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Influence of transcranial alternating current stimulation on brain oscillations:an EEG based study. Davide Cappon1, Anahita Goljahani2, Patrizia Bisiacchi1 1Department of General Psychology “Vittorio Benussi”,via Venezia 8 ,35131 , University of Padova, Italy. 2Department of Information Engineering,via G. Gradenigo6/b, University of Padova, Italy.
Introduction Recently transcranial alternating current stimulation ( tACS ) has emerged as a new technique of non-invasive brain stimulation able to interact with neuronal oscillations. A growing number of studies showing the effectiveness of tACS activity in modulating sensory, motor and even higher cognitive processing (Hermann et al 2013,Vossen et al 2015).In our previous study we demonstrate the frequency specific effects of tACS on automatic motor control (Cappon et al 2016). However, the neurophysiological mechanisms of tACS are still poorly understood. This study aims at investigating the interactions between tACS and rhythmic EEG activities by assessing to what extent stimulations at 10 and 20 Hz cause changes in alpha power and how these changes are distributed on the scalp.
Results 60.00
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ERS/ERD (8-13) 50.00
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* 10Hz 30.00
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sham
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** 10Hz
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20Hz 35.00
sham
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25.00 10.00 20.00
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Eight healthy volunteers (4females, 22-33, mean age = 27 age years) participated in the experiment. Based on our prior study (Cappon et al. 2016) stimulation was delivered at alpha (10 Hz) and beta (20 Hz) frequency over the area of the scalp corresponding to the electrodes Fz , F2 , FCZ , FC2 and C3 , C5 , CP5 , CP3. Immediately before and after the stimulation EEG data were collected by 52 active electrodes. For each electrode, increase/decrease of power in the alpha band, (8, 13) Hz, was computed by means of the power spectral density (PSD) approach implemented in the Channel Reactivity Based (CRB) toolbox (Goljahani et al 2012, 2014). Similarly to the well established Event - Realated Synchronization / desynchronization ( ERS / ERD ) index (Pfurtscheller, & Lopes da Silva, 1999), changes in power were expressed as percentual relative variations and were denoted as ERS/ERD.
Anova with factors stimulation (10Hz,20Hz,sham) and location(1,2,3,4,5,6,7) reveal a significant interaction stimulatoin * location on ERS/ERD F(8)=3.844 , p-value:
