title: Sustained Aftereffect of α-tACS Lasts Up to 70 min after Stimulation.
abstract: Transcranial alternating current stimulation (tACS) has been repeatedly demonstrated to increase power of endogenous brain oscillations in the range of the stimulated frequency after stimulation. In the alpha band this aftereffect has been shown to persist for at least 30 min. However, in most experiments the aftereffect exceeded the duration of the measurement. Thus, it remains unclear how the effect develops beyond these 30 min and when it decays. The current study aimed to extend existing findings by monitoring the physiological aftereffect of tACS in the alpha range for an extended period of 90 min post-stimulation. To this end participants received either 20 min of tACS or sham stimulation with intensities below their individual sensation threshold at the individual alpha frequency (IAF). Electroencephalogram (EEG) was acquired during 3 min before and 90 min after stimulation. Subjects performed a visual vigilance task during the whole measurement. While the enhanced power in the individual alpha band did not return back to pre-stimulation baseline in the stimulation group, the difference between stimulation and sham diminishes after 70 min due to a natural alpha increase of the sham group.
authors.affiliation: Experimental Psychology Lab, Department of Psychology, European Medical School, Cluster for Excellence "Hearing for All", Carl von Ossietzky University Oldenburg, Germany.
authors.forename: Florian H
authors.initials: FH
authors.lastname: Kasten
authors.affiliation: Experimental Psychology Lab, Department of Psychology, European Medical School, Cluster for Excellence "Hearing for All", Carl von Ossietzky UniversityOldenburg, Germany; German Center for Vertigo and Balance Disorders, Klinikum Grosshadern, Ludwig Maximilian University of MunichMunich, Germany.
authors.forename: James
authors.initials: J
authors.lastname: Dowsett
authors.affiliation: Experimental Psychology Lab, Department of Psychology, European Medical School, Cluster for Excellence "Hearing for All", Carl von Ossietzky UniversityOldenburg, Germany; Research Center Neurosensory Science, Carl von Ossietzky UniversityOldenburg, Germany.
authors.forename: Christoph S
authors.initials: CS
authors.lastname: Herrmann
keywords: EEG; aftereffect; alpha oscillations; transcranial alternating current stimulation (tACS); transcranial electrical stimulation (TES)