title: Eyes wide shut: Transcranial alternating current stimulation drives alpha rhythm in a state dependent manner.
abstract: Transcranial alternating current stimulation (tACS) is used to modulate brain oscillations to measure changes in cognitive function. It is only since recently that brain activity in human subjects during tACS can be investigated. The present study aims to investigate the phase relationship between the external tACS signal and concurrent brain activity. Subjects were stimulated with tACS at individual alpha frequency during eyes open and eyes closed resting states. Electrodes were placed at Cz and Oz, which should affect parieto-occipital areas most strongly. Source space magnetoencephalography (MEG) data were used to estimate phase coherence between tACS and brain activity. Phase coherence was significantly increased in areas in the occipital pole in eyes open resting state only. The lag between tACS and brain responses showed considerable inter-individual variability. In conclusion, tACS at individual alpha frequency entrains brain activity in visual cortices. Interestingly, this effect is state dependent and is clearly observed with eyes open but only to a lesser extent with eyes closed.
authors.affiliation: Center for Mind/Brain Sciences, University of Trento, via delle Regole 101, 38123 Mattarello, Italy.|Centre for Cognitive Neuroscience, University of Salzburg, Hellbrunnerstraße 34, 5020 Salzburg, Austria.
authors.forename: Philipp
authors.initials: P
authors.lastname: Ruhnau
authors.affiliation: Center for Mind/Brain Sciences, University of Trento, via delle Regole 101, 38123 Mattarello, Italy.|Centre for Cognitive Neuroscience, University of Salzburg, Hellbrunnerstraße 34, 5020 Salzburg, Austria.
authors.forename: Toralf
authors.initials: T
authors.lastname: Neuling
authors.affiliation: Center for Mind/Brain Sciences, University of Trento, via delle Regole 101, 38123 Mattarello, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Fuscá
authors.affiliation: Experimental Psychology Lab, Center for Excellence "Hearing4all," European Medical School, University of Oldenburg, 26111 Oldenburg, Germany.|Research Center Neurosensory Science, University of Oldenburg, Carl-von-Ossietzky-Strasse 9-11, 26129 Oldenburg, Germany.
authors.forename: Christoph S
authors.initials: CS
authors.lastname: Herrmann
authors.affiliation: Center for Mind/Brain Sciences, University of Trento, via delle Regole 101, 38123 Mattarello, Italy.|Centre for Cognitive Neuroscience, University of Salzburg, Hellbrunnerstraße 34, 5020 Salzburg, Austria.
authors.forename: Gianpaolo
authors.initials: G
authors.lastname: Demarchi
authors.affiliation: Center for Mind/Brain Sciences, University of Trento, via delle Regole 101, 38123 Mattarello, Italy.|Centre for Cognitive Neuroscience, University of Salzburg, Hellbrunnerstraße 34, 5020 Salzburg, Austria.
authors.forename: Nathan
authors.initials: N
authors.lastname: Weisz
mesh_terms: D000328:Adult; D000513:Alpha Rhythm / Q000502:physiology*; D001931:Brain Mapping; D003071:Cognition / Q000502:physiology; D005260:Female; D006801:Humans; D015225:Magnetoencephalography; D008297:Male; D009799:Ocular Physiological Phenomena; D065908:Transcranial Direct Current Stimulation / Q000379:methods*; D014793:Visual Cortex / Q000502:physiology*