 Dr. Kevin J. Black at Washington University is conducting a study to learn whether we can use MRI scans to test dopamine function in the brain and to determine whether the brain performs memory tasks differently in Tourette Syndrome TS. TS is a movement disorder characterized by vocal tics sounds and motor tics movements. We will measure how and where brain activity changes using magnetic resonance imaging MRI scans during memory tasks and after taking levodopa. Levodopa is a drug commonly used for the treatment of Parkinsons disease PD, a very different movement disorder. 