Concurrent electroencephalography recording during transcranial alternating current stimulation (tACS)

Fehér, Daniel Kristoffer; Morishima, Yosuke (2016). Concurrent electroencephalography recording during transcranial alternating current stimulation (tACS). Journal of visualized experiments, 107(107), e53527. MYJoVE Corporation 10.3791/53527

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Oscillatory brain activities are considered to reflect the basis of rhythmic changes in transmission efficacy across brain networks and are assumed to integrate cognitive neural processes. Transcranial alternating current stimulation (tACS) holds the promise to elucidate the causal link between specific frequencies of oscillatory brain activity and cognitive processes. Simultaneous electroencephalography (EEG) recording during tACS would offer an opportunity to directly explore immediate neurophysiological effects of tACS. However, it is not trivial to measure EEG signals during tACS, as tACS creates a huge artifact in EEG data. Here we explain how to set up concurrent tACS-EEG experiments. Two necessary considerations for successful EEG recording while applying tACS are highlighted. First, bridging of the tACS and EEG electrodes via leaking EEG gel immediately saturates the EEG amplifier. To avoid bridging via gel, the viscosity of the EEG gel is the most important parameter. The EEG gel must be viscous to avoid bridging, but at the same time sufficiently fluid to create contact between the tACS electrode and the scalp. Second, due to the large amplitude of the tACS artifact, it is important to consider using an EEG system with a high resolution analog-to-digital (A/D) converter. In particular, the magnitude of the tACS artifact can exceed 100 mV at the vicinity of a stimulation electrode when 1 mA tACS is applied. The resolution of the A/D converter is of importance to measure good quality EEG data from the vicinity of the stimulation site. By following these guidelines for the procedures and technical considerations, successful concurrent EEG recording during tACS will be realized.

Item Type:

Journal Article (Further Contribution)


04 Faculty of Medicine > University Psychiatric Services > University Hospital of Psychiatry and Psychotherapy > Translational Research Center

Graduate School:

Graduate School for Health Sciences (GHS)

UniBE Contributor:

Fehér, Daniel Kristoffer, Morishima, Yosuke


600 Technology > 610 Medicine & health




MYJoVE Corporation




Yosuke Morishima

Date Deposited:

15 Feb 2017 15:41

Last Modified:

02 Mar 2023 23:28

Publisher DOI:


PubMed ID:





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