Transcranial magnetic stimulation in neuropsychiatry

Abstract

Transcranial magnetic stimulation (TMS) and (rTMS) are noninvasive methods of brain stimulation with a broad range of basic neuroscience and potential future clinical applications. TMS is a new technology which holds promise as a treatment of psychiatric disorders. Most work to date has been on depression. Differences in physical properties of magnetic and electrical stimulation result in marked disparities in the amount and distribution of electrical current induced in the brain. TMS acutely modulates dopamine and serotonin content and turnover rates, and also modulates cortical beta-adrenergic receptors, reduces frontal cortex 5-HT2 receptors, increases 5-hydroxytryptamine 1A receptors in the frontal cortex and cingulum, and increases N-methyl-D-aspartate receptors in the ventromedial hypothalamus, basolateral amygdala, and parietal cortex. There was no limit to the number of treatment sessions which could be given and treatment was continued until remission occurred or response plateaued. The magnets are strong enough that pulsing them near a specific motor area of the cortex will result in movement of a specific muscle. Magnetic stimulation treatment, more focal than Ect, depolarizes neurons without anesthesia and neuromuscular blockade. TMS procedure can be conducted in an outpatient setting. Usually no adverse effects are noticed, except for occasional mild headache and discomfort at the site of stimulation.