No reduction of spindle neuron number in frontoinsular cortex in autism.

It has been suggested that spindle neurons, an evolutionarily unique type of neuron, might be involved in higher-order social, emotional, and cognitive functions. As such, it was hypothesized that these neurons may be particularly important to the pathophysiology of autism, a disease characterized in part by disruption of higher-order social and emotional processing. Therefore, we conducted the first stereological investigation of the number of spindle neurons in autism, using the optical fractionator technique. Our results did not provide evidence of a reduction in spindle neuron number in frontoinsular cortex in autism. However, this study provides the first quantitative stereological data on spindle neuron number in autism. Future postmortem studies with larger sample sizes will likely be critical in elucidating the spared and defective neural systems underlying the autistic phenotype.