Recent functional imaging studies have revealed serious deficits in speech sound discrimination in both children and adults with autism. The latency increase of speech evoked neural responses is well correlated with the degree of cognitive and language impairments. Unfortunately, the poor resolution of human imaging techniques obscures the neural basis of the impairment. This project will evaluate speech sound coding in the valproic acid (VPA) animal model of autism and quantify the beneficial effects of two common autism therapies: auditory training and environmental enrichment. Speech sounds evoke specific spatiotemporal patterns of cell firing in the central auditory system of normal rats. The first aim of the project is to determine the consequence of VPA exposure on the collicular and cortical representations of speech sounds. The second aim is to determine the behavioral consequences of VPA exposure on speech sound discrimination. If the neural spatiotemporal representations of speech sounds are degraded, then it is possible that certain speech sounds may not be distinguishable in VPA treated rats. The third aim is to determine the effects of speech training and environmental enrichment on speech evoked activity in VPA exposed rats. The results of the proposed studies will add to the understanding of the neural mechanisms that are associated with speech sound coding. Insights derived from these studies may influence the development of new behavioral and sensory techniques to treat the communication impairments in autism that result in part from degraded speech sound discrimination.