Brain imaging studies in patients with ASD indicate that deficits in social cognition, language, communication and stereotypical behaviors may be related to functional alterations in specific brain regions, particularly the frontal and temporal cortical areas. Neuroanatomical and neuropathological investigations also point to early developmental abnormalities which affect cortical neuronal cytoarchitecture. Within the cerebral cortex, the cell bodies of neurons are organized radially into discrete cytoarchitectural units called ‘minicolumns'. Recent studies have revealed that minicolumns, and the neuronal cell bodies that make them up, are reorganized within the prefrontal, cingulate and inferior temporal cortices in autism. However, it is not known whether such structural reorganization also affects the distribution of dendrites (cellular processes) that originate from neurons in minicolumns, thereby critically altering the processing of neural information within these cortical areas. This project will address the fundamental question of whether dendritic architecture is altered within regions of the cerebral cortex known to be affected in autism. Sophisticated image analysis will be carried out on defined cortical areas in post-mortem materials obtained from ASD and matched control cases (supplied by Autism Speaks' Autism Tissue Program). Using a coordinated and systematic approach, this project will obtain detailed insight into the extent to which information processing, at the level of select dendritic networks, is altered within functionally-defined areas of the cortex in ASD. What this means for people with autism: These findings will determine whether the neurobiological basis for the core behavioral changes observed in ASD can be related to dendritic reorganization within the cerebral cortex. This helps guide future design of targeted biological treatments.