Probing the causal role of prestimulus interregional synchrony for perceptual integration via tACS.
The phase of prestimulus oscillations at 7-10 Hz has been shown to modulate perception of briefly presented visual stimuli. Specifically, a recent combined EEG-fMRI study suggested that a prestimulus oscillation at around 7 Hz represents open and closed windows for perceptual integration by modulating connectivity between lower order occipital and higher order parietal brain regions. We here utilized brief event-related transcranial alternating current stimulation (tACS) to specifically modulate this prestimulus 7 Hz oscillation, and the synchrony between parietal and occipital brain regions. To this end we tested for a causal role of this particular prestimulus oscillation for perceptual integration. The EEG was acquired at the same time allowing us to investigate frequency specific after effects phase-locked to stimulation offset. On a behavioural level our results suggest that tACS did modulate perceptual integration, however, in an unexpected manner. On an electrophysiological level our results suggest that brief tACS does induce oscillatory entrainment, as visible in frequency specific activity phase-locked to stimulation offset. Together, our results do not strongly support a causal role of prestimulus 7 Hz oscillations for perceptual integration. However, our results suggest that brief tACS is capable of modulating oscillatory activity in a temporally sensitive manner.
Vilnius University (Department of Neurobiology and Biophysics) 3 Universiteto St, Vilnius, LT-01513, Lithuania.|University of Birmingham (School of Psychology) Edgbaston, Birmingham, B15 2TT, United Kingdom.
Rolandas
R
Stonkus
University of Birmingham (School of Psychology) Edgbaston, Birmingham, B15 2TT, United Kingdom.
Verena
V
Braun
University of Birmingham (School of Psychology) Edgbaston, Birmingham, B15 2TT, United Kingdom.
Jess R
JR
Kerlin
University of Regensburg (Department of Experimental Psychology) Universitätsstraße 31, Regensburg, 93040, Germany.
Gregor
G
Volberg
University of Birmingham (School of Psychology) Edgbaston, Birmingham, B15 2TT, United Kingdom.
Simon
S
Hanslmayr
D000328:Adult; D058256:Brain Waves; D002540:Cerebral Cortex / Q000502:physiology*; D003344:Cortical Synchronization; D004569:Electroencephalography; D005260:Female; D006801:Humans; D008297:Male; D010775:Photic Stimulation; D065908:Transcranial Direct Current Stimulation; D014796:Visual Perception / Q000502:physiology*; D055815:Young Adult