Cortical excitability and neurology: insights into the pathophysiology.

Transcranial magnetic stimulation (TMS) is a technique developed to non-invasively investigate the integrity of human motor corticospinal tracts. Over the last three decades, the use of stimulation paradigms including single-pulse TMS, paired-pulse TMS, repetitive TMS, and integration with EEG and functional imaging have been developed to facilitate measurement of cortical excitability.Through the use of these protocols, TMS has evolved in-to an excellent tool for measuring cortical excitability.TMS has high sensitivity in detecting subtle changes in cortical excitability, and therefore it is also a good measure of disturbances associated with brain disorders. In this review, we appraise the current literature on cortical excitability studies using TMS in neurological disorders.We begin with a brief overview of current TMS measures and then show how these have added to our understand-ing of the underlying mechanisms of brain disorders.