Cerebral function revealed by transcranial magnetic stimulation

Although transcranial magnetic stimulation (TMS) has been introduced only r ecently, it is safe and provides a painless, inexpensive noninvasive method for the evaluation of brain function. Determining central motor conduction time (CMCT) permits assessment of the corticospinal pathways. Mapping the central representation of muscles provides a method for investigating the c ortical reorganization that follows training, amputation and injury to the central nervous system. Such studies of human plasticity may have important implications for neurorehabilitation. TMS also provides a method whereby c ortical excitability can be noninvasively evaluated, which is likely to hav e important implications in the study of epilepsy, movement disorders and r elated conditions. TMS is useful in tracking the flow of information from o ne brain region to another and in investigations of cognition and functiona l localization, thereby complementing information obtained using functional imaging techniques, which have superior spatial but inferior temporal reso lution. Finally, TMS is currently being investigated as a method for establ ishing cerebral dominance and as a therapeutic tool in the treatment of dep ression. Investigations for treatment of other neurologic and psychiatric c onditions are likely to be undertaken. (C) 1999 Elsevier Science B.V. All r ights reserved.