Transcranial magnetic stimulation: studying the brain-behaviour relationship by induction of 'virtual lesions'

Transcranial magnetic stimulation (TMS) provides a non-invasive method of i nduction of a focal current in the brain and transient modulation of the fu nction of the targeted cortex. Despite limited understanding about focality and mechanisms of action, TMS provides a unique opportunity of studying br ain-behaviour relations in normal humans. TMS can enhance the results of ot her neuroimaging techniques by establishing the causal link between brain a ctivity and task performance, and by exploring functional brain connectivit y.