Parkinson's Disease and Gamma-transcranial Alternating Current Stimulation

Transcranial alternating current stimulation (tACS) will be delivered using a BrainSTIM (EMS, Italy) connected to two electrodes (5x5cm) enclosed in sponges soaked with saline solution. One electrode will be centred over the first dorsal interosseus (FDI) hotspot and the other over P3. tACS will be delivered at peak-to-peak amplitude of 1 milliampere (mA), and with 3-seconds ramp-up and down periods. The stimulation frequency will be 70 Hz, as representative of the endogenous motor network-related gamma frequency.

Sham-tACS will consist of ramp-up and down periods and only 1-second stimulation at 1 mA amplitude.