Studies of human motor physiology with transcranial magnetic stimulation.
Transcranial magnetic stimulation (TMS) is a safe, noninvasive, and painless way to stimulate the human motor cortex in behaving human subjects. When it is applied as a single-pulse, measurements such as central conduction time, motor threshold, silent-period duration, recruitment curve, and mapping of muscle representation can be determined. Paired-pulse TMS is a useful way to examine cortical excitability. Single and paired-pulse TMS have been applied to study plasticity following amputation and cortical excitability in patients with dystonia. Another form of TMS is repetitive TMS (rTMS), with stimuli delivered repeatedly to a single scalp site. High-frequency rTMS can be used to transiently inactivate different cortical areas to study their functions. rTMS can also modulate cortical excitability. At stimulus frequencies higher than 5 Hz, rTMS increases cortical excitability, and stimulation around 1 Hz reduces cortical excitability. Modulation of cortical excitability by rTMS has therapeutic potential in psychiatric and neurological disorders.
Chen
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Division of Neurology and Playfair Neuroscience Unit, Toronto Western Research Institute, University of Toronto, Toronto, Ontario, Canada. robert.chen@uhn.on.ca
D004558:Electric Stimulation; D006801:Humans; D009044:Motor Cortex / Q000166:cytology* / Q000502:physiology*; D009046:Motor Neurons / Q000502:physiology*; D009068:Movement / Q000502:physiology*; D050781:Transcranial Magnetic Stimulation