Autism is a pervasive neurodevelopmental disorder in which multiple parts of the brain are affected. The most consistent neuropathological finding in autism is a reduced number of Purkinje cells, large neurons located in the cerebellum. The cerebellum is a part of the brain responsible for motor coordination, but how the cerebellar abnormalities found in autism affect behavior is not well understood. Recent preliminary data has suggested that decreased activity in particular regions of the cerebellum of autistic patients is associated with difficulties in controlling manual force and in visual pursuit systems (i.e., visual tracking of moving objects). In this study, Dr. Mosconi will examine the role of the cerebellum in controlling and modulating sensorimotor performance for eye and hand movements using functional magnetic resonance imaging (fMRI). FMRI is a technique used to visualize the activity of neural circuits. In this study, the focus will be on patterns of neural activity in the cerebellum during the performance of visual and sensorimotor tasks. The brains of adults with autism and age-matched controls will be imaged by fMRI while they perform a series of visual pursuit and grip force control tasks. The fMRI data should show whether differences in neural activity in the cerebellum of autistic patients correlate with specific difficulties in sensorimotor performance. This study may help us to understand the significance of the cerebellar abnormalities seen in autistic brains, as well as shed light on the role of the cerebellum in sensorimotor performance.