rTMS is a non-invasive method of brain stimulation that relies on electromagnetic induction using an insulated coil placed over the scalp, focused on an area of the brain thought to play a role in mood regulation. The coil generates brief magnetic pulses, which pass easily and painlessly through the skull and into the brain. The pulses generated are of the same type and strength as those generated by magnetic resonance imaging (MRI) machines. When these pulses are administered in rapid succession, it is referred to as “repetitive TMS “ or “rTMS”, which can produce longer lasting changes in brain activity.