Pathophysiology
In general, neuroanatomical studies support the notion that autism is linked to a combination of brain enlargement in some areas and brain reduction in other areas. These studies suggest that autism may be caused by abnormal neuronal growth and pruning during the early stages of prenatal and postnatal brain development, leaving some areas of the brain with too many neurons and other areas with too few neurons. Some research has reported an overall brain enlargement in autism while others suggest abnormalities in several areas of the brain, including the frontal lobe, the mirror neuron system, the limbic system, the temporal lobe, and the corpus callosum.
In neuroanatomical studies, it has been shown that for autistics there is reduced activation in the primary and secondary somato-sensory cortices during Theory of Mind and facial emotion response tasks when compared to control. This is consistent with reports of patterns of abnormal cortical thickness and grey matter volume in those regions in autistics.
Read more about this topic: Autism Spectrum