We used neuropsychological tasks to investigate integrity of brain circuits linking orbitofrontal cortex and amygdala (orbitofrontal-amygdala), and dorsolateral prefrontal cortex and hippocampus (dorsolateral prefrontal-hippocampus), in 138 individuals aged 7 -18 years, with and without autism. We predicted that performance on orbitofrontal-amygdala tasks would be poorer in the Autism group compared to the Non-Autism group regardless of intellectual level (verbal mental age -VMA) and that performance on dorsolateral prefrontal-hippocampus tasks would be associated primarily with intellectual level. Predicted differences between Autism and Non-Autism groups on orbitofrontalamygdala tasks were present but greater in individuals with higher VMA. On dorsolateral prefrontalhippocampus tasks, poorer performance by the Autism compared to the Non-Autism group was found at all VMA levels. Group differences suggest both brain circuits are impaired in autism, but performance on all tasks is also associated with intellectual level.Recent human studies using behavioral and neuroimaging techniques, as well as studies using animal models, have provided numerous clues to the underlying structural and functional brain changes associated with autistic spectrum disorders (hereafter, autism). Children and adults with autism have been shown to have developmental abnormalities and functional impairment of the frontal lobe, medial temporal structures, and cerebellum, as reflected in histopathology, structural and functional neuroimaging, electrophysiology, and neuropsychological studies (see for review, Bachevalier & Loveland, 2003). However, because autism is developmental in nature, it is unlikely to be based in focal abnormalities of any single neural structure or region, but instead is more likely to be distributed in neural networks. Consequently, developmental brain abnormalities in autism would be expected to affect brain circuits and the interaction of brain regions both during behavior and over the course of development. Two Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
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NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscript brain regions have repeatedly been implicated in autism: the prefrontal and medial temporal regions. These two regions are heavily interconnected and form two neural networks that appear to be critical for the monitoring of social cognition, executive functions, and episodic memory (see for review Bachevalier & Loveland, 2006).Based on the characteristics of their anatomical connections, the prefrontal-temporal network...