 The capacity to coordinate thoughts and actions to execute goal-directed behaviors cognitive control and the capacity to anticipate, respond to, and learn from reward reward processing are key processes for human behavior. Dysfunction in these processes has been hypothesized to contribute to repetitive thoughts and behaviors in many disorders, including obsessive-compulsive disorder OCD, Tourette Syndrome TS, and eating disorders. The investigators will use multimodal imaging to investigate neural circuits that support cognitive control and reward processing, using pediatric OCD as a model system. The short-term goal is to clarify how circuit-based abnormalities contribute to repetitive thoughtsbehaviors; these data will inform future trans-diagnostic studies. The long-term goal is to identify control and reward circuit-abnormalities as targets for new trans-diagnostic treatments. 