People with autism experience difficulties with movement. Some have difficulty skipping or pedaling a tricycle, and social and communicative gestures such as waving or blowing a kiss can also be difficult to execute. These impairments may be due to problems with motor learning, which would make it difficult to acquire complex patterns of movements. These motor deficits may stem from abnormalities within a number of brain areas that control motor learning and function. This project seeks to understand the neural basis of these motor deficits by finding relationships between brain anatomy and motor function. The focus on motor function is an advantage because, unlike many behavioral measures of autism, measures of motor function are highly quantifiable and reproducible. These measures will be compared to detailed brain images obtained with anatomic magnetic resonance imaging (aMRI). This proposal plans to continue detailed mapping of cortical and subcortical brain structures, including cerebral cortex, basal ganglia, thalamus, and cerebellum. Different measures of structure such as volume and thickness will be made from these high-resolution images, and compared to motor function to pinpoint brain areas affected by autism. What this means for people with autism: Investigations of motor skill learning and the associated brain areas can help pinpoint the dysfunctional neural circuits in autism. Comparisons of motor function and high-resolution images of brain structure will help reveal the neural basis of these difficulties, and will advance our understanding of the brain regions involved in social and communicative gestures.