Repetitive transcranial magnetic stimulation: a tool for human cerebellar plasticity.

Non-invasive brain stimulation methods, such as repetitive transcranial magnetic stimulation (rTMS), are currently used to modulate the excitability of the cerebral cortex, providing important insights into mechanisms of cortical plasticity. Used to create long-lasting changes in the excitability of synapses, rTMS has been intensively investigated as a therapeutic tool in several neurological and psychiatric conditions and given some promising results. Recent studies have shown that rTMS of cerebellar structures is capable of inducing long-lasting changes in the excitability of cerebello-thalamo-cortical pathways. Thus, this novel approach may be important for investigating the functions of cerebellar plasticity. Indeed, cerebellar rTMS has been shown to modulate motor control, cognitive functions, emotion and mood. Moreover, recent studies seem to indicate that long-lasting modifications of cerebellar pathways could be usefully exploited in the treatment of several pathological conditions characterized by altered cortical excitability, such as Parkinson's disease, stroke, depression and schizophrenia. The high potential of cerebellar rTMS as a therapeutic tool in neurology could depend on the possibility of modulating several interconnected remote areas, through the activation of different systems, such as the cerebello-thalamo-cortical and limbic-thalamo-cortical networks.