Transcranial Electric Stimulation

Transcranial Electric Stimulation, direct, alternating, or random noise (tDCS, tACS, tRNS) involves application of current/ voltage to two or more surface electrodes, with at least one of them placed on the scalp. The current from the waveform generator passes through the solid conductor, the electrolyte, and the skin to enter or exit the body. The electric and current density fields injected in the tissues are directly proportional to the current entering the body. Transcranial electric stimulators have current-controlled output, meaning that the electrode current is controlled to follow the waveform characteristics programmed in the device (e.g., square current pulses with a set amplitude, pulse width, frequency, etc.)