| Abstract/Results: | ABSTRACT:
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. However, the neurophysiological mechanisms of tACS are still poorly understood . Given the known electroencephalographic (EEG) correlations with clinical conditions , motor processes, cognitive performance, processing of stimuli , etc., this study aims to investigate the interactions between tACS and rhythmic EEG activities by measuring the frequencies involved, changes of power and of their location on the scalp. Based on our prior study, 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. EEG data were analyzed by recent approach Channel Reactivity Based ( CRB ) and established techniques of quantification of changes in power , eg , the Event- Realated Synchronization / desynchronization ( ERS / ERD ). Preliminary results revealed, significant, frequency-dependent changes of power: 10 Hz stimulation specifically increases alpha power t(51)=27,47,p<0.001 but no significant changes in beta and theta power. 20Hz stimulation specifically increases beta power t(51)=2.89,p=0.005,decreases alpha power t(51)=-2.22,p=0.03 no significant changes in theta power. Examination in terms of spatial diffusion is forthcoming.The results provide information on the spectrum of action of the specific stimulation frequencies used.
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