An Examination of Interhemispheric Transfer and Asymmetry in Autism: Behavioral and Neuroimaging Evidence for Underconnectivity
AuthorJung, Corinne E.
AdvisorHutsler, Jeffrey J.
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Though diagnosis of idiopathic autism spectrum disorders (ASD) is primarily based on observations of abnormal social communication and behavior, a neurological basis of this prevalent disorder is widely agreed upon. The underconnectivity hypothesis is one theory that characterizes this physiological abnormality by proposing a failure of integration at both the neural and cognitive levels, a generalization also applied to other cognitive disorders. Here we used an index known as interhemispheric transfer (IHT) to assess connectivity in ASD. Impairments in IHT impede communication between the hemispheres and can potentially lead to a myriad of cognitive and behavioral abnormalities. The goal of the present study was to assess the impact of IHT deficits both in this population and in NT populations to achieve a better understanding of how these deficits can give rise to the symptoms of this disorder, making it distinct from, but still connected to, other disorders of underconnectivity. We also assessed the impact of IHT deficits on cognitive development by examining patterns of asymmetry for hemisphere dominant tasks using both behavioral tasks and neuroimaging techniques. Our results specifically implicate IHT deficits and consequential reduction of functional asymmetry in the behavioral profile of ASD. Collectively, this research supports underconnectivity in this population and provides insight to how deficits in IHT can cause the symptoms specifically associated with this diagnosis. These findings have potential contributions for the standard protocols by improving diagnostic and intervention methods to serve the ASD population more effectively.