Robert T. Schultz, David Grelotti, Ami Klin, Fred Volkmar, and Donald J. Cohen
Recent neuroimaging studies of autism and normal controls provide important clues as to the functional circuitry of the "social brain". This presentation will review these data, highlighting several fMRI studies from our laboratory. Individuals with autism and related conditions frequently show subtle deficits in face recognition and perception. The ability to recognize and remember people by their face is critical for interpersonal relationships. It may also provide a perceptual sign post that is used by the brain to organize a social understanding of people and interpersonal relationships. We now have evidence from two fMRI studies that persons with autism fail to engage the fusiform gyrus face area (FFA) during face discrimination tasks. Moreover, FFA activation level predicts degree of social impairment as measured with the ADOS and it distinguished the subject group with autism from those with Asperger syndrome and PDD NOS. These results will be present along with pilot fMRI data on social perception and discrimination of facial expressions. Together, these results show that there is a distributed network of brain regions involved in interpreting dynamic social interactions that includes the amygdala, medial prefrontal cortices and posterior aspects of the superior temporal gyrus. Significantly, the results also show that the fusiform gyrus is part of the social neural network. This is of theoretical importance because the activation task used in this study does not involve facial percepts, but rather involves interacting geometric figures designed to represent human relationships. Engagement of the fusiform by abstract representations of people suggests that the fusiform participates more generally in understanding interpersonal relationships, and that it figures prominently in the neural mechanism underlying autism spectrum conditions.
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