Anatomical Differences in the Mirror Neuron System and Social Cognition Network in Autism Hadjikhani N (1,2), Joseph R (3), Snyder J (1), Tager-Flusberg H(3) Abstract: Cereb Cortex. 2005 Nov 23; [Epub ahead of print] Findings Autism spectrum disorders (ASD) are neurodevelopmental and are associated with social and emotional deficits; the neural basis for these difficulties is unknown. One characteristic of ASD is a lack of empathy and emotional engagement with others. There is some evidence that the neural basis of imitative and empathic behavior may be the mirror neuron system (MNS). The MNS is composed of a network of areas including the pars opercularis of the inferior frontal gyrus (IFG), the inferior parietal lobule (IFL), and the superior temporal sulcus (STS), which are activated during the observation and imitation of an action. In this study, 28 adult male participants (14 with ASD, 14 controls) had magnetic resonance imaging (MRI) brain scans so that thickness of the cerebral cortex could be measured. The areas that comprise the MNS were significantly thinner in subjects with autism compared with controls. The group with autism also had cortical thinning in other areas involved in social cognition. There was no difference between groups in other areas of the cortex. Cortical thinning of the MNS was correlated with severity of symptoms as measured by the Autism Diagnostic Interview-Revised (ADI-R).
Conclusions The social and emotional deficits seen in autism are associated with abnormal thinning of the MNS, but further research is needed to determine if the differences are a cause of the behavioral deficits or a consequence of a lack of input to specific brain areas resulting from abnormal cortical functioning or connectivity.
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