Neha Uppal, Isabella Gianatiempo, Bridget Wicinski, James Schmeidler, Helmut Heinsen, Christoph Schmitz, Joseph D. Buxbaum, Patrick R. Hof

• Background: While most neuropathologic studies focus on regions involved in behavioral abnormalities in autism, it is also important to identify whether areas that appear functionally normal are devoid of pathologic alterations. In this study we analyzed the posteroinferior occipitotemporal gyrus, an extrastriate area not considered to be affected in autism. This area borders the fusiform gyrus, which is known to exhibit functional and cellular abnormalities in autism. Findings: No studies have implicated posteroinferior occipitotemporal gyrusBackground: While most neuropathologic studies focus on regions involved in behavioral abnormalities in autism, it is also important to identify whether areas that appear functionally normal are devoid of pathologic alterations. In this study we analyzed the posteroinferior occipitotemporal gyrus, an extrastriate area not considered to be affected in autism. This area borders the fusiform gyrus, which is known to exhibit functional and cellular abnormalities in autism. Findings: No studies have implicated posteroinferior occipitotemporal gyrus dysfunction in autism, leading us to hypothesize that neuropathology would not occur in this area. We indeed observed no significant differences in pyramidal neuron number or size in layers III, V, and VI in seven pairs of autism and controls. Conclusions: These findings are consistent with the hypothesis that neuropathology is unique to areas involved in stereotypies and social and emotional behaviors, and support the specificity of the localization of pathology in the fusiform gyrus.…