Research on the cognitive deficits and neurology of individuals with autism suggests the presence of abnormalities in a number of areas. This may be because an early defect in the functioning of one or more areas of the brain alters the development of multiple other areas. The following sections describe evidence supporting dysfunctions in autism of four areas of the brain: The amygdala, the frontal lobe, the temporal lobe, and the cerebellum.
According to Temple Grandin symptoms that resemble frontal lobe damage are a big part of autism. In other words, a person with autism shows symptoms that are similar to someone with undeveloped frontal lobes, even though the autistic person does not have a smaller or damaged frontal lobe.
Grandin says: “…even though autistic people have a normal-sized neocortex including normal-sized frontal lobes, [autistic people’s] brains function as if [the] frontal lobes were either much smaller or not fully developed.”
Grandin theorizes that the appearance of frontal lobe problems in autistic people is caused by a lower than normal amount of communication between the frontal lobes and other parts of the brain.
In support of this hypothesis she states that while scientists have not found undeveloped frontal lobes in autistic people, they have found fewer connections between cortical regions and also between the cortex and the subcortex. The lack of connections (and therefore lack of communication) between parts of the autistic brain leads to less input from the rest of the brain into the frontal lobes. Without the proper input the frontal lobes can’t give proper output.