juan de Alicante, Spain

The amygdala is involved in emotional behaviors and its relation with some psychiatric illnesses is subject of active research. Kainate receptors are ionotropic glutamate receptors which carry out excitatory synaptic transmission and modulation of both inhibitory and excitatory transmission between neurons. Alteration in the copy number of genes coding for Kainate receptor subunits have been linked to neuropsychiatric syndromes such as Autism and depression. Kainate receptors are heteromeric arrangements of low (GluK1-3) and high (GluK4-5) affinity subunits. To start delineating the role played by high affinity subunits (e.g. GluK4) in brain disease, we generated a transgenic mouse over-expressing grik4 in the forebrain under the control of the CaMKII promoter (C57BL/6J-Tg (Camk2a-grik4; nicknamed to GluK4over), recapitulating gene duplication observed in patients of autism. These mice displayed anhedonia, enhanced anxiety and depressive states, as well as altered social interaction, common endophenotypes associated to autism spectrum disorders. To start looking for functional correlates of this in amygdala, we studied the effect of Grik4 overexpression in the presynaptic and postsynaptic excitatory activity in the characterized cells of Basolateral (BLA) (interneurons and pyramidal cells) and central (CeLA) amygdala (late firing and regular firing GABAergic interneurons) through patch clamp recordings. Overexpression of GluK4 lead to enhanced spontaneous and external capsule-evoked glutamate mediated excitatory activity in the BLA. We also observed increased excitatory drive to the regular firing cells of CeLA. On the other hand, the excitatory input to the late firing cells of the CeLA was unchanged. Our results suggest that GluK4 subunit containing high affinity kainate receptors have a significant role in regulating prefrontal cortex to BLA excitatory transmission and synaptic transmission from the BLA to the CeLA neurons accounting for excessive anxiety and depression states underlining Autism spectrum disorders. Topic: Neuronal excitability, synapses and glia: cellular mechanisms


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IMPORTANCE OF LVA CALCIUM CURRENT IN CONTROLLING THE FIRING PATTERN OF DEVELOPING CA1 PYRAMIDAL NEURONS

A Sánchez-Aguilera 1,2, JL Sánchez-Alonso 1, MA Vicente-Torres 1, A Colino 1 1 . Facultad de Medicina, Universidad Complutense, Madrid, Spain. 2 . Centre for Developmental Neurobiology, King’s College London, London, United Kingdom.

The firing pattern of individual neurons is important for information processing and storing. During the first weeks of development, there is a transitional period during which CA1 pyramidal neurons display burst-spiking behavior in contrast to the adult regular-firing pattern. Spike afterdepolarizations (ADPs) constitute a major factor underlying burst-spiking behavior. Using currentclamp recordings, we studied ADP waveforms and firing patterns in CA1 pyramidal neurons of Wistar rats from 9 to 19 postnatal days (P9-P19). The percentage of burst-spiking neurons increased up to P16, in correlation with the emergence of an active component in the ADP. The application of low-voltage-activated (LVA) calcium channel blockers (nickel or mibefradil) suppressed the generation of the active ADP component and burst-spiking behavior. In agreement with the development of the ADP waveform and burst-spiking behavior, voltage-clamp experiments in dissociated pyramidal neurons showed an increase in the LVA calcium current in P16-19 versus P9-12. Finally, a reduction of extracellular calcium levels decreases the percentage of burst-spiking cells due to a reduction in the active component of the ADP. We conclude that a major contribution of LVA calcium channels to ADP determines the bursting capability of CA1 pyramidal neurons during a transitional postnatal period in contrast to adulthood. Topic: 2. Neuronal excitability, synapses and glia: cellular mechanisms


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DIFFERENTIAL ASSOCIATION OF GABAB RECEPTORS WITH THEIR EFFECTOR ION CHANNELS IN CEREBELLAR PURKINJE CELLS

C. Aguado1, J. Cózar2, L. de la Ossa2, F. Ciruela3, D. Kleindienst4, R. Shigemoto4, Y. Fukazawa5, R. Luján1 1 Instituto de Investigación en Discapacidades Neurológicas (IDINE), Facultad de Medicina, Universidad Castilla-La Mancha, Albacete, Spain. 2 Escuela Superior de Ingeniería Informática, Universidad de Castilla-La Mancha, Albacete, Spain. 3 IDIBELL, Facultat de Medicina, Universitat de Barcelona, L’Hospitalet de Llobregat, Spain. 4 Institute of Science and Technology Austria (IST), Klosterneuburg, Austria. 5 Faculty of Medical Science, University of Fukui, Fukui, Japan.

Metabotropic GABAB receptors mediate slow inhibitory effects presynaptically and postsynaptically through different effector signalling pathways. In presynaptic terminals activation of GABAB reduces neurotransmitter release by inhibition of Cav, whereas in postsynaptic elements, it activates GIRK channels, causing a neuronal hyperpolarization. Here, we investigated the spatial relationship of GABAB receptors with two of their effector molecules, Cav2.1 and GIRK2, using highly sensitive SDS-digested freeze-fracture replica labeling in dendritic shafts and spines of cerebellar Purkinje cells and in presynaptic active zones of parallel fibres in mouse cerebellum. We conducted single labelling for GABAB1 and double labelling of GABAB1 with Cav2.1 or GIRK2 using immunogold particles of distinct sizes. To assess whether these molecules are co-localized, we developed the Gold Particle Detection and Quantification (GPDQ) software. Immunoreactivity for GABAB1 was observed on presynaptic and, more abundantly, on postsynaptic compartments, showing both scattered and clustered distribution patterns. Quantitative analysis of GABAB1 immunoparticles revealed a somato-dendritic gradient, with the density of immunoparticles increasing from somata to dendritic spines. To understand the spatial relationship of GABAB receptors with GIRK and Cav channels, biochemical and immunohistochemical approaches were performed. Co-immunoprecipitation analysis demonstrated that GABAB receptors co-assembled with GIRK and CaV2.1 channels in the cerebellum. Using double-labelling immunoelectron microscopic techniques, a high degree of co-clustering between GABAB1 and GIRK2 was detected in dendritic spines, but mainly segregated in the dendritic shafts. In contrast, co-clustering of GABAB1 and CaV2.1 was detected in both dendritic spines and shafts, showing a closer association in the dendritic shafts. Presynaptically, co-clusters of GABAB1 and GIRK2 channels were mainly detected in the peri-active zone, whereas co-clusters of GABAB1 and CaV2.1 channels were mainly detected in the active zone. These results indicate compartment- and molecule-specific regulation of co-clustering of GABAB1 and its effector molecules, which may support compartment-specific GABAB1 functions. Supported by MINECO (BFU-2015-63769-R).


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L-DOPA OPPOSITELY REGULATES SYNAPTIC STRENGTH AND SPINE MORPHOLOGY IN D1 AND D2 STRIATAL PROJECTION NEURONS IN DYSKINESIA

LM Suarez1, O Solis1, C Aguado2, R Lujan2, R Moratalla1 1 Instituto Cajal, Consejo Superior de Investigaciones Científicas, CSIC; CIBERNED, Instituto de Salud Carlos III, 28002 Madrid, Spain. 2 Instituto de Investigación en Discapacidades Neurológicas (IDINE), Dept. Ciencias Médicas, Facultad de Medicina, Universidad de Castilla-La Mancha, Campus Biosanitario, Albacete, Spain

Dopamine depletion in Parkinson's disease (PD) produces dendritic spine loss in striatal medium spiny neurons (MSNs) and increases their excitability. However, the synaptic changes that occur in MSNs in PD, in particular those induced by chronic L-3,4-dihydroxyphenylalanine (L-DOPA) treatment, are still poorly understood. We exposed BAC-transgenic D1-tomato and D2-eGFP mice to PD and dyskinesia model paradigms, enabling cell type-specific assessment of changes in synaptic physiology and morphology. The distinct fluorescence markers allowed us to identify D1 and D2 MSNs for analysis using intracellular sharp electrode recordings, electron microscopy, and 3D reconstructions with single-cell Lucifer Yellow injections. Dopamine depletion induced spine pruning in both types of MSNs, affecting mushroom and thin spines equally. Dopamine depletion also increased firing rate in both D1- and D2-MSNs, but reduced evoked-EPSP amplitude selectively in D2-MSNs. L-DOPA treatment that produced dyskinesia differentially affected synaptic properties in D1- and D2-MSNs. In D1-MSNs, spine density remained reduced but the remaining spines were enlarged, with bigger heads and larger postsynaptic densities. These morphological changes were accompanied by facilitation of action potential firing triggered by synaptic inputs. In contrast, although L-DOPA restored the number of spines in D2-MSNs, it resulted in shortened postsynaptic densities. These changes in D2-MSNs correlated with a decrease in synaptic transmission. Our findings indicate that L-DOPA-induced dyskinesia is associated with abnormal spine morphology, modified synaptic transmission, and altered EPSP-spike coupling, with distinct effects in D1- and D2-MSNs. This work was supported by Grants from the Spanish Ministerios de Economía y Competitividad (SAF2016-48532-R) and of Sanidad Política Social e Igualdad (ISCIII, CIBERNED CB06/05/0055) and by SECITI/037/2016 from Mexico to RM. Topic: Neuronal excitability, synapses and glia: cellular mechanisms Disorders and nervous system repair


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KINETIC MICROGLIA/MACROPHAGES DENSELY POPULATE NECROTIC PALISADES IN GLIOBLASTOMA MULTIFORME

Saavedra-López, E.1, Cribaro, G.P.1, Casanova, P.V.1, Pérez-Vallés, A.2, Gallego-Sánchez, J.M.2, Barcia, Sr. C.2, Barcia, Jr. C.1 1. Institut de Neurociències, Universitat Autònoma de Barcelona, Barcelona, Spain 2. Hospital General Universitari de València, Valencia, Spain.

Gliomas are the most common primary brain tumor, and despite multiple anti-cancer therapies have been developed, as the tumor tissular architecture is yet poorly known, they remain incurable. The understanding of the tumors’ microanatomy will help to elucidate the cellular mechanisms implicated in tumor progression and suggest new and effective therapies to halt it, especially for Glioblastoma multiforme (GBM), the most aggressive form of glioma. Pseudo-palisades, a pathological hallmark of GBM, have been classically described as an area with a high density of tumor cells escaping from the harsh necrotic conditions in the core. Importantly, reports suggest this migration could contribute to the invasion of new areas. By analysing human biopsies, we spot for the first time a high immune component in pseudopalisades. More precisely, we observe tumor-associated microglia/macrophages (TAMs) structurally conforming these palisades. When modelling in vitro the hypoxic and hypoglycemic conditions in the pseudo-palisades with mouse and human cell lines, we see that when detecting low levels of oxygen, microglial cells suffer morphological changes, adopting a kinetic morphology and increasing their motility, in contrast with tumor cells. Moreover, by means of high-resolution threedimensional confocal microscopy we detect the orientation of TAMs and we suggest bidirectional motility, away and towards the necrosis. Detailed reconstructions of these areas indicate that microglia/macrophages may be guided by the fibers of the tumor cells. Hence, here we are approaching the understanding of GBM microenvironments and the network between microglial and tumor cells; therefore approaching the possibility of manipulating TAMs to eradicate the detrimental tumor cells invasion, what could bring hope to the patients diagnosed with this fatal disease. This work was supported through grants from the Spanish Ministry of Economy and Competitiveness (RYC2010-06729, SAF2010-21274, SAF2013-45178-P and SAF2015-64123-P). Topic: Neuronal excitability, synapses and glia: cellular mechanisms


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ROLE OF KINESIN-3 MOLECULAR MOTORS IN SYNAPTIC PLASTICITY

Y. Gutiérrez1, S. López García1, A. Lario1,2, C. Delevoye3, J. A. Esteban1 1 Centro de Biología Molecular Severo Ochoa. Consejo Superior de Investigaciones Científicas (CSIC)-Universidad Autónoma de Madrid (UAM). Madrid. Spain. 2 University of California San Francisco (UCSF). San Francisco. United States. 3 UMR144/Institut Curie, CNRS. PSL Research University. Paris. France.

Introduction: Synaptic plasticity mechanisms are widely studied as the cellular and molecular basis for learning and memory. A fundamental mechanism is the transport of AMPA-type glutamate receptors to and from the synapse in response to changes in neuronal activity. This continuous turnover of membrane proteins and regulated transport is mediated, among others, by Rab GTPases that drive endosomal trafficking and carried out by molecular motors and cytoskeleton associated complexes. Material and methods: In this work, using electrophysiological, biochemical and imaging techniques in organotypic hippocampal slice cultures, in combination with dominant-negative approaches and shRNAdependent knock-down, we have investigated the role of microtubule-dependent motor proteins in the regulated transport of receptors during synaptic plasticity. Results: We have found that one member of the kinesin-3 family of motor proteins is required for long-term potentiation (LTP), but does not participate in the maintenance of synaptic transmission or in longterm depression (LTD). In addition, we have found that this kinesin-3 motor protein drives a subcellular redistribution of the dendritic endosomal machinery during LTP, as monitored by live fluorescence imaging of the Rab11-interacting protein FIP2. We are also characterizing the molecular components that couple AMPA receptor subunits to the motor protein complex as well as dissecting where along the dendritic arbor these activity-induced trafficking events take place. Conclusions: Overall, these experiments are allowing us to establish specific kinesin molecular motors as key components of the activity-dependent endosomal transport of AMPA receptors during synaptic plasticity. Topic: 2. Neuronal excitability, synapses and glia: cellular mechanisms


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ECTOPIC EXPRESSION OF MELANOPSIN DRIVES ASTROCYTE CALCIUM SIGNALS Sara Mederos1, Alicia Hernández-Vivanco1, Marta Navarrete2, José A Esteban2, Gertrudis Perea1 1. Instituto Cajal (CSIC). Madrid, Spain 2. Centro de Biología Molecular Severo Ochoa (CBMSO-CSIC). Madrid, Spain

The outbreak practice of optical tools to decipher the neuronal circuits’ organization and behavioral output has transformed the neuroscience studies. Recently, these approaches have been applied to glial cells, particularly astrocytes, to unmask the consequences of astrocyte signaling in particular brain functions. Here we use a new approach based on melanopsin, a photosensitive G-protein-coupled photopigment expressed by mammalian retinal ganglion cells; which in contrast to those algae-derived opsins that directly form ion channels is coupled to IP3 signaling and elevation of intracellular Ca2+ levels. Therefore, we tested whether melanopsin was competent to stimulate Ca2+ activity in astrocytes. In order to monitor Ca2+ signals, the genetically encoded Ca2+ indicator (GECI) LckGCaMP6f and melanopsin were fused to the glial fibrillary acidic protein (GFAP) promoter and expressed in hippocampal astrocytes following an adeno-associated virus (AAV)-based strategy. Using two-photon imaging on hippocampal slices, we found that astrocytes co-expressing melanopsin and GCaMP6f showed robust Ca2+ increases in fine processes after blue light (473 nm) stimulation. The analysis of Ca2+ signals indicated a linear relationship between Ca2+ event frequency and light duration, but the amplitude and width of each event were not modified after light pulses. Consequently, viral transfection of melanopsin and GCaMP6f in mice that lack IP3 receptor-2 (Ip3r2-/), which is required for IP3-dependent Ca2+ release in astrocytes, was evaluated. After blue light stimulation, the number of active domains did not show significant changes at any light pulse tested, as well as the amplitude and width of Ca2+ events; indicating that melanopsin selectively activated IP3dependent Ca2+ signals in astrocytes. Therefore, these results describe a previously unidentified method for specific optogenetic activation of astrocytes with melanopsin, which is revealed as a meaningful G-protein signaling mechanism.


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STRUCTURAL AND FUNCTIONAL EVIDENCE FOR MODULAR ARCHITECTURE OF PRESYNAPTIC TERMINALS M.K. Raja 1, K. Mahfooz 1, S. Phan 2, E. Bushong 3, I. Pérez-Otaño 1, M. Ellisman 2,3, J.F. Wesseling 1 1 . Instituto de Neurociencias de Alicante. 2 . National Center for Microscopy and Imaging Research and 3 . Dept. of Neuroscience, University of California, San Diego, CA, USA

A recent mathematical model of the rate-limiting mechanisms in synaptic vesicle trafficking suggested that the vesicles might be linked together in chains that dock as units of one readily releasable vesicle and a small number of reserves. Here we use electron-tomography to confirm the presence of structural links between vesicles and the involvement of synapsin proteins. We then develop functional live-imaging tests to evaluate the emerging concept of heterogeneity in the probability of release (pv) among release sites, and the prediction that reserve vesicles resupplying sites with low pv do not mix laterally with reserves that supply sites with high pv. In addition to supporting the model, the results indicate that individual synapses process readily releasable vesicles with a variety of pvs in parallel. The parallel processing might allow complex frequency filtering functionality to be assembled from arrays of computationally simpler modules, nucleated by individual release sites. 1. Neuronal excitability, synapses and glia: cellular mechanisms


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INCREASED LEVELS OF BRAIN ADRENOMEDULLIN IN THE NEUROPATHOLOGY OF ALZHEIMER’S DISEASE

Hilda Ferreroa, Ignacio M. Larrayozb, Eva Martisovaa, Maite Solasa, David R. Howlettc, Paul T. Francisc, Francisco J. Gil-Bea d, Alfredo Martínezb and María J. Ramíreza a School of Pharmacy and Nutrition, University of Navarra and IdiSNA, Navarra Institute for Health Research, Pamplona, Spain. b Oncology Area, Center for Biomedical Research of La Rioja (CIBIR), Logroño, Spain. c Wolfson Centre for Age-Related Diseases-King´s College, London, UK. d Neuroscience Area, Biodonostia Health Research Institute (CIBERNED), San Sebastian, Spain.

Alzheimer’s disease (AD) is the most common form of dementia over the world. This progressive neurodegenerative disorder affects memory and cognition. Pathophysiology of AD is heavily dependent on cytoskeleton dysfunction and neuroinflammation. Adrenomedullin (AM) is a 52amino acid peptide with ubiquitous distribution. AM is involved in physiological functions such as vasodilation, hormone secretion, antimicrobial activity, cellular growth, and angiogenesis. In neurons, AM and related peptides are associated with some structural and functional cytoskeletal proteins, causing microtubule destabilization, which could contribute to loss of synaptic contacts in AD. The aim of the present work was to investigate the potential association of AM with the pathological mechanisms of AD in patient samples. Frontal cortex specimens from AD patients with severe cognitive impairment and age-matched non-demented controls were subjected to immunohistochemistry for AM, and Western blotting for AM, acetylated tubulin, and Ox-42. In addition, levels of neural cell adhesion molecule (NCAM) were quantified by ELISA, and several neurotransmitters were measured by high performance liquid chromatography (HPLC). AM immunoreactivity was particularly prominent in pyramidal cells of cortical layers IV–V, with a stronger AM labelling in apical dendrites. Western blot analysis revealed that AM is increased on prefrontal cortex of AD brain patients compared with control brains, while levels of markers of synaptic stability and function, such as acetylated tubulin and NCAM, and neurotransmitter levels were decreased. Interestingly, increases in AM statistically correlated with the decrease in these markers. Furthermore, Ox42, a microglia maker, was significantly overexpressed in AD and its expression correlates with levels of AM. It is proposed that AD patients may have neural cytoskeleton failure associated with increased of AM levels, resulting in axon transport collapse and synaptic loss. These observations suggest that reducing AM expression may constitute a new avenue to prevent/treat AD. Topic: Neuronal excitability, synapses and glia: cellular mechanisms


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ENDOCANNABINOID-DEPENDENT LONG-TERM POTENTIATION OF SYNAPTIC TRANSMISSION AT RAT BARREL CORTEX

L.E Maglio1, J.A. Noriega-Prieto1, M.J. Maraver1,2 and D. Fernández de Sevilla1 1 Departamento de Anatomía, Histología y Neurociencia, Facultad de Medicina, Universidad Autónoma de Madrid, España. 2 Centro de Investigación Mente, Cerebro y Comportamiento, Universidad de Granada; 18071 Granada, España.

Different plasticity rules along the dendritic tree of Layer 5 pyramidal neurons (L5PNs) determine how sensory information is stored at the barrel cortex. Long-term potentiation (LTP) at distal basal synapses requires the pairing of an excitatory postsynaptic potential (EPSP) with NMDA spikes in the presence of brain-derived neurotrophic factor (BDNF). We show that in thalamocortical slices low frequency stimulation at basal dendrites of L5PNs triggers a postsynaptic potential (PSP) followed by an action potential (AP) and a slow depolarization (here termed PSP-Ca2+ response) that, when facilitated after AP barrages, induces a BDNF-dependent LTP. Both PSPCa2+ response facilitation and LTP are prevented by inhibiting type 1 cannabinoid receptors (CB1R). Moreover this eCB-mediated LTP is dependent on NMDAR activation and prevented by postsynaptic intracellular BAPTA or BOTOX. In addition, only L5PNs showing eCB-mediated depolarizationinduced suppression of inhibition (DSI) present PSP-Ca2+ response facilitation and LTP, suggesting that DSI is crucial to the induction of this synaptic plasticity. Moreover, electrical stimulation at the posteromedial thalamic nucleus (POm) induced similar response and LTP. These results show a form of LTP induced by eCB-facilitated Ca2+ responses that could play a critical role in sensory processing in L5 of the barrel cortex. Topic: Neuronal excitability, synapses and glia: cellular mechanisms.


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CANNABINOID AND PURINERGIC RECEPTORS MODULATE AXON INITIAL SEGMENT PROTEINS AND NEURONAL EXCITABILITY

W. Zhang1, M. Tapia1, A. del Puerto1, A. Dominguez1, M.J. Benitez1, 2 and J.J. Garrido1 1 Instituto Cajal, Consejo Superior de Investigaciones Cientíﬁcas (CSIC), Madrid, Spain, 2 Department of Quimica Fisica Aplicada, Universidad Autónoma de Madrid, Madrid, Spain

Axon initial segment (AIS) is the place of action potential initiation and maintains neuronal polarization. AnkyrinG is the main protein necessary to maintain these functions. Moreover, recent works have demonstrated that AIS is a neuronal domain with a high degree of plasticity. Loss of AIS integrity has been described in ischemia or Alzheimer’s disease, and changes in AnkyrinG expression in psychiatric diseases. Despite AIS importance in neuronal function, our knowledge of the mechanisms modulating the AIS is limited. Our work focuses on deciphering which molecules and receptors are involved in the regulation of AIS maintenance and integrity. To study these mechanisms we use cultured hippocampal neurons and brain slices together with pharmacological treatment, gene over-expression or interference RNAs and immunocyto/histochemical and imaging techniques. We have identified that different purinergic receptors’ activity has a role in the modulation of AnkyrinG density. While the activation of ionotropic P2X7 receptor has a negative effect on AnkyrinG expression at the AIS, the metabotropic P2Y1 receptor seems to be involved in AnkyrinG maintenance. P2X7 inhibition or suppression is able to protect the AIS during a cerebral ischemia and thus, promotes neuronal survival. Besides purinergic receptors, neuronal and glial cannabinoid receptors (CBR) are able to modulate AnkyrinG expression during early development. We found that reduced activity of CB1R and CB2R reduces AnkyrinG density. We are currently investigating the role of these receptors in the modulation of AIS cytoskeleton and their possible use as therapeutic targets in brain diseases, based on their potential to adjust AIS structure and function. In summary, we demonstrate that physio/pathological stimuli can modulate AIS affecting neuronal function. This modulation seems to be highly complex and requires the combined action of different receptors. Thus, understanding which mechanisms control AIS function will help to understand brain diseases related to neuronal excitability changes.


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ROLE OF PHOSPHATIDYLINOSITOL-3-KINASES IN SYNAPTIC PLASTICITY

Sánchez-Castillo C1, Esteban JA1 1 . Centro de Biología Molecular 'Severo Ochoa', Consejo Superior de Investigaciones Científicas - Universidad Autónoma de Madrid (CSIC-UAM), Madrid, Spain

Class IA phosphatidilinositol-3-kinases (PI3Ks) are heterodimers composed by a P110 catalytic subunit and a P85 regulatory subunit and are capable of phosphorylating phosphoinositides in the cell membrane. Both PI3Ks and phosphoinositides have been linked with different forms of synaptic plasticity and age-dependent cognitive decline. There is emerging evidence of the differential regulation of the catalytic subunit isoforms (P110α, P110β and P110δ) and their specific dysregulation in brain disorders, yet the differential contribution of each isoform in synaptic plasticity is still unknown. Here, we use the shRNA technology coupled to whole-cell electrophysiological recordings in rat hippocampal slices to assess the implication of P110β in synaptic plasticity. We have found that P110β is not needed for either the maintenance of basal transmission in CA1 neurons or the induction of NMDA receptor-mediated long-term depression (LTD). We are currently investigating the role of P110β in metabotropic glutamate receptor (mGluR)-dependent LTD and NMDA receptormediated long-term potentiation (LTP). To further investigate the role of these proteins, we have produced sindbis virus overexpressing fluorescent tagged P110α and P110β. Using biochemical approaches and a constitutively active-membrane tagged version of P110α we have also demonstrated that the activation the PI3K-AKT pathway relies on the membrane localization of the P110 subunits. Thus, overexpression of the proteins per se is not sufficient to activate the pathway.


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INHIBITION OF POTASSIUM TREK CURRENTS BY BRADYKININ IN MOUSE SYMPATHETIC NEURONS P. Rivas-Ramírez1, J.A. Lamas1, L.Rueda-Ruzafa1, S. Herrera-Pérez1and A. Reboreda1 1 Laboratory of Neuroscience (CINBIO-IBIV). Faculty of Biology, University of Vigo. Vigo.

INTRODUCTION Bradykinin (BK) is a native peptide hormone inducing vasodilation, inflammation and pain. In superior cervical ganglion (SCG) neurons BK reduces adaptation and provokes depolarization of the resting membrane potential (RMP). These effects on SCG neurons have been ascribed to the inhibition of M-type potassium current (IM) implicated in RMP and adaptation. The aim of this study was to characterize the effect of BK on TREK-2 currents and to investigate the intracellular pathways involved. MATERIAL AND METHODS We carried out whole-cell (perforated-patch) and single-channel (cell-attached) recordings in primary culture of mouse SCG neurons. RESULTS The application of BK (250 nM) to the extracellular solution induced about 45% inhibition of the riluzole-activated TREK-2 current (IRIL). Single-channel recording shows that inhibition is due to the reduction in channel open probability. Using the antagonist HOE 140 we observed that the effect of BK is mediated by B2 receptors. Downstream, B2 receptor activates phospholipase C (PLC), which hydrolyzes and decreases PIP2 concentration. To study PIP2 implication, we pre-incubated DRG neurons with PIP2 (0.5 µM) and a carrier, to preclude its reduction. We observed that when keeping the PIP2 concentration, BK did not inhibit IRIL. We also blocked PKC with bisindolylmaleimide and IP3 receptor with 2-APB. Unlike IM inhibition, TREK-2 inhibition by BK is independent of the IP3 receptor and PKC activation. CONCLUSIONS We conclude that BK inhibits TREK-2 current decreasing its open probability in SCG neurons. This effect is generated by the PLC-mediated decrease in PIP2 concentration and it is independent of the IP3 receptor and PKC activation. AKNOWLEGMENTS: This research was supported by grants from MINECO: BFU2014-58999P and BFU2015-70067-REDC; Xunta de Galicia: INBIOMED-CINBIO INB1-131H-2;and GPC2015/022. FEDER. Contact: Paula Rivas Ramírez. [email protected] Topic: Neuronal excitability, synapses and glia: cellular mechanisms


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HIGH LEVELS OF 27-HYDROXYCHOLESTEROL IMPAIR PSD95 SYNTHESIS THROUGH A REST-PTBP1 SYSTEM DYSREGULATION

P. Merino-Serrais1, R. Loera-Valencia1, C. Parrado1, MA. Ismail1, S. Maioli1, E. Matute1, EM. Jimenez-Mateos2, J. DeFelipe3,4,5, Ingemar Bjorkhem6, Angel Cedazo-Minguez1. 1 Karolinska Institutet, Center for Alzheimer Research, Stockholm, Sweden 2 Royal College of Surgeons in Ireland, Dublin 2, Ireland 3 Universidad Politécnica de Madrid, Madrid, Spain 4 Instituto Cajal (CSIC), Madrid, Spain 5 Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), ISCIII, Madrid, Spain 6 Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden

Hypercholesterolemia confers a higher risk of developing Alzheimer’s disease (AD) and for dementia in older individuals. Cholesterol is not able to traverse the blood brain barrier (BBB), but it has been showed that its metabolite 27-hydroxycholesterol (27-OH) crosses the BBB from the circulation into the brain. Higher levels of 27-OH were found in brains and cerebrospinal fluid (CSF) from AD patients and have been associated with AD, memory and other neurodegenerative processes. In the present study we analysed the role in vitro and in vivo of 27-OH on the synthesis of the postsynaptic protein PSD95 through the REST-PTBP1-PSD95 signalling cascade, dendritic architecture and dendritic spine density. For this purpose, we entirely reconstructed the dendritic arbour from 70 hippocampal primary neurons using the somatodendritic marker MAP2. A 3D analysis showed in neurons treated with 27-OH a significant reduction in the complexity of the dendritic tree. To study the dendritic spines density and the postsynaptic density, we stained hippocampal primary neurons with phalloidin and PSD95 markers respectively. We found an extreme lack of dendritic spines and postsynaptic densities in neurons treated with 27-OH. A series of molecular biology tests showed in neurons treated with 27-OH a dysregulation in the RESTPTBP1-PSD95 signalling cascade leading on an impaired PSD95 synthesis. In the transgenic mouse model that overexpress the enzyme responsible for converting cholesterol to 27-OH (Cyp27a1), we found a significant reduction on the PSD95 protein levels and a dysregulation in the REST-PTBP1PSD95 signalling cascade. These data further suggest that high levels of 27-OH impair the REST-PTBP1-PSD95 signalling cascade, the complexity of the dendritic tree and the dendritic spine density. Our finding sheds light on the mechanism by which hypercholesterolemia influence PSD95 synthesis and dendritic spine density and thereby contributes to cognitive decline in AD and other neurodegenerative disorders.


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HIPPOCAMPAL CHANGES IN THE EXPRESSION OF RECEPTORS AND CHANNELS IN ALZHEIMER´S DISEASE.

A. Martín-Belmonte1, C. Aguado1, R. Alfaro1, Y. Fukazawa2, R. Luján1. 1 Instituto de Discapacidades Neurológicas (IDINE), Facultad de Medicina, Universidad de Castilla-La Mancha. Albacete, Spain. 2 Faculty of Medical Science, University of Fukui, Fukui, Japan.

Alzheimer’s disease (AD) is the most prevalent form of dementia in the elderly and represents a major public health problem. AD is a progressive neurodegenerative disease associated with early learning and memory impairments. The pathological lesion of AD includes amyloid plaques, neurofibrillary tangles and synaptic loss. Of the three, synapse loss is the strongest anatomical correlate of the degree of clinical impairment. However, the molecular pathological entity of synaptic loss remains elusive. AD is linked with mutations in amyloid precursor protein (APP) that generates amyloid β protein (Aβ), which ultimately aggregate into senile plaques. Some evidence point out that Aβ affects synaptic plasticity and transmission via changes in expression and function of AMPA and NMDA receptors. Their activity is necessary for hippocampal LTP, so receptor loss affects plasticity in the early stages of AD. However, information on the involvement of other receptors and ion channels related with glutamatergic synapses in AD is very scarce. Using histoblot and immunohistochemical techniques we analysed the expression and distribution patterns of GABAB receptors, mGlu5 receptors and the GIRK2 ion channel in the hippocampus of both the APPPS1 mouse model and brain tissue from AD patients. In the APP-PS1 mouse model, we studied changes in expression and distribution at 6 and 12 months of age. Using histoblot approaches, our preliminary results indicate that the three proteins GABAB1, mGlu5 and GIRK2 are downregulated in the hippocampus. Using the immunohistochemical technique at the light microscopic level in human tissue from normal and AD patients, our data indicate that immunoreactivity for GABAB1, mGlu5 and GIRK2 are significantly reduced in pyramidal cells of the hippocampus. Altogether, these results suggest that in addition of NMDA, other receptors and ion channels associated with glutamatergic synapses are altered in AD. Neuronal excitability, synapses and glia: cellular mechanisms


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GI/O SIGNALING PATHWAYS INHIBIT NEURONS BUT ACTIVATE ASTROCYTES A. Covelo*, C. Durkee*, S. Jamison, A. Araque University of Minnesota. Minneapolis, Minnesota, 55455,USA *Equal contribution

Introduction: Astrocytes express receptors that detect synaptically-released neurotransmitters, resulting in a calcium increase and a downstream release of gliotransmitters that regulate synaptic function. The most-studied mechanism that elevates astrocyte calcium is through Gq-linked Gprotein-coupled receptor (GPCR) and PLC-dependent signaling cascades. However, astrocytes also express Gi/o-linked GPCRs. In neurons, Gq-PLC activation results in excitation in form of depolarization and intracellular calcium elevations, whereas Gi/o activation results in inhibition. While Gq-PLC activation is well known to activate astrocytes through calcium elevations, the effects of Gi/o signaling is yet largely undetermined. Material and methods: To characterize the effects of activating Gq- and Gi/o-linked intracellular cascades in neurons and astrocytes, we used Designer Receptors Exclusively Activated by Designer Drugs (DREADDs). Adeno-associated viruses carrying either Gq- or Gi/o-linked DREADDs were targeted to hippocampal neurons or astrocytes. We measured changes in neuronal excitability and astrocytic calcium after activation of either Gq or Gi/o GPCRs, either using endogenous ligands or the DREADDs synthetic ligand Clozapine N-oxide (CNO). Results: We found that Gq activation in both neurons and astrocytes led to cellular activation. In neurons, Gq activation induced calcium increases, inward currents, membrane depolarization, and action potential firing facilitation. In astrocytes, Gq activation induced calcium increases in both soma and processes. In contrast, whereas neuronal Gi/o activation induced cellular inhibition (outward currents, membrane hyperpolarization and action potential suppression), astrocytic Gi/o activation led to calcium increases in both somas and processes. Additionally, astrocytic stimulation by either Gq or Gi/o GPCRs increased excitability in nearby neurons in the form of slow inward currents and action potential firing facilitation, suggesting the release of astrocytic glutamate downstream of calcium elevations. Conclusions: These results indicate that while activation of the different GPCR pathways in neurons led to either excitation or inhibition, activation in astrocytes of the examined GPCR pathways led only to excitation. Topic: Neuronal excitability, synapses and glia: cellular mechanisms


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REGULATION OF AMPA RECEPTOR SYNAPTIC FUNCTION BY GSK3 J.E. Draffin 1, J.A. Esteban1 1 Centro de Biología Molecular ‘Severo Ochoa’. CSIC/Universidad Autónoma de Madrid, Madrid

Glycogen synthase kinase-3 (GSK3) is a threonine-serine kinase with pleiotropic actions in the central nervous system. Although GSK3 has been implicated in neurological disorders characterised by synaptic dysfunction, including Alzheimer's disease, its actions at the synapse remain obscure. Here, we have examined the role of GSK3 in modulating AMPA receptor-mediated current in CA1 hippocampal neurons. Using whole-cell and field potential recording in rat hippocampal slices, we have found that acute application of structurally unrelated selective inhibitors of GSK3 leads to a run-down of evoked AMPAR-mediated currents. Consistent with this observation, overnight application of these inhibitors produces a decrease in AMPA/NMDA ratio of CA1 pyramidal neurons, and shRNA-mediated knockdown of GSK3 results in a decrease in AMPAR-mediated current. In further support of the role of GSK3 in this depression of synaptic responses, we found that activation of Akt, a negative regulator of GSK3 activity, induces a similar run-down of AMPAR-mediated currents, and occludes run-down induced by GSK3 inhibition. Using electrophysiologically-tagged recombinant AMPA receptors and immunogold electron microscopy of endogenous receptors, we identified GluA2 as the AMPA receptor subunit removed from the synapse during inhibition of GSK3. Previous work has shown that activity of GSK3 is required for the induction of long-term depression (LTD) of synaptic responses, but the methods used were incapable of distinguishing between GSK3 isoforms. Here, via specific knockdown of each isoform, we show that GSK3 alpha (and not, as has been assumed, beta) is the isoform required for long-term depression (LTD). Therefore, we propose a dual role for GSK3: in the maintenance of basal synaptic transmission, and in the removal of AMPA receptors during LTD. Neuronal excitability, synapses and glia: cellular mechanisms


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PLASTICITY IN THE ADULT AUDITORY SYSTEM AFTER DEAFNESS: CHANGES IN THE EXPRESSION OF AMPA RECEPTORS AND POTASSIUM CHANNELS IN THE AUDITORY BRAINSTEM

C.M. Poveda1, M. Valero1, M. Pernía2, M. A. Merchán2, J.M. Juiz1 1 . Instituto de Investigación en Discapacidades Neurológicas, Facultad de Medicina. Universidad de Castilla-La Mancha, Campus de Albacete, Albacete. 2 . Instituto de Neurociencias de Castilla y León, Universidad de Salamanca, Salamanca.

We analyzed whether and how peripheral auditory deprivation affects the expression of key molecules for signal processing in the cochlear nucleus (CN), the first central relay station of the auditory pathway in the brainstem, and the inferior colliculus (IC), the main auditory integration center in the midbrain. Following bilateral mechanical lesion of the cochlea in adult rats, animals were assigned to three survival groups: 1 day, 15 days or 90 days. Variantions in the expression of the main AMPA glutamate receptor subunits in the auditory pathway (GluR2, GluR3 and GluR4), the activity marker Arc/Arg3.1, involved in AMPA receptor subunit trafficking, and Kv1.1 and Kv3.1b, two voltage-dependent potassium channels involved in propagating auditory timing information, were tested, in the CN and IC, by qPCR , western blot and quantitative immunohistochemistry. The most relevant change in the CN, one day after deafness, is increased levels of GluR4 mRNA and protein. Fifteen days after deprivation, GluR2 levels are increased, and so is Arc/Arg3.1. At 90 days postlesion, a clear increase in Kv1.1 and Kv3.1b expression levels is detected. In the IC, one day after deprivation, GluR4 is also increased. Increased GluR4 levels are maintained at 15 days postlesion. GluR3 levels also seem to be increased, whereas GluR2 levels are decreased, along with Arc/Arg3.1. Similar levels are found at 90 days postlesion. Kv1.1 and Kv3.1b showed minimal changes at any time postlesion. These findings predict that the postsynaptic currents mediated by AMPA receptors may change in the CN and IC after auditory deprivation as an adaptation to altered input. The fact that GluR2 subunits increase in the CN and decrease in the IC, suggests differences in the synaptic handling of Ca++. Increased expression of Kv1.1 and Kv3.1b in the CN at long-term after deprivation suggests adaptive changes in excitability close the lesion site. Supported by MINECO SAF 2016 78898 C2-1-R Topic: Neuronal excitability, synapses and glia: cellular mechanisms Disorders and nervous system repair


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INHIBITION OF MTOR SIGNALING AND PRODUCTION OF PLASTICITY PROTEINS BY GLUN3A SUBUNITS Conde-Dusman, M.J. 1,2, Dey, P.N. 1, García-Rabaneda, L. 1,2, Martínez-Turrillas, R. 1 & Pérez-Otaño, I. 1,2 1 . Centro de Investigación Médica Aplicada (CIMA), Universidad de Navarra, Pamplona (Spain). 2 . Instituto de Neurociencias (CSIC-UMH), San Juan de Alicante (Spain).

Early brain development is characterized by an overproduction of synapses which make weak functional connections between neurons. Neuronal activity later refines this basic circuitry by strengthening and maintaining subsets of connections but suppressing others. A main regulator of this type of synaptic refinements is a subtype of NMDA-type glutamate receptors that contain GluN3A subunits (GluN3A-NMDARs). GluN3A-NMDARs are typically expressed at early postnatal and juvenile stages, when intense synaptic refinements are taking place, and act as dominant negative regulators of synaptic maturation and stabilization normally driven by mature NMDARs (GluN1/ GluN2 subunits). Whereas these inhibitory GluN3A roles seem to be critical for directing the targeted pruning of certain synapses and preventing premature synapse maturation/ stabilization in developing brains1, its expression in the adult brain can be pathological and triggers synapse loss in major mental disorders as schizophrenia or depression2,3. Here we study the modulatory effects of GluN3A expression on activity-dependent signaling pathways that underlie synapse development and memory consolidation. For that purpose we induced synaptic activity in two different systems: primary cortical neuronal cultures of rat embryos infected with lentiviral vectors to overexpress GluN3A subunits, and cultures from Grin3a -/- mice. In GluN3A overexpressing neurons we observed a selective inhibition of a set of activity and NMDAR-regulated pathways, standing out among them the mTOR pathway, a key regulator of protein translation. The induction of plasticity-proteins such as the immediate early genes Arc and cFos was inhibited despite normal mRNA production, pointing towards a role of GluN3A in limiting protein translation. Conversely, young Grin3a -/- mice cortical cultures (DIV4-DIV7) displayed a hyperactive mTOR signaling relative to their wild-type counterparts that was associated with a premature increase of the ratio of GluN2A/GluN2B subunits. Current work aims to elucidate the mechanisms underlying the selectivity of GluN3A effects on NMDAR signaling, considering a possible metabotrophic effect due to the interaction between the mTOR-activating GTPase Rheb and the actin cytoskeleton scaffold GIT1 with GluN3A subunits1, or a modulation by GluN3A of the synaptic NMDAR composition which could lead to downstream mechanisms described above. We are also investigating whether altered mTOR underlies phenotypes characteristic of Grin3a KO mice including altered cognition of elevated spine densities. References 1. Pérez-Otaño et al., Nature Review Neuroscience (2016). 2. Roberts, A.C. et al., Neuron (2009). 3. Marco, S. et al., Nature Medicine (2013). Work was funded by the UTE project CIMA, a Tatiana Pérez de Guzmán el Bueno fellowship (to M.J.C.D.), a Juan de la Cierva-Incorporation Fellowship (IJCI-2014-19056) (to L.G.R), a NARSAD Independent Investigator Award and grants from the MINECO (CSD2008-00005, SAF201348983R, SAF2016-80895-R) (to I.P.O). Neuronal excitability, synapses and glia: cellular mechanisms Cognitive and Behavioral Neuroscience


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BIDIRECTIONAL MODULATION OF GLUTAMATERGIC SYNAPTIC TRANSMISSION BY mGlu7 RECEPTORS AT SC-CA1 HIPPOCAMPAL SYNAPSES Ricardo Martin1,2, Jose Javier Ferrero1,2, Andrea Collado1,2, Magdalena Torres1,2, José Sánchez-Prieto1,2 1 Departamento de Bioquímica, Facultad de Veterinaria, Universidad Complutense, 28040 Madrid, Spain. 2 Instituto de Investigación Sanitaria del Hospital Clínico San Carlos, Madrid 28040, Spain.

By reducing the activity of voltage dependent Ca2+ channels, metabotropic glutamate (mGlu) receptor 7 can inhibit excitatory synaptic transmission. These mGlu7 receptors can also activate phospholipase C (PLC) and promote phosphatidylinositol (4,5) bisphosphate (PIP2) hydrolysis to generate inositol trisphosphate (IP3), which in turn releases Ca2+ from intracellular stores and diacylglycerol (DAG), an activator of proteins containing DAG-binding domains like Munc13 and protein kinase C (PKC). However, the effects of this signaling on synaptic transmission are not yet clear. Using electrophysiological, pharmacological and genetic approaches we found that prolonged activation of mGlu7 receptors with the agonist L-AP4 first reduces and then enhances the amplitude of EPSCs through a presynaptic effect that changes the frequency but not the amplitude of mEPSCs, and that also alters the paired pulse ratio. Pertussis toxin blocks the inhibitory response, while the PLC inhibitor U73122, the inhibitor of DAG binding calphostin C and the absence of the RIM1α protein, all prevent receptor mediated potentiation. Moreover, electron microscopy showed that this DAG-dependent modulation of the release machinery drives synaptic vesicles closer to the active zone plasma membrane. Endogenous activation of mGlu7 receptors only potentiates synaptic transmission and this response, which develops faster than when the receptor is activated exogenously, is also prevented by the PLC inhibitor U-73122. Thus, we conclude that exogenously activated mGlu7 receptors exert a bidirectional modulation of excitatory synaptic transmission at hippocampal SC-CA1 synapses whereas only potentiation prevails after endogenous activation.


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RESTRAINT STRESS IMPAIRS CANNABINOID 1 (CB1) RECEPTORMEDIATED CONTROL OF GLUTAMATERGIC TRANSMISSION AND PLASTICITY IN YOUNG ADULT MICE DENTATE GYRUS N. Royo1,2, N. Puente1,2, S. Peñasco1,2, L. Reguero1,2 , I. Bonilla1.2, J.L. Mendizabal-Zubiaga1,2, I. Elezgarai1,2, G. García Del Caño4, S. Barrondo4, J. Sallés4 and P. Grandes1,2,3 1

Faculty of Medicine and Nursery, University of the Basque Country ( UPV/EHU), Leioa, Spain. 2Achucarro Basque Center for Neuroscience, Bizkaia Science and Technology Park, Zamudio, Spain. 3Division of Medical Sciences, University of Victoria. Victoria, BC, Canada. 4Faculty of Pharmacy, University of the Basque Country (UPV/EHU). Vitoria. Spain

The endocannabinoid (eCB) system plays a central role in the control of stress responses, also hippocampal CB1 receptor (CB1R) expression and binding capacity were shown to be altered under stress. However, structural and functional changes of CB1Rs at synapses of the stressinvolved dentate gyrus (DG) are poorly reported. Western blots displayed a decrease in DGL-α and PLCβ1 levels in hippocampus of acute (AC) and chronic (CR) restraint stress versus non stress mice. However, the CB1R expression was reduced in AC (P18 months) continuously superfused with physiological saline solution at 34ºC. Background activity at basal temperature (34ºC) and the responses to cooling ramps (modifying the temperature of the perfusion solution from 34 to 15ºC) and TRP channel agonists (menthol, ATIC; added to the perfusion solution) effect were analyzed. Results. No significant differences were found in background NTI activity at 34ºC of cold nerve terminals recorded in aged WT and TRPA1-KO mice (7.7±1.2 imp/s, n=11, vs 4.5±2.2 imp/s, n=10, P=0.22, t-test), neither in the cooling threshold (32.2±0.5ºC vs 32.3±0.5ºC, P=0.47) nor in the peak response to cold (16.9±1.9 Hz vs 14.0±4.0 Hz, P= 0.84). Overall, NTI activity of aged WT and TRPA1-KO mice was higher than in young, 5-6 months old WT mice (3.8±0.8 imp/s, n=10). Conclusions. Activity of corneal cold thermoreceptors increases with age. No differences were found in NTI and cooling responses of cold thermoreceptor terminals recorded in WT and TRPA1KO corneas of aged mice suggesting that TRPA1 is no essential for corneal cold thermoreceptor activity signally temperature reductions. Supported by SAF2014-54518-C3-1-R MINECO, Spain, and ERDF, European Commission.


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STATISTICAL WIRING OF VISUAL CORTICAL RECEPTIVE FIELDS AND MAPS A.J. Valiño 1, J.R. Brotons-Mas 1, S. Sala-Pla 1, & L.M. Martínez 1 1 . Instituto de Neurociencias de Alicante. CSIC-Universidad Miguel Hernández, San Juan de Alicante, Alicante.

Neurons in the primary visual cortex (V1) of most mammals respond only to a restricted set of stimulus orientations. Furthermore, in some species but not in others, V1 cells with similar orientation preferences tend to cluster together in an orderly fashion giving rise to the so called cortical orientation preference maps (OPMs). The developmental rules underlying the emergence of cortical receptive fields and maps are highly debated. Over the years, contrasting intracortical and feedforward models have been proposed to explain the emergence and function of this salient feature of cortical organization. Both types of models, however, have in common that they largely neglect the potential role that the thalamus plays in this process. Recently, we have used a powerful combination of experimental and computational techniques to demonstrate that the retinothalamic circuit is optimized to increase the resolution of the retinal output on its way to V1 through a straight process of information upsampling and interpolation (Martinez et al., 2014). Here, we use a similar approach to show that the probabilistic, convergent connectivity from retina to LGN required to increase visual resolution transforms significantly the thalamic representation of the retinal mosaics generating partially segregated thalamic domains of On- and Off-center cells. We demonstrate that this new thalamic structure is essential for the emergence and stability of cortical receptive fields and orientation maps: First, our results revealed that these cortical features perfectly correlate with the arranging of the thalamic ON and OFF domains. Second, they also show that the periodicity and stability of the cortical orientation map depend critically on the biological constraint imposed by the upsampling and interpolation performed in the thalamus. Finally, the retinothalamic rewiring allows to maintain large values of thalamocortical convergence, without requiring complex developmental rules or very precise patterns of spontaneous or visually driven activity. -

Topic: Systems Neuroscience


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HOMEOSTATIC CONTROL OF THE CORNEAL SURFACE TEMPERATURE IS IMPAIRED IN AGED MICE LACKING THE EXPRESSION OF TRPM8

A. Aracil, M.C. Acosta, J. Gallar Instituto de Neurociencias, Universidad Miguel Hernandez-CSIC, Sant Joan d’Alacant, Alicante, Spain.

Introduction: ‘Low threshold’ cold thermoreceptors express TRMP8, a member of the transientreceptor proteins that is activated by innocuous temperature decreases and by elevations of the extracellular fluid osmolality. It has been suggested that neurons expressing TRPM8 contribute to the control of basal tear production (BTP) in young adult mice. BTP is increased in aged animals and therefore we were interested in exploring whether TRPM8 could be involved in this process. Methods: C57BL6 (WT) and TRPM8-KO aged male mice (~27 months old; n=6 eyes of 3 animals/group) were anesthetized (1.5% isoflurane) and placed in a restrainer. Body temperature was fixed at 38 ºC with a homeothermic blanket system. Room temperature and relative humidity were registered. The corneal surface temperature (CST) was measured from images taken with an infrared thermographic camera. Basal tear production (BTP) was estimated using phenol red threads. CST and BTP were measured 10 min after instillation of a 2.5 µL drop of phosphatebuffered saline (PBS) or 2% lidocaine in PBS, all at room temperature. Results: After PBS instillation, CST was significantly lower in TRPM8-KO mice (32.14 ± 0.25ºC vs 33.35 ± 0.35ºC, KO vs WT, p=0.006, t-test) and no differences were noted in the BTP (17.1 ± 2.4 mm vs 13.8 ± 3.4 mm wet thread length, KO vs WT, p=0.446, t-test). After lidocaine, CST (30.06 ± 0.30ºC KO, p 0 . Importantly, these predictions were robust for a wide range of model parameters and specific for a model with attractor dynamics. Moreover, other models that consider optimal evidence integration yielded completely different predictions. To test the predictions we collected MEG data from sixteen human subjects and electrophysiology data from 6 rats while they were performing a 2AFC. Preliminary behavioral analysis showed that the performance and the stimulus integration varied with s in heterogeneous ways across subjects. We plan to use the electrophysiological data to detect transitions in a single trial. Using the temporal evolution of the decision variable and the behavioural data we will fit a potential that will help us to understand the dynamics of evidence integration in each subject.


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PHASE-LOCKED STATES NEURONAL NETWORKS

IN

THE


OSCILLATORY

REGIME

OF

A. Pérez-Cervera 1, G. Huguet 1, T. M-Seara. 1 1 . Facultat de Matemàtiques. Universitat Politècnica de Catalunya, Barcelona

Background oscillations, reflecting the excitability of neurons, are ubiquitous in the brain. Although the functional role of oscillations is still unknown, some studies have conjectured that when spikes sent by one population reach the other population at their peaks of excitability, then the information transmission between two oscillating neuronal groups is more effective (Fries, 2005). In this context, the phase relationship between oscillating neuronal populations may have implications in neuronal communication between brain areas. The classical approach to study synchronization between oscillators is based on the Phase Response Curve (PRC). The PRC measures the phase-shift resulting from perturbing a neural oscillator at different phases of the cycle. It provides useful information to study the dynamics resulting from weak interactions between neural oscillators. In this project we consider a canonical network model (Wilson & Cowan, 1972) consisting of a single population of excitatory cells and a single population of inhibitory cells (E-I network) displaying an oscillatory behavior and perturb it with a time-dependent periodic input. During an oscillation, the excitability of the excitatory population is modulated across the inhibitory action, as it creates windows of opportunity where excitatory cells can respond effectively to a certain input. By means of rigorous mathematical analysis and powerful computational techniques, we study the different phase-locked states between the perturbed oscillator and the external periodic input. Our results enlarge the classical PRC approach to study synchronization. This poster aims at showing these techniques to the experimental community in order apply them to problems of neural oscillatory behaviour and rhythms generation. Topic: Theoretical and Computational Neuroscience


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Poster Topic s

6 .

Disorders and Nervous System Repair


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PROPHYLACTIC CHRONIC ZINC ADMINISTRATION INCREASES NEUROINFLAMMATION IN A HYPOXIA-ISCHEMIA RAT MODEL

C. Tomás Sánchez 1, V. M. Blanco Álvarez 1, J. A. González Barrios 2, D. Martínez Fong 3, E. Brambila Colombres 1, M. Torres Soto 1, A. González Vázquez 1, A. K. Aguilar Peralta 1, D. I. Limón 1, B. A. León Chávez 1 1 . Facultad de Ciencias Químicas, Benemerita Universidad Autonoma de Puebla, México 2 . Hospital regional 1º de Octubre, ISSSTE, México 3 . Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, México

Introduction. Zinc has a dual role, protector or toxic, depending on its concentration. Acute and subacute administration of zinc exerts neuroprotective effects in hypoxia-ischemia animal models; yet the effect of chronic administration of zinc still remains unknown. Methods. Rats were grouped as follows: (1) CZn15d, control rats treated with chronic administration of zinc (ZnCl2; 0.5 mg/kg every 24 h for 14 days), their brains were obtained on day 15. (2) Zn15d+CCAO, rats with chronic administration of zinc that were subjected to CCAO 24 h after the last administration of zinc; their brains were obtained at 8 hour and 7 days post-reperfusion and (3); Control, intact rats that did not receive surgery and zinc administration. After CCAO, we measured zinc levels by atomic absorption spectrophotometry, nitrites by Griess method, and lipoperoxidation by Gerard-Monnier assay. We also used qRT-PCR to measure mRNA expression of 84 genes coding for cytokines, chemokines and their receptors, and ELISA to quantify nitrotyrosine, chemokines and their receptors. In addition, we made histopathological studies in the temporoparietal cortexhippocampus at different time points and evaluated long-term memory using a Morris-Water maze. Results. Following CCAO, a significant increase in nitrosative stress, inflammatory chemokines/receptors and cell death was observed after 8 h, and a 2.5-fold increase in zinc levels was detected after 7 days. Although, CXCL12 and FGF2 protein levels were significantly increased, the long-term memory was impaired at day 12 post-reperfusion in the Zn+CCAO group. Conclusion. Our data suggest that the chronic administration of zinc at tolerable doses causes nitrosative stress, toxic zinc accumulation, and neuroinflammation, which might account for the neuronal death and cerebral dysfunction after CCAO. 6. Disorders and nervous system repair


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CHRONIC SELENIUM ADMINISTRATION FROM PREGNANCY CAUSES TOXICITY IN THE FEMALE OFFSPRING OF THE RAT

A. González Vázquez 1, A. K. Aguilar Peralta 1, R. Gómez Díaz 1, D. Martínez Fong 2, J. A. González Barrios 3, A. Ugarte 4, J.R. Eguibar 4, B. A. León Chávez 1. 1 . Facultad de Ciencias Químicas, Benemérita Universidad Autónoma de Puebla, Puebla, México. 2. Depto. de Fisiología, Biofísica y Neurociencias, CINVESTAV, Ciudad de México, México. 3 . Hospital Regional 1º de Octubre, ISSSTE, Ciudad de México, México. 4 . Instituto de Fisiología, Benemérita Universidad Autónoma de Puebla, Puebla, México.

Introduction. Selenosis is a health problem caused by intake of water and foods products contaminated with selenium. The recommended selenium maximum limits in foods and dietary supplement are 400 µg/day. We aimed to determine whether chronic administration of selenium causes differential effect on nitrosative stress in offspring of Sprague-Dawley rats. Methods. We evaluated learning and memory by the Morris water maze in the adult female supplemented with sodium selenite (3 ppm) through drinking water since the first month of age. Then, females were got pregnant and continued receiving the selenium dose along pregnancy. The offspring continued receiving the respective dose of selenium up to 2 months of age. We also measured nitrite levels using the Griess assay (nitrosative stress) and MDA-4-HDA levels using the Gerard-Monnier assay (lipoperoxidation) in different brain regions (cerebral cortex, hippocampus, cerebellum and brainstem) and organs (small intestine, serum, liver, lung, pancreas and kidney). Results. Selenium supplementation at 3 ppm improved learning and memory in the female offspring, without causing nitrosative stress in different brain regions, increasing only lipoperoxidation in stomach (356 ± 93%) and kidney (118 ±17%). However, the female offspring show signs of selenosis including hair loss, fatigue and irritability, with a high mortality ratio (70%), compared with the mortality of male offspring (20%) at 2-month-old. In addition, lipoperoxidation levels increased by 700 ± 115% in the brainstem, 746 ± 47% in serum, 88 ± 24% in small intestine, and 103 ± 35% in kidneys, and the nitrite levels also increased by 230 ± 40% in the brainstem in females offspring compared with control group Conclusions: The selenium supplementation in high doses since embryonic development just causes selenosis in the female offspring, showing lethal effect during puberty. 6. Disorders and nervous system repair


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PROPHYLACTIC CHRONIC SELENIUM OR ZINC ADMINISTRATION PREVENTS APOPTOSIS CAUSED BY CEREBRAL HYPOXIA-ISCHEMIA IN THE RAT

A.K. Aguilar Peralta 1, C. Tomás Sánchez 1, V.M. Blanco Álvarez 1, A. González Vázquez 1, D. Martínez Fong 2, J.A. González Barrios 3, E. Brambila Colombres 1, M. Torres Soto 1, B.A. León Chávez 1 1 . Facultad de Ciencias Químicas, Benemérita Universidad Autónoma de Puebla, México 2 . Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, México 3 . Laboratorio de Medicina Genómica, Hospital regional 1º de Octubre, ISSSTE, México

Introduction. We previously showed that zinc (0.5 mg/Kg) caused cellular damage in the cerebral cortex. Herein, we evaluated the effect of prophylactic zinc and selenium administration on the nitrosative stress and cell death. Methods. Male Rats were grouped as follows: 1) Control without treatment; 2) CCAO, common carotid artery occlusion by 10 minutes; 3) Zn15d, intraperitoneal chronic administration of ZnCl2 at 0.2 mg/kg each 24 h during 14 days, 4) Se15d, Na2SeO3 at 6 μg/Kg each 24h during 14 days; 5) Zn15d+CCAO and 6) Se15d+CCAO; both groups with treatment were subjected to CCAO 24 h after the last administration and 7) Se-Zn15d+CCAO; co-administration of selenium and zinc before CCAO. Brains were dissected out at 3, 6, 24 and 168h post-reperfusion, then nitrites were determined by Griess method and lipoperoxidation by Gerard-Monnier assay. Histopathology studies using hematoxylin and eosin staining were made in cerebral cortex and hippocampus tissues at 168h post-reperfusion. Results. Chronic zinc doses decreased lipoperoxidation by 89 + 2% at 24h post-reperfusion in the cerebral cortex. Selenium administration did not prevent the CCAO-induced lipoperoxidation. SeZn15d+CCAO group increased by 49 + 5% of nitrites at 168h post-reperfusion. Histopathology studies showed that prophylactic selenium decreased the number of pyknotic cells caused by CCAO by 92% in the cerebral cortex, 72% in dentate gyrus (DG) and 68% in CA3. The prophylactic zinc administration decreased pyknotic cells by 89% in the cerebral cortex, 80% in DG and 58% in CA3. The effect of prophylactic Se+Zn administration was not different from the effect caused by the individual elements. Conclusion. The prophylactic chronic administration of selenium or zinc prevents the apoptosis caused by cerebral hypoxia-ischemia in the rat, thus suggesting a neuroprotector effect against cerebrovascular diseases. However, the co-administration of both elements has not a synergic effect. data. 6. Disorders and nervous system repair


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EFFECTS OF NANOCRYSTALLINE GLASS-LIKE CARBON THIN FILMS IN THE SN4741 DOPAMINERGIC CELL PARKINSON MODEL N. Rodriguez-Losada1, P. Romero2, G. Estivill-Turrus3, R. Guzmán de Villoria4, J.A. Aguirre 1 1 . Facultad de Medicina, Universidad de Medicina, Malaga, Spain 2 . IMDEA Material Institute, Getafe, Madrid, Spain 3 . Unidad de Clínica de Neurociencia, Biomedical Research Institute of Malaga (IBIMA), Regional University Hospital Malaga, Málaga, Spain 4 .FIDAMC, Foundation for the Research, Development and Application of Composite Materials, Getafe, Madrid, Spain

The interest in carbon nanomaterials has grown within the last decade in view of a wide variety of applications. In this work we test the biocompatibility of a particular nanometer-thin nanocrystalline glass-like carbon films (NGLC), a disordered structure of graphene flakes joined by carbon matrix [1]. We used a cell line (SN4741) from substantia nigra dopaminergic cells derived from transgenic mouse embryo cells [2]. Some cells were cultured on top of NGLC films (5, 20 and 80 nm) and other with NGLC microflakes (approx. 5-10 mm2) in increasing concentrations: 1, 5, 10, 20 and 50 μg/ml, during 24 h, 3 days and 7 days. Cells growing in normal conditions were defined under culture with DMEM supplemented with 10% FCS. Microflakes were resuspended in DMEM at the stock concentration (2 g/l). We use 96 well plates (Corning) using 2500 cells per well. For MTT analysis a positive control with a 10% Triton X-100 and a negative control. As apoptosis/necrosis assay we used LIVE/DEAD® Viability/Cytotoxicity Assay Kit (Invitrogen). In a separate experiment, cells were cultured on top of the NGLC films for 7 days. Primary antibodies: anti-synaptophysin (SYP, clone SY38, Chemicon) and goat anti-GIRK2 (G-protein-regulated inward-rectifier potassium channel 2 protein) (Abcom) for immunofluorescence. WB was performed with a polyclonal antirabbit proliferating cell nuclear antigen (PCNA). We demonstrate the biocompatibility with different concentration of NGLC varying the degree of survival from a low concentration (1 g/ml) in the first 24 h to high concentrations (20-50 g/ml) after 7 days, corroborated by the PCNA analysis. Cells cultured on top of the film showed after 7 days axonal-like alignment and edge orientation as well as net-like images. Neuronal functionality was demonstrated through the analysis of coexistence between SYP and GIRK2. This nanomaterial could offer a powerful platform for biomedical applications such as neural tissue engineering. 6. Disorders and nervous system repair


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INHIBITION OF NITRIC OXIDE SYNTHASES DECREASES THE RETENTION OF LONG-TERM MEMORY BY THE ABSENCE OF TROPHIC FACTORS AFTER BRAIN HYPOXIA-ISCHEMIA IN THE RAT

V.M. Blanco Alvarez1, A. González Vázquez1, A.K. Aguilar Peralta1, C. Tomás Sánchez1, D. Martinez Fong2, J.A. González Barrios3, L. Millan Perez Peña, E. Brambila1, D. Limón1, B.A. Leon Chavez1. 1 . Facultad de Ciencias Químicas, Benemérita Universidad Autónoma de Puebla. 2 . Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional. 3 . Laboratorio de Medicina Genómica, Hospital regional 1º de Octubre.

Introduction. Previous studies have shown that N-nitro-L-arginine-methylester [L-NAME], a nonselective inhibitor of nitric oxide synthases (NOS), 1h before of common carotid artery occlusion (CCAO) prevents the apoptosis and nitrosative stress caused by cerebral hypoxia-ischemia in the late phase, thus suggesting a neuroprotector effect against cerebrovascular diseases. Herein, we evaluated the effect of superacute administration of L-NAME 1 h before CCAO on growth factors, transcription factors and nitric oxide synthase isoforms at 8 h post-reperfusion. In addition, we evaluated the recovery of cognitive abilities in the Morris water maze. Methods. Male Wistar rats were grouped as follows: (1) Control without treatment, (2) CCAO for 10 minutes; (3) intraperitoneal superacute administration of L-NAME (10 mg/kg), 1 h before CCAO. Their brains were dissected out at 8 h post-reperfusion, and divided in cerebral cortex and hippocampus. The expression of nNOS, iNOS, eNOS, pERK1/2, pIkB/pNFκB, SDF, BDNF, EGFR and NGF was assessed by ELISA. Learning in Morris water maze was achieved by daily training during 5 days. Long-term memory was evaluated on day 7 after learning. Results. Superacute administration of L-NAME before CCAO at 8 h post reperfusion decreased nNOS levels (-25.27% ± 2.06%) in hippocampus. L-NAME administration increased NFκB levels caused by CCAO in hippocampus and decreased ERKp1/2 (-46.70% ± 5.14%), NGF (-44.13% ± 0.21%) and EGFR (-40.00% ±1.73%) without affecting iNOS, eNOS, SDF and BDNF as compare with the control groups. L-NAME prevented the loss of long-term memory caused by CCAO, but decreased the number of crossing by platform space. Conclusion. Nitric oxide inhibition by nNOS decreased the growth factors involved in long-term memory retention. Topic: Disorders and nervous system repair


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VOLTAGE-DEPENDENT ANION CHANNEL IS PART OF ANEUROTOXIC MECHANISMS AND ALZHEIMER’S DISEASE’S PROGRESSION R. Marin 1, A. Canerina-Amaro1, M. Gonzalez-Gomez1, I. Ferrer2, M. Diaz3 1 . Laboratory of Cellular Neurobiology, Department of Basic Medical Sciences, Medicine, Faculty of Health Sciences, University of La Laguna, Tenerife 2 . Institute of Neuropathology, Bellvitge University Hospital, University of Barcelona, IDIBELL, CIBERNED, Hospitalet de Llobregat, Barcelona 3 . Laboratory of Membrane Physiology and Biophysics, Department of Animal Biology, Edaphology and Geology, University of La Laguna, Tenerife

Voltage-dependent anion channel (VDAC) is a mitochondrial porin abundantly found in neuronal lipid raft microdomains, where it is associated in signaling platforms to trigger neuroprotective/neurotoxic responses. Loss of lipid integrity in these microdomains alters protein complexes, promoting VDAC opening, ultimately leading to neuronal death (Marin et al., Neuroscience 2013; 2104). Our previous data has demonstrated the abundance of VDAC surrounding senile plaques, as a hallmark of VDAC involvement in AD pathology. Moreover, VDAC has been shown as part of multimeric signalosomes found in lipid rafts, which are involved in neuroprotective/neurotoxic signaling via modulation of VDAC phosphorylation state. Using human frontal cortex of AD patients of, both, early and late stages (ADI/III and ADV/VI) agematched with healthy controls, as well as human cultured cells, we have demonstrated that VDAC is involved in A-induced neurotoxicity. For lipid and protein dynamic analyses, experiments were performed by lipid raft isolation, liquid chromatography, ELISA, immunoblotting, immunoprecipitation, immunochemistry and confocal microscopy techniques. In neuronal lipid rafts, VDAC was associated with the amyloid precursor protein (APP) since ADI/II stages, thereby promoting A promoting and aggregation. Furthermore, A enhanced VDAC dephosphorylation in correlation with cell death. Channel modulation was corroborated in lipid rafts of cortical regions in AD brains. We also analyzed the potential correlation of AD biomarkers, A, tau and P-tau with VDAC presence in the cerebrospinal fluid of AD patients, observing a direct proportion of A/VDAC ratio in these fluid samples (Fabelo et al., Neurobiology Aging 2014; 2017; Marin et al., Current Alzheimer Research, 2017). These results indicate that modulation of VDAC channel through interactions with the different ADrelated actors in neuronal microdomains is a parameter of the development and progression of AD pathology. Indeed, VDAC may be a potential biomarker since early stages of this neuropathology. Grants SAF2014-52582-R from MINECO, and PI14/00757 from ISCIII-FEDER Funds Topic: 6. Disorders and nervous system repair


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EXPLORING GRAPHENE-BASED SUBSTRATES AS NOVEL BIOMATERIALS FOR NEURAL REPAIR IN THE INJURED SPINAL CORD A. Domínguez 1, A. González-Mayorga 1, E. López-Dolado 1, M.C. Serrano 1,2 1 . Hospital Nacional de Parapléjicos, Servicio de Salud de Castilla-La Mancha, Toledo, Spain 2 . Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Científicas, Madrid, Spain

Neural repair at the injured spinal cord continues to be a tremendous challenge for both researchers and clinicians. This type of lesions causes a dramatic change in quality of life and life expectancy of the patients and has a high sanitary burden associated. These aspects, along with its increasing incidence and prevalence are fueling the exploration of novel therapeutic strategies including the use of biomaterials and reparative neural interfaces. Graphene-derived materials show promise for neural repair, even though their toxicity and degradability in vivo are still an open debate. In this study, we investigated the potential utility of 3D scaffolds composed of reduced graphene oxide (rGO) for neural repair. Two types of rGO structures were explored: porous scaffolds and microfibers. Both types of materials were first interfaced with embryonic neural progenitor cells in culture to assess basic biocompatibility aspects in neural networks in vitro. Parameters such as adhesion, morphology and differentiation were studied. Then, rGO biomaterials were implanted in the injured spinal cord of hemisected rats (C6 right hemisections in adult male Wistar rats, n = 31). Treatment groups were: control, injury alone, injury + rGO scaffold, and injury + rGO microfibers. Histological and immunofluorescence studies were carried out at 10, 30 and 120 days to detect fibrotic, inflammatory, angiogenic and regenerative responses. Injured animals without scaffolds showed more cavities and poorly structured lesion zones. Collagen fibers were evident around and inside the rGO biomaterials, which appeared completely infiltrated by cells mainly positive for vimentin and PDGFRβ. Abundant new blood vessels were invading scaffold inner parts, with new axons in their proximities. Macrophages were less and less profuse with time, showing both M1 and M2 phenotypes. Taken together, these results demonstrate the promising potential of rGO-based biomaterials for neural repair in the injured spinal cord and encourage further investigation. This project has received funding from the Instituto de Salud Carlos III-MINECO (CP13/00060, cofunded by FEDER), the Ministerio de Economía, Industria y Competitividad (MAT2016-78857-R; AEI/FEDER, UE) and the European Union's Horizon 2020 research and innovation programme under grant agreement No 737116.


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ACTIVATION OF MEDIUM SPINY NEURONS BY OPTOGENETICS INDUCES DYSKINESIAS IN A PARKINSON DISEASE MODEL

Hernandez LF1,2, Castela I1,2, Ruiz-DeDiego I2,3, Obeso JA1,2, Moratalla R2,3. 1 HM-CINAC, Hospital Universitario HM Puerta del Sur, Móstoles and Medical School, CEU-San Pablo University, Madrid, Spain 2 CIBERNED, Instituto Carlos III, Madrid, Spain 3 Instituto Cajal-CSIC, Madrid, Spain

Long-term levodopa (L-DOPA) treatment is still associated with the development of L-DOPAinduced dyskinesias (LIDs) in the majority of patients with Parkinson disease (PD), which often impairs quality of life and necessitates several therapeutic adjustments. The etiopathogonesis and mechanisms underlying LIDs are not well understood. We used striatal optogenetic stimulation to induce dyskinesias in a hemiparkinsonian model of PD in rats. Striatal dopamine depletion was induced unilaterally by 6-hydroxydopamine (6-OHDA) injection into the medial forebrain bundle. For the optogenetic manipulation, we injected AAV viral particles associated to channelrhodopsin (ChR2) for its expression in calmodulin kinase-positive neurons (CAMKII) to stimulate striatal medium spiny neurons with a blue laser. Simultaneous optical activation of medium spiny neurons (MSNs) of the direct and indirect striatal pathways in the dopamine depleted side induced abnormal movements similar to LIDs, labeled here as optodyskinesias. Noticeably, optodyskinesias were facilitated by L-DOPA in animals that did not respond initially to the laser stimulation. Post-mortem tissue analysis revealed increased FosB expression, a molecular marker of LIDs, primarily in MSNs of the direct pathway exclusively in the dopamine depleted hemisphere. Here we show that generation of LIDs is not associated with opposite physiological activity of the direct and indirect pathways. Moreover, the optogenetic activation of the dorsolateral striatum suggests that this abnormal activation, despite being exclusive from the dopamine depletion state, is independent of dopamine receptor involvement. Altogether, these results are a potential breakthrough in understanding the mechanisms and pathways involved in striatal induced abnormal movement.


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GENERALIZED AXONAL EXCITABILITY DEFICITS UNDERLIE THE DEVELOPMENTAL ONSET OF MOTOR ABNORMALITIES AND REPETITIVE BEHAVIORS IN CNTNAP2 MUTANT MICE

A Sánchez-Aguilera1,2, R Scott3, K van Elst4, L Lim1,2, N Dehorter1, SE Bae1,2, G Bartolini1,3, E Peles5, H Bruining4, MJH Kas4,6, O Marín1,2,3 1 Centre for Developmental Neurobiology, King’s College London, London, United Kingdom 2 MRC Centre for Neurodevelopmental Disorders, King’s College London, London, United Kingdom 3 Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas & Universidad Miguel Hernández, Alicante, Spain 4 Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, The Netherlands 5 Weizmann Institute of Science, Rehovot 7610001, Israel 6 Groningen Institute for Evolutionary Life Sciences, University of Groningen, The Netherlands

Genetic variation in CNTNAP2 has been linked to several neurological and neuropsychiatric conditions such as childhood apraxia of speech and language impairments, intellectual disability, autism spectrum disorder (ASD), epilepsy and schizophrenia. Previous work has suggested that Cntnap2 mutant mice display many features observed in humans carrying homozygous mutations in CNTNAP2, including epilepsy, abnormal social behavior and communication defects. However, the cellular and molecular mechanisms underlying these deficits are not fully understood. Here, we found that Cntnap2 mutant mice are characterized by abnormal motor behaviour and stereotypies, defects that have an onset between 4 and 6 weeks of postnatal age. These deficits are not linked to a decrease in the number of cortical interneurons or impairment of the inhibition received by cortical pyramidal neurons. In contrast, myelinated axons in the cortex of Cntnap2 mutant mice have defects in the clustering of Kv1.2 channels in the juxtaparanodal region of the nodes of Ranvier. This defect perturbs the waveform of action potentials in long-range axons across the corpus callosum, which leads to an increase in the amplitude of excitatory synaptic responses in layer 2/3 pyramidal cells. We also found that myelination is delayed in the cortex of Cntnap2 mutant mice, which may influence the timing of onset for behavioural abnormalities. The generalized defects in long-range axonal communication caused by the loss of Cntnap2 reveals a pervasive mechanism through which pathological variation in human CNTNAP2 may predispose to multiple neurodevelopmental disorders. Topic: 6. Disorders and nervous system repair


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CHARACTERIZATION OF INTRACELLULAR MECHANISMS INVOLVED IN THE SHORT- AND LONG- TIMES EFFECTS OF GDNF IN PRIMARY CULTURES OF MESENCEPHALIC NEURONS OF RAT V. Mesa-Infante1 F. Fumagallo1,2,3, J. Salas-Hernández1, J. López Fernández1, D. Afonso Oramas1,2,3 , T. González Hernández 1,2,3,4, P. Barroso-Chinea 1,2,3 1 Departamento de Ciencias Médicas Básicas (Anatomía), Facultad de Ciencias de la Salud (Medicina), Universidad de La Laguna, Tenerife, Spain. 2 Centro de Investigaciones Biomédicas de Canarias (CIBICAN), Tenerife, Spain. 3 Instituto Universitario de Tecnologías Biomédicas (ITB), Tenerife, Spain. 4 Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas, Instituto de Salud Carlos III.

The glial derived neurotrophic factor (GDNF) promotes differentiation, proliferation and survival in different cell types, including dopaminergic neurons. So, GDNF has been proposed as a neuroprotective therapy in Parkinson's disease (PD). Although findings coming from cellular and animals models of PD are promising, those arising from clinical trials are not as good as expected, due probably to the use of inappropriate administration protocols. In spite of the increasing information about the action mechanisms of GDNF, many aspects about its pharmacological effects remain unclear and data from different studies are contradictory. Subject: Bearing in mind that GDNF actions are mediated by its tyrosine kinase receptor RET that activates the PI3K/AKT and MAPK/ERK signalling pathways, it would be interesting to study the effect of GDNF, in short and long times, on the regulation of the PI3K/AKT and MAPK/ERK signaling pathways by RET in mesencephalic dopaminergic neurons of rat. Material and methods: midbrain cell cultures of rat were treated with GDNF at different doses (0.3, 1 and 10 ng/ml) and times (15 minutes, 24 hours and 7 days). Western blot was performed to detect the expression levels (total and phosphorylated) of RET, AKT, ERK1/2, GSK3β, S6 ribosomal, and tyrosine hydroxylase (TH, the limiting enzyme in DA synthesis), after GDNF treatment. Results: Acute GDNF treatment induces a transient increase in RET, AKT, ERK1/2, S6 and GSK3β phosphorylation as well as of TH expression levels. However, after prolonged GDNF treatment the phosphorylation level of these kinases and TH expression decline below basal levels. Conclusion: The findings suggest that prolonged GDNF treatment desensitizes but also inhibits the receptor, making it likely that dopaminergic neurons are more vulnerable to degeneration. Supported by: BFU2013-47242-R, BFU2016-77363-R and IMBRAIN project (FP7-REGPOT-2012CT2012-31637- IMBRAIN). Áreas Temáticas: 1ª: Trastornos y reparación del sistema nervioso 2ª: Neurociencia de sistemas


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TRANSCRANIAL MAGNETIC STIMULATION AMELIORATES OXIDATIVE STRESS CAUSED BY EXPERIMENTAL AUTOIMMUNE ENCEPHALOMYELITIS

F.J. Medina-Fernández1,2, E. Agüera2,3, C. Conde3, E. Luque4,2, M. LaTorre1,2, A.I. Giraldo1,2, M. Feijóo1, F. Gascón2,5, R. Lillo2,6, A. Galván1,2, A. Ropero1,2 B.M. Escribano2,7, I. Túnez1,2 1 Departamento de Bioquímica y Biología Molecular, Facultad de Medicina y Enfermería, Universidad de Córdoba, Córdoba, Spain. 2 Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Córdoba, Spain 3 Unidad de Gestión Clínica de Neurología, Hospital Universitario Reina Sofía, Córdoba, Spain 4 Sección de Histología, Departamento de Ciencias Morfológicas, Facultad de Medicina y Enfermería, Universidad de Córdoba, Córdoba, Spain 5 Unidad de Gestión Clínica de Análisis Clínicos, Hospital Comarcal Valle de los Pedroches, Córdoba, Spain 6 Sección de Psiquiatría, Departamento de Ciencias Sociosanitarias y Radiología Clínica y Medicina Física, Facultad de Medicina y Enfermería, Universidad de Córdoba, Córdoba, Spain 7 Sección de Fisiología, Departamento de Biología Celular, Fisiología e Inmunología, Facultad de Veterinaria, Universidad de Córdoba, Córdoba, Spain

Background Multiple sclerosis is a chronic neuro-inflammatory disease. At the present day is necessary to look for new therapeutic strategies and treatments. Experimental autoimmune encephalomyelitis (EAE) is the most important animal experimental model for studying of multiple sclerosis. Objective The aim of this work was evaluating the neuroprotective effect and oxidative stress of transcranial magnetic stimulation (TMS) from two different approaches: Evaluation of the clinical score. Quantification of biochemical biomarkers of oxidative stress: Lipid peroxidation products (LPPs) and lipopolysaccharide binding protein (LPB). Material and methods The study was carried out with 35 Dark Agouti male rats, divided in 5 groups: i) Healthy animals (controls), ii) Animals treated Freund's adjuvant (vehicle controls), iii) Animals inoculated with MOG (EAE), iv) EAE treated with Mock (EAE + Mock), v) EAE plus transcranial magnetic stimulation treated (EAE + TMS). EAE was induced by subcutaneous injection of an emulsion containing myelin oligodendrocyte glycoprotein (MOG), phosphate-buffered saline (PBS), Freund’s adjuvant and inactivated Mycobacterium tuberculosis. Clinical score was determined 14 and 35 days after injection of MOG. Oxidative stress was evaluated by lipid peroxidation products (LPPs); whereas the possible dysbiosis was determined by LPS levels. Results Our data also shows that TMS treatment reduces the oxidative stress damage in brain and spinal cord, as LPO and LPS levels exhibit a significant decrease after TMS treatment. Conclusions TMS effectively decreases motor dysfunction caused by EAE, reversing towards normality the clinical score. References Escribano B, Medina-Fernandez FJ, Aguilar-Luque M. et al. Lipopolysaccharide Binding Protein and Oxidative Stress in a Multiple Sclerosis Model.Neurotherapeutics (2017) 14 (1):199-211. Medina-Fernandez FJ, Luque E, Aguilar-Luque M. et al. Transcranial magnetic stimulation modifies astrocytosis, cell density and lupopolysaccharide levels in experimental autoinmune encephalomyelitis (2017) 15;169:20-26.


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GENE THERAPY FOR DRAVET SYNDROME: A PROOF OF CONCEPT

A. Ricobaraza1, M. Valencia 1, M. González-Aparicio1, M.J. Nicolás1, S. Arrieta1, M. Buñuales1, E. Puerta2, R. Sánchez-Carpintero3,4, G. González-Aseguinolaza1, J. Artieda3 and R. Hernández-Alcoceba1 1 . Center for Applied Medical Research (CIMA), University of Navarra, Pamplona, Navarra, Spain. 2 . University of Navarra, Pamplona, Navarra, Spain. 3 . Clínica Universidad de Navarra, Pamplona, Spain. 4 . Navarra Health Research Institute (IDISNA), Pamplona, Navarra, Spain.

Dravet syndrome (DS) is a severe epileptic encephalopathy with infantile onset, characterized by refractory seizures, increased risk of sudden death, as well as mental, behavioral and motor comorbidities. In most cases, the genetic basis is a haploinsufficiency caused by mutations in SCN1A, which encodes the alpha subunit of a voltage-dependent Na+ channel (Nav1.1). Due to the complex physiopathology of DS, etiological approaches such as gene therapy have unique chances to obtain a global improvement in the life of these patients. We aim to deliver a functional copy of the SCN1A gene to the brain using High-Capacity adenoviral vectors (HC-Ad). To provide proof of concept about the feasibility of this approach we generated a preliminary vector prototype carrying a codon-optimized SCN1A cDNA under the control of a ubiquitous promoter sequence (CAG). The expression cassette inserted into the vector genome was stable in E.Coli and gave rise to viable HCAd particles following a standard rescue and amplification protocol. The resulting HCA-CAGSCN1A vector was able to infect neurons and increase the amount of Nav1.1 in a dose-dependent manner. Biodistribution analysis using HC-Ad vectors encoding GFP demonstrated efficient transduction of neurons upon intracerebral administration. Finally, in vitro luciferase reporter assays were performed to select a regulatory sequence with preferential activity in GABAergic/paravalbumin-expressing inhibitory neurons. In summary, the results obtained so far indicate that gene therapy based on HC-Ad vectors is a viable option for the treatment of DS. Topic: Disorders and nervous system repair


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CHANGES IN THE LEVELS OF LOW DENSITY LIPOPROTEIN RECEPTOR-RELATED PROTEIN (LRPs) IN SCHIZOPHRENIA

M. Blanco-Formoso1, T. Rivera-Baltanás T1,3, MC. Vallejo-Curto1,2, G. Cabo-Escribano1,2, DS. Rodrigues-Amorim1, RC. Agís-Balboa1,2,3, E de las Heras-Liñero1, 2, 3, A. Núñez-Torrón2, JM. Olivares1,2,3, C. Spuch1,3 1 . Galicia Sur Health Research Institute (IIS Galicia Sur). Vigo (Spain). 2 . Álvaro Cunqueiro Hospital (SERGAS). Vigo (Spain). 3 . CIBER de Salud Mental (CIBERSAM).

Background The cellular microenviroment is emerging as a critical regulator in chronic mental disorders. Regulated intramembrane proteolysis (RIP) is a highly conserved signaling pathway whereby membrane-bound signaling proteins are cleaved in their transmembrane region and then released into the cytoplasm to act as signaling molecules. In most, if not all cases, intramembrane cleavage is preceded and regulated by a membrane proximal cleavage step called “ectodomain shedding”. The properties of the shedding process could induce the molecular changes in soluble receptors released to the extracellular matrix. The side effect of this profile expression and activities could be determined through quantifying some of these soluble receptors. The role of RIP ectodomain shedding in LRP signaling pathway, is a highly conserved cell-cell communication pathway that mediates cell fate decisions during development and in adult tissues. Metalloproteinases (MMPs) and a disintegrin and metalloproteinases (ADAMs) cleave the receptor releasing the extracellular domain (ECD) and intracellular domain (ICD). Here, we will analyze the changes of different soluble fragments derived from LRPs receptors in the serum of schizophrenic patients. Material and methods: We collected blood samples from 39 patients with first-episode schizophrenia while 27 healthy individuals were enrolled. Psychopathological severity were assessed using the Positive and Negative Syndrome Scale (PANSS). We measured the levels of sLRP4, sLRP5, sLRP6 and sLRP8 in serum by ELISA kits. Results: Lower levels of sLRP8 (Reelin receptor) (p