Abnormal ventral temporal cortical activity during face discrimination among individuals with autism and Asperger syndrome

Background: Recognition of individual faces is an integral part of both int erpersonal interactions and successful functioning within a social group. T herefore, it is of considerable interest that individuals with autism and r elated conditions have selective deficits in face recognition (sparing nonf ace object recognition). Method: We used functional magnetic resonance imaging (fMRI) to study face and subordinate-level object perception in 14 high-functioning individuals with autism or Asperger syndrome (the autism group), in comparison with 2 g roups of matched normal controls (normal control group 1 [NC1] and normal c ontrol group 2 [NC2]) (n = 14 for each). Regions of interest (ROIs) were de fined in NC1 and then applied in comparisons between NC2 and the autism gro up. Regions of interest were also defined in NC2 and then applied to compar isons between NC1 and the autism group as a replication study. Results: In the first set of comparisons, we found significant task X group interactions for the size of activation in the right fusiform gyrus (FC) a nd right inferior temporal gyri (ITG). Post hoc analyses showed that during face (but not object) discrimination, the autism group had significantly g reater activation than controls in the right ITG and less activation of the right FG. The replication study showed again that the autism group used th e ITG significantly more for processing faces than the control groups, but for these analyses, the effect was now on the left side. Greater ITG activa tion was the pattern found in both control groups during object processing. Conclusions: Individuals with autism spectrum disorders demonstrate a patte rn of brain activity during face discrimination that is consistent with fea ture-based strategies that are more typical of nonface object perception.