Transcranial magnetic stimulation (TMS) is a form of neurostimulation. TMS is a non-invasive procedure in which a changing magnetic field is used to cause electric current to flow in a small targeted region of the brain via electromagnetic induction. During a TMS procedure, a magnetic field generator, or "coil", is placed on the scalp. The coil is connected to a pulse generator, or stimulator, that delivers a changing electric current to the coil.