The ultimate goal of this research program is to identify brain biomarkers of autism spectrum disorders (ASDs) and biologically-based ASD subtypes using multimodal magnetic resonance imaging (MRI). Participants (children and adults with ASD and healthy controls) undergo high-resolution anatomical MRI, functional MRI (fMRI), diffusion tensor imaging (DTI), and magnetic resonance spectroscopy (MRS). These diverse forms of data will be analyzed within a single imaging space using advanced image acquisition, image processing, and statistical modeling. These methods will facilitate a deeper understanding of the relationships between local volumes, functional activity, metabolite concentrations, and connectivity. Neurobiological ASD subtypes may emerge based on differential patterns of disturbances in distinct neural systems, and the identification of brain-based biomarkers in individuals with ASD will illuminate the neural bases of this heterogeneous disorder.