Functional reorganization after lesions of the human brain: studies with transcranial magnetic stimulation.

Transcranial magnetic stimulation (TMS) can be used to map representations in brain, assess excitability and briefly deactivate brain regions. The study of brain plasticity in humans in a variety of circumstances has been supported by using TMS. TMS has been one of the tools used to demonstrate changes in motor map size, location and excitability in the setting of peripheral deafferentation, motor learning, and brain lesions such as stroke. In patients with hemispherectomy, recovery is mediated by enhanced activity in ipsilateral pathways, and this mechanism may also be operative after stroke, but the evidence is controversial. The best recovery after stroke is due to reorganization of the lesioned hemisphere. Rehabilitative strategies might well be able to enhance rehabilitative efforts.