Transcranial magnetic stimulation (TMS) is a highly precise and noninvasive brain stimulation tool approved by the U.S. Food and Drug Administration for the treatment of major depression and other conditions. TMS can only directly stimulate the outermost layer of the brain, but a recent study by researchers at the National Institute of Mental Health (NIMH) suggests that mapping a person’s brain architecture may make it possible to guide TMS to deep brain targets.