Exploring motor cortical plasticity using transcranial magnetic stimulation in humans.

It is generally accepted that functional properties of the motor cortex in adult humans can be altered through behavioral or pharmacological manipulations, as well as in some pathological conditions. The ability and capacity of adult human cortex to undergo any adaptive or reorganizational changes is referred to as plasticity. Much of the evidence concerning motor cortical plasticity have been derived from studies using the non-invasive technique of transcranial magnetic stimulation (TMS). TMS has proven to be a suitable tool to explore representational plasticity and to interact with neuronal activity in settings of induction protocols either alone or coupled with altered sensory inputs. Furthermore, plastic changes induced by motor learning protocols have attracted particular interest because of their relevance in functional recovery. Recent studies support the view that learning in human motor cortex occurs through long-term potentiation (LTP)-like mechanisms. Purposeful modulation of motor cortical plastic changes by manipulative TMS protocols may offer useful rehabilitative strategies in patients with chronic motor deficits.