Journal of the Medical Association of Thailand Vol 92, No 11:NOVEMBER 2009 0125-2208 92 11 2009 Nov Basic Principle of Transcranial Magnetic Stimulation 1560 EN Paradee Auvichayapat Narong Auvichayapat Special Article Review TMS stimulator, types of stimulation, mechanism of action, and its application. There are three types of TMS stimulation: 1) Single pulse; used in studying ofmotor threshold and phosphene threshold. 2) Paired pulse; used in the study of intracortical inhibitory andfacilitatory mechanisms. 3) Repetitive stimulation; changes corticospinal/corticocortical pathway. The mechanisms increases activity of synapse, changes the secretion of neurotransmitter, and causesneuronal plasticity or long-term potentiation. Repetitive stimulation is used in fundamental basic sciencefor brain mapping. It is a new therapeutic method for neuro-psychiatic disorders that does not respond tomedications. TMS study is rapidly increasing and accepted as a noninvasive technique. The most favorabletreating outcomes are depression and Parkinson disease. Other neuro-psychiatic therapeutic outcomes areongoing. Transcranial Magnetic Stimulation TMS Neurophysiologic technique neuro-psychiatic disorders