The purpose of this study is to investigate the influence of transcranial magnetic stimulation (TMS) on free will to select movement. There have been debates that most of human voluntary movements are reflexive rather than volitional in nature, although most people feel that their movements are freely chosen. This issue is illuminated by previous TMS studies showing external bias of freely chosen movements by TMS. Recently, we tried to confirm these observations using a more reliable method with subthreshold TMS, but failed. Thus, in this study, we are planning to use suprathreshold TMS to test whether this type of stimulation on different motor areas influences free selection of movements or not.
Normal adult volunteers who are 21 years or older will be eligible. Volunteers who have either any medico-surgical, neurological and psychiatric illnesses, who have been taking any medication with potential influence on nervous system function, who have a pacemaker, an implanted medical pump, a metal plate or a metal object in the skull or eye (for example, after brain surgery), or who have a history of seizure disorder, will be excluded.