Neuropathological Findings in ASD - Childhood Disorders: The Autism Spectrum Disorders

Neuropathological Findings in ASD

Some investigators have found evidence for differences in the hippocampus and amygdala. While noting no gross abnormali-ties in their study of the brains of six autistic individuals, they have noted increased cell packing and diminished neuronal size in the hippocampus and some nuclei in the amygdala. They also found decreased complexity and extent of dendritic arbors in hippocampal pyramidal cells. They speculated that such lesions might produce changes in behavior similar to those with Klüver Bucy Syndrome (hyperexploratory behavior, severe impairment of social interaction) and some cases of limbic injuries leading to memory loss (and a subsequent “rigidly specific habit memory system”). Others (Bachevalier, 1994) have suggested that such changes might result in difficulty in assigning affective signifi-cance to social stimuli.

A number of investigators have noted loss of cerebellar Purkinje cells as well as changes in neurons of the deep cerebellar nuclei. Such findings have led to the hypothesis that these lesions could affect selective attention, in particular leading to stimulus overselectivity and difficulties in shifting attention.