Patients with recent-onset Schizophrenia show alterations in N100, N170 and P200 ERPs
No:
15
Arun Sasidharana,c, Ajay Kumar Naira,c, John P Johnb,c,d, Bindu M Kuttya aDepartment
of Neurophysiology, bDepartment of Psychiatry, cMultimodal Brain Image Analysis Laboratory (MBIAL), dDepartment of Clinical Neurosciences, National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru, India
~26yrs of age
Controls
n=21
7 14
Schizophrenia 9-Drug Naive; 3-Drug free; ~3yrs illness
(Psychology Software Tools, USA)
(Neuroscan-Compumedics, USA)
45 min preparation time 45-60 min task time 3-Levels; 48 Blocks; 1200 Trials LCD monitor + Headphone + mouse
64 EEG electrode cap 4 EOG electrodes 24-bits resolution; 1000Hz sampling rate 0.1-100Hz hardware filter
Stimulus presention & EEG acquisition
EEG monitoring & analysis
Subject: Venkataramappa, Age: 39 EEG file: AS_CNT_24_Madhusudhanan_22Jul2013_Who_reref.cnt Recorded : 16:36:23 22-Jul-2013 Rate - 1000 Hz, HPF - 0.05 Hz, LPF - 100 Hz, Notch - off, Montage - None
FZF2FCZFC2C3-
3 Conditions
Control Schizophrenia
Altered ERP (N100-P200 complex) in Schizophrenia
Neuroscan SCAN 4.5 Printed : 15:50:08 30-Sep-2013
F1-
GESTALT PERCEPTION TASK
Control vs Schizophrenia
-
ANALYSIS
TASKS
Control vs Schizophrenia
Schizophrenia
Synamps2 70 channel EEG-ERP system
Reduced ERSP dynamics (beta & gamma power) in Schizophrenia
Control
E-Prime 2 Presentation Software
Grey band indicates significant difference
GESTALT PERCEPTION TASK
n=24
9 15
Reduced ERP (N170-P200 complex) in Schizophrenia
Schizophrenia
METHODS
RESULTS & DISCUSSION
Control
INTRODUCTION o Schizophrenia is characterized by psychotic symptoms that are believed to be caused by a basic inability to make valid predictions about expected sensations and experiences. o These have been reported separately while monitoring either externallygenerated environmental patterns (e.g. gestalt perception) or selfgenerated sensory experiences (e.g. corollary discharge). o We evaluated the abnormalities of prediction during a simultaneous gestalt perception and corollary discharge task among patients with schizophrenia.
Grey band indicates significant difference
C1CZC2-
Altered ERSP dynamics (beta & gamma power) in Schizophrenia
C4M1CP3CPZ-
P3-
Face/Triangle absent condition
Baseline condition
P4+64 µV CB1600 ms
OZ-
235
254 116
246 1
00:01:37
235
254 116
246 1
00:01:38
235
00:01:39
254 116
246 1
00:01:40
Subject: Venkataramappa, Age: 39 EEG file: AS_CNT_24_Madhusudhanan_22Jul2013_Who_reref.cnt Recorded : 16:36:23 22-Jul-2013 Rate - 1000 Hz, HPF - 0.05 Hz, LPF - 100 Hz, Notch - off, Montage - None
224
254 116
00:01:41
246
00:01:42
Neuroscan SCAN 4.5 Printed : 15:51:43 30-Sep-2013
F1FZF2FCZFC2C3C1CZC2C4M1-
M2-
COROLLARY DISCHARGE TASK
P3P2P4+64 µV CB1600 ms
OZ-
3 Conditions
235
254 116
246 1
00:01:37
1500 ms
Press-Tone condition
Only Tone condition
235
254 116
246 1
00:01:38
235
00:01:39
1500 ms
254 116
246 1
00:01:40
1500 ms
Subject: Venkataramappa, Age: 39 EEG file: AS_CNT_24_Madhusudhanan_22Jul2013_Who_reref.cnt Recorded : 16:36:23 22-Jul-2013 Rate - 1000 Hz, HPF - 0.05 Hz, LPF - 100 Hz, Notch - off, Montage - None
Only Press condition
224
254 116
00:01:41
246
00:01:42
1500 ms Neuroscan SCAN 4.5 Printed : 15:51:43 30-Sep-2013
F1FZF2FCZFC2C3C1CZC2C4-
CP3CPZM2P3P2P4+64 µV
Control vs Schizophrenia
Control
M1-
Control vs Schizophrenia
Schizophrenia
CP3CPZ-
COROLLARY DISCHARGE TASK
Face/Triangle Present condition
P2-
Control
Control Schizophrenia
M2-
CB1600 ms
OZ-
235
254 116
246 1
00:01:37
235
00:01:38
254 116
246 1
235
00:01:39
254 116
246 1
00:01:40
224
00:01:41
254 116
246
-
00:01:42
Schizophrenia
using EEGLAB toolbox of MATLAB-2012b (Mathworks, USA)
o Event-related changes in the EEG potentials (ERP): by averaging EEG segments
CONCLUSION
Event onset
o Event-related changes in the power of various EEG frequency spectra (ERSP): using Wavelet analysis on EEG segments Statistical Analysis: Between group comparisons done using Permutation test on each time point data followed by FDR correction (alpha < 0.01) [implemented in EEGLAB toolbox of MATLAB-2012b (Mathworks, USA)]
The findings of the study reveal the possibility of a fundamental deficit in brain synchronizing mechanisms resulting in impaired predictive mechanisms in schizophrenia. Further studies are warranted to elucidate the pathophysiological mechanisms of aberrant brain synchrony in schizophrenia causing abnormal behaviour.
ACKNOWLEDGEMENTS and REFERENCES We thank Ms. Ammu Lukose for help in subject recruitment. We acknowledge funding from Indian Council for Medical Research (Fellowship to A.S.; Grant No:55/2/2012-BMS to B.M.K., SRF to A.K.N.), and Department of Science and Technology (Grant No.SR/CSI/79/2010 to J.P.J.). Ref: 1)Ford JM, Mathalon DH. Electrophysiological evidence of corollary discharge dysfunction in schizophrenia during talking and thinking. J Psychiatr Res 2004; 38: 37-46. 2)Uhlhaas PJ, Linden DE, Singer W, et al. Dysfunctional long-range coordination of neural activity during Gestalt perception in schizophrenia. J Neurosci 2006; 26:8168–8175.
International Symposium on Translational Neuroscience & XXXII Annual Conference of Indian Academy of Neurosciences (IAN-2014) held at NIMHANS, Bengaluru, Karnataka.
Contact:
[email protected]
