The purpose of this study is to investigate the underlying brain systems that mediate Tourette Syndrome. The new brain imaging technique of functional magnetic resonance imaging (fMRI) will be used to compare adults with Tourette Syndrome with a control group of adults who do not have any psychiatric or neurologic disorder. This approach will allow the investigators to test theories about which brain circuits are functioning abnormally in adults with Tourette Syndrome. The technique of fMRI allows researchers to take pictures that reflect changes in regional brain activity from moment to moment. During the brain imaging sessions, study subjects will be performing specially designed behavioral tasks through interaction with a computer. The behavioral tasks will be developed so as to invoke activation of the same brain circuits that are thought to be affected in Tourette Syndrome. In this way, the investigators will be able to graphically demonstrate whether the brain activation patterns involving these circuits differ between subjects with Tourette Syndrome and control subjects. If such differences are found, the investigators will be able to also locate the functional abnormalities very precisely. The hope is that this line of research will contribute new information about the neurobiology of Tourette Syndrome. Such information could ultimately influence the search for new treatments. Furthermore, with future refinements, such tests could prove useful clinically for predicting which patients will respond best to specific therapies. Scott L. Rauch, M.D. Massachusetts General Hospital (Harvard Medical School), Boston, MA Award $22,593 Tourette Association of America Inc. – Research Grant Award 1995