TMS is a non-invasive treatment where magnetic pulses are delivered to stimulate nerve cells in the part of the brain controlling the mood, which is often underactive in patients with depression. Repeated stimulation of this part of the brain has proven to produce an antidepressant effect on people suffering from depression. TMS is also known as rTMS (repetitive transcranial magnetic stimulation) because more than one magnetic pulse is delivered to the brain during a treatment session.