Parkinson’s Disease (PD) and Tourette’s Syndrome (TS) have both been linked to disorders of the dopamine system. In collaboration with Tammy Hershey and Kevin Black, we are conducting combined cognitive and pharmacological neuroimaging of PD and TS patients to examine brain activation abnormalities related to dopamine dysfunction. Patients are scanned on and off L-DOPA while performing difficult cognitive control tasks (e.g., N-back, go-nogo). Results suggests that L-DOPA normalizes brain activation abnormalities in patients and that these changes are related to behavioral performance (Hershey et al., submitted).