Social intelligence in the normal and autistic brain: an fMRI study

There is increasing support for the existence of 'social intelligence' [Hum phrey (1984) Consciousness Regained], independent of general intelligence. Brothers [(1990) J. Cog. Neurosci., 4, 107-118] proposed a network of neura l regions that comprise the 'social brain': the orbito-frontal cortex (OFC) , superior temporal gyrus (STG) and amygdala. We tested Brothers' theory by examining both normal subjects as well as patients with high-functioning a utism or Asperger syndrome (AS), who are well known to have deficits in soc ial intelligence, and perhaps deficits in amygdala function [Bauman & Kempe r (1988) J, Neuropath. Exp. Neurol,, 47, 369], We used a test of judging fr om the expressions of another person's eyes what that other person might be thinking or feeling. Using functional magnetic resonance imaging (fMRI) we confirmed Brothers' prediction that the STG and amygdala show increased ac tivation when using social intelligence. Some areas of the prefrontal corte x also showed activation. In contrast, patients with autism or AS activated the fronto-temporal regions but not the amygdala when making mentalistic i nferences from the eyes. These results provide support for the social brain theory of normal function, and the amygdala theory of autism.