"Over the past several decades, brain stimulation has become an increasingly important treatment option for a number of psychiatric and neurological conditions.
Divided into two broad approaches, invasive and noninvasive, brain stimulation works by targeting specific sites to adjust brain activity. The most widely known invasive technique, deep brain stimulation (DBS), requires brain surgery to insert an electrode and is approved by the U.S. Food and Drug Administration (FDA) for the treatment of Parkinson’s disease and essential tremor. Noninvasive techniques, including transcranial magnetic stimulation (TMS), can be administered from outside the head and are currently approved for the treatment of depression. Brain stimulation can result in dramatic benefit to patients with these disorders, motivating researchers to test whether it can also help patients with other diseases."