Effects of repetitive transcranial magnetic stimulation in depression: a magnetoencephalographic study.

Recently, repetitive transcranial magnetic stimulation has evolved as a potential therapeutic tool to interfere with brain changes associated with neurological and psychiatric diseases. Little is known about its mode of action, however. Here, we investigated effects of repetitive transcranial magnetic stimulation on spontaneous magnetoencephalographic activity in patients with major depression. Before treatment, depressed patients showed a significant increase in slow magnetoencephalographic activity (2-6 Hz) over the left prefrontal cortex, compared with healthy controls. This activity significantly decreased during 10 days of repetitive transcranial magnetic stimulation, paralleled by clinical improvement. We conclude that therapeutic repetitive transcranial magnetic stimulation effects can be mirrored by changes of spontaneous magnetoencephalographic activity.