Transcranial magnetic stimulation
Transcranial magnetic stimulation (TMS) is a noninvasive neurostimulation technique in which a changing magnetic field is used to induce an electric current in a targeted area of the brain through electromagnetic induction. A device called a stimulator generates electric pulses that are delivered to a magnetic coil placed against the scalp.
Source: Wikipedia — Transcranial magnetic stimulation (CC BY-SA 4.0)