A Stereologic Perspective on Autism Neuropathology

Autism spectrum disorders are symptomatically defined conditions affecting 1 in 88 children in the United States. Behavioral symptoms of autism patients combined with qualitative studies of brain sections indicate that pathology will be strongly represented in cerebral cortex. The role for the prefrontal cortex (PFC), usually categorized as "executive functions," is thought to regulate planning, decision making and, most importantly, social behavior. Cortical neurons are generated in excess early in gestation, and this overabundance may be even larger in children with autism. Impairment in apoptosis during early postnatal life, which typically removes subplate neurons, may also contribute to the excess amount of cortical neurons in autism. This chapter discusses several neuropathological studies. The differences in results between two studies highlight the importance of having both detailed analysis of individual areas and broad analysis of regions, as they both give distinct views on the effect of autism on brain pathology.