Establishing Concurrent Transcranial Alternating Current Stimulation and Electroencephalography for Recording Human Brain Activity

Abstract

Source: Fehér, K. D. et. al., Concurrent Electroencephalography Recording During Transcranial Alternating Current Stimulation (tACS). J. Vis. Exp. (2016)

This video demonstrates the setup of concurrent transcranial alternating current stimulation (tACS) and electroencephalography (EEG) experiments to deliver rhythmic electrical signals to the brain while recording brain activity. The procedure ensures electrode isolation and prevents gel bridging for accurate stimulation and clean EEG signals.

Protocol

All procedures involving human participants have been performed in compliance with the institutional, national, and international guidelines for human welfare and have been reviewed by the local institutional review board.

NOTE: Figure 1 illustrates montages and the design of the transcranial alternating current stimulation (tACS) electrodes and electroencephalography (EEG) cap. We use an elastic EEG cap (Figure 1D) to hold the tACS electrode attached to the scalp.

1. Montages

NOTE: The representative results are obtained from the following tACS electrode montages.

1. Montage 1: ....

Results

Figure 1. Illustration of montage. (A) Montage with two tACS electrodes placed on the scalp (.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Stimulator for tACS: Eldith DC-Stimulator plus	NeuroConn GmbH, Germany		For remote input, be sure to order a model with this feature enabled
Analog output board for sending triggers: Static and waveform analog output board, model NI PCI-6723	National Instruments, USA		13-bit, 32 channels.
Matlab and data acquisition toolbox	The MathWorks, Inc., USA		The 'Data acquisition toolbox' available for MATLAB provides functions to control data acquisition hardware such as an analog output board, produced by several manufacturers.
EEG system: eegosports, with a 32 channel waveguard EEG cap	ANT neuro, Netherlands
tACS electrodes	NeuroConn GmbH, Germany	305090-05 305050	Materials: conductive-rubber electrodes.Dimensions of scalp electrodes: Outer Ø: 60 mm, Inner Ø:25 mm (Part# 305090-05) Cut from the original size Ø 75mmDimensions of shoulder electrode:50 x 50 mm (Part# 305050)
EEG gel	Inselspital, Bern, Switzerland		Electrode paste, containing abrasives (i.e. pumice) which scrub the skin, improving the electrode-to-skin contact.
Abrasive skin preparing gel for EEG and electrocardiography: Nuprep	Weaver and Company, USA
Cotton swabs, wooden handle	Salzmann MEDICO, Switzerland		Dimensions:150 x 1.5 mm; wooden handle Ø 2.2 mm
Adhesive tape: Leukofix	BNS medical GmbH, Germany	04.107.12