In this paper we review the pathophysiology of autism.1）The amygdala theory of autismThe network of neural regions that comprise the social brain includes the amygdala. There isa reduction in volume of amygdala in children with autism. The concentration of N-acetylaspartateis also decreased in amygdala of autistic brain. The amygdala is therefore proposed to be one ofseveral neural regions that are abnormal in autism.2）Mirror neuron dysfunction in autismChildren with autism underwent fMRI while imitating and observing emotional expressions.They showed no mirror neuron activity in the inferior frontal gyrus（pars opercularis）. Notably,activity in this area was inversely related to symptom severity in the social domain, suggestingthat a dysfunctional mirror neuron system may underlie the social deficits observed in autism
