AUTHOR=Holzmann Romain , Koppehele-Gossel Judith , Voss Ursula , Klimke Ansgar TITLE=Investigating Nuisance Effects Induced in EEG During tACS Application JOURNAL=Frontiers in Human Neuroscience VOLUME=15 YEAR=2021 URL=https://www.frontiersin.org/journals/human-neuroscience/articles/10.3389/fnhum.2021.637080 DOI=10.3389/fnhum.2021.637080 ISSN=1662-5161 ABSTRACT=

Transcranial alternating-current stimulation (tACS) in the frequency range of 1–100 Hz has come to be used routinely in electroencephalogram (EEG) studies of brain function through entrainment of neuronal oscillations. It turned out, however, to be highly non-trivial to remove the strong stimulation signal, including its harmonic and non-harmonic distortions, as well as various induced higher-order artifacts from the EEG data recorded during the stimulation. In this paper, we discuss some of the problems encountered and present methodological approaches aimed at overcoming them. To illustrate the mechanisms of artifact induction and the proposed removal strategies, we use data obtained with the help of a schematic demonstrator setup as well as human-subject data.