The amygdala theory of autism

By Baron-Cohen, S., Ring, H.A, Bullmore, E.T., Wheelwright, S., Ashwin, C., and Williams, S.C.R., (2000), Neuroscience and Biobehavioural Reviews, Vol. 24, pp. 355-364.

Brothers proposed a network of neural regions that comprise the “social brain”, which includes the amygdala. Since the childhood psychiatric condition of autism involves deficits in “social intelligence”, it is plausible that autism may be caused by an amygdala abnormality, In this paper we review the evidence for the social function of the amygdala. We then review evidence for an amygdala deficit in people with autism, who are will known to have deficits in social behaviour. This includes a detailed summary of our recent functional magnetic resonance imaging (fMRI) study involving judging from the expressions of another person’s eyes what the other person might be thinking or feeling. In this study, patients with autism or AS did not activated the amygdala when making mentalistic inferences form the eyes, whilst people without autism did show amaygdala activity. The amygdala is therefore proposed to be one of several neural regions that are abnormal in autism.
Brothers suggested from both animal lesion studies, single cell recording studies, and neurological studies that social intelligence was a function of three regions: the amygdala, the orbito-frontal cortex, and the superior temporal sulcus and gyrus. Together, she called these the “social brain”.

The fMRI study provides strong evidence of the role of the amygdala in normal social intelligence, and abnormality of the amygdala in autism.