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

Begin with a human participant fitted with a reference transcranial alternating current stimulation (tACS) electrode placed on the shoulder.

Another tACS electrode is positioned on the head with a centrally marked spot.

Pre-applied EEG conductive gel on the head electrode lowers impedance and improves current transmission.

Mount an EEG cap and secure it.

Using a syringe, apply EEG gel to the EEG electrodes to establish contact with the scalp.

Near the tACS site, angle the needle tip away from the tACS electrode to avoid the gel bridging between the tACS and EEG electrodes.

Gently press down the electrodes to avoid gel leakage and monitor the impedance.

Use a wooden stick to compress the gel toward the scalp. This improves electrode contact and further lowers the impedance.

The participant is ready for sinusoidal stimulation via the tACS electrode and simultaneous EEG recording of brain activity.

Gently mount the EEG cap again, and fasten the strap. Apply EEG gel with appropriate viscosity to the EEG electrodes to create contact between the scalp and EEG electrodes.

Begin with the ground and reference EEG electrodes, and then proceed to the electrodes located in the middle and near the tACS e