Basic principle of transcranial magnetic stimulation.
BACKGROUND
Transcranial Magnetic Stimulation (TMS) is a new neurophysiological technique based on the principle of electromagnetic induction. When a pulse of current passes through a coil, it becomes a magnetic field and penetrates the scalp and skull, and reach the brain painlessly.


OBJECTIVE
Review TMS stimulator, types of stimulation, mechanism of action, and its application.


METHODS
There are three types of TMS stimulation: 1) Single pulse; used in studying of motor threshold and phosphene threshold. 2) Paired pulse; used in the study of intracortical inhibitory and facilitatory mechanisms. 3) Repetitive stimulation; changes corticospinal/corticocortical pathway.


RESULTS
The mechanisms increases activity of synapse, changes the secretion of neurotransmitter and causes neuronal plasticity or long-term potentiation. Repetitive stimulation is used in fundamental basic science for brain mapping. It is a new therapeutic method for neuro-psychiatic disorders that does not respond to medications.


CONCLUSIONS
TMS study is rapidly increasing and accepted as a noninvasive technique. The most favorable treating outcomes are depression and Parkinson disease. Other neuro-psychiatic therapeutic outcomes are ongoing.
Auvichayapat
Paradee
P
Department of Physiology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand. aparad@kku.ac.th
Auvichayapat
Narong
N
D003863:Depression / Q000628:therapy; D006801:Humans; D010300:Parkinson Disease / Q000628:therapy; D050781:Transcranial Magnetic Stimulation / Q000379:methods*