Studying higher cerebral functions by transcranial magnetic stimulation.

TMS can be used to study higher cerebral functions by the virtual lesion paradigm. The major advantages of this method are that it could be used to produce a lesion anywhere the researcher wants without confusing cortical reorganization, and that it helps to establish a chain of cause and effect between the activity of the brain and behavior. With elucidation of the mechanism underlying the cortical function blocking, this technique will open up new possibilities for studying higher cerebral functions. In contrast to the online method in which TMS is delivered while subjects perform a certain task, the off-line method uses repetitive TMS to achieve lasting effects even after stimulation has ceased. The application of the offline method will extend from improving cognitive functions by TMS to the treatment of neurological and psychiatric patients.