Journal Title: Frontiers in Human Neuroscience
ISSN: 1662-5161 (Online)
Publisher: Frontiers Media S.A.
LCC Subject Category: Medicine: Internal medicine: Neurosciences. Biological psychiatry. Neuropsychiatry
Country of publisher: Switzerland
Language of fulltext: English
Full-text formats available: PDF, HTML, ePUB, XML
Philipp eRuhnau (University of Salzburg)
Philipp eRuhnau (Università degli Studi di Trento)
Christian eKeitel (University of Glasgow)
Chrysa eLithari (University of Salzburg)
Nathan eWeisz (University of Salzburg)
Toralf eNeuling (University of Salzburg)
Abstract | Full Text
We tested a novel combination of two neuro-stimulation techniques, transcranial alternating current stimulation (tACS) and frequency tagging, that promises powerful paradigms to study the causal role of rhythmic brain activity in perception and cognition. Participants viewed a stimulus flickering at 7 or 11 Hz that elicited periodic brain activity, termed steady-state responses (SSRs), at the same temporal frequency and its higher order harmonics. Further, they received simultaneous transcranial alternating current stimulation (tACS) at 7 or 11 Hz that either matched or differed from the flicker frequency. Sham tACS served as a control condition. Recent advances in reconstructing cortical sources of oscillatory activity allowed us to measure SSRs during concurrent tACS, which is known to impose strong artifacts in magnetoencephalographic (MEG) recordings. For the first time, we were thus able to demonstrate immediate effects of tACS on SSR-indexed early visual processing. Our data suggest that tACS effects are largely frequency-specific and reveal a characteristic pattern of differential influences on the harmonic constituents of SSRs.