The model we propose to examine (prenatal exposure to sodium valproate) has been shown by others to result in changes in social and other behaviors that are similar to those seen in people with autism. We plan to focus on the biology, that is, to determine what changes in the brain underlie the behavioral deficits. Data generated during this study will add to the understanding of how changes in the brain contribute to social behavior. Determining exactly which brain regions underlie the social behavior deficits will allow clinicians to focus on imaging those specific parts of the brain to diagnose autism, and early and accurate diagnosis improves prognosis. Understanding the regions of the brain important for social behavior, and how changes in the gene expression, structure, and function of those regions affect social behavior will provide novel targets for therapeutic interventions such as oxytocin. Finally, understanding which particular times of pregnancy the developing brain is especially vulnerable will allow physicians to better manage care of their patients, as well as allowing them to inform their patients regarding the risks associated with taking drugs at those times. What this means for people with autism: Using VPA as a model, this study will provide information to scientists and clinicians to better understand the critical time periods by which environmental exposures may produce the most deleterious effects, and offers a potential pharmacological treatment which in the future could be used in the clinic for individuals with autism spectrum disorders.