People with autism are characterized by problems with social cognition. However, the cause of these problems is still unclear. Dr. Bachevalier has developed a program of research to study the neural basis of social cognition impairments in autism. Her team works with a model of autism based in a group of rhesus monkeys with specific brain lesions in either the orbital frontal cortex or the amygdala. She and her colleagues have found that early dysfunction in the orbital frontal cortex and amygdala regions of the monkey brain results in social deficits similar to those seen in people with autism. This study will use the same monkey model to investigate the theory that people with autism have difficulty integrating auditory and visual information and that this deficit is linked to their ability to interpret complex social signals. The researchers will also use positron emission tomography (PET) to examine which parts of the brain are active during a facial processing task. They will then compare their results to findings using a similar task in children with autism. These comparisons help researchers identify with greater precision the role of particular brain regions and circuits in basic social difficulties seen in people with autism. What this means for people with autism: This study will use a powerful primate model of autism to test the idea that the difficulties people with autism have interpreting social signals may stem from an inability to integrate auditory and visual information. Data from this work will help pinpoint the neural structures involved in this kind of social cognition. And results from this work could be used to explore behavioral interventions aimed at helping people better interpret social signals.