The investigators have perfected a method that requires very short imaging periods (minutes) for measuring functional connectivity (defined as the degree of synchronization between distant brain regions) that they have shown to be exquisitely sensitive in detecting connectivity differences between typically-developing children, adolescents, and adults. Preliminary data indicates that this team can detect autism-related differences in functional connectivity in children with high-functioning autism who are between 8-14 years of age. Here, the investigators propose a two-year cross-sectional study to examine such measures of connectivity in young children (between 36 and 60 months of age) with autism spectrum disorder (ASD) compared to controls. A comparative analysis across cortical regions will allow the investigators to determine whether there is a regional bias that includes frontal cortex, which is most involved in processing social information. The investigators also have included the development of analytical and imaging technologies that will be broadly applicable across imaging sites. The study thus has the opportunity to expand greatly the capacity of neuroimaging research programs around the country to include ASD as a focus of their efforts.