Abstract
Evidence suggests that individuals with autism exhibit hypoactivation in core face processing regions, including in the fusiform gyrus (FG), the occipital face area (OFA), and the posterior superior temporal sulcus (STS), and this hypoactivation is evident even in early adolescence (Scherf et al., 2010). In 20 high-functioning adolescents with autism (HFA) and 12 typically developing (TD) age, gender, and FSIQ-matched controls, we explored the possibility that there may be additional alterations in activation within extended regions of the face-processing network, including the VMPFC, amygdala, posterior cingulate (PC), and anterior temporal pole. We also evaluated the extent to which hypoactivation in face-related regions is related to the magnitude of autism-like symptoms, as measured with the Social Responsiveness Scale. Participants performed a 1-back task during the fMRI localizer, which included blocks of fearful faces, neutral faces, common objects, novel objects, vehicles, houses, and scrambled images. When analyzed in a group model, the TD adolescents exhibited strong face-related activation in both core (FFA, OFA, STS) and extended (anterior temporal pole, VMPFC, amygdala, PC) regions that was somewhat right lateralized. Interestingly, the HFA adolescents exhibited bilateral FFA activation; however, it was smaller in extent than in the TD adolescents, particularly in the right hemisphere. There was a dramatic reduction, and often a complete absence of activation, in the other core regions (OFA, STS) as well as in all of the extended regions. Furthermore, this hypoactivation was correlated with the severity of autism symptoms. Specifically, HFA individuals with more severe symptoms exhibited lower magnitude face-related, but not object-related, activation in the right FG and OFA. This correlation was absent in the TD adolescents. These findings indicate that the extent of atypicality in the functional organization of neural regions supporting face processing in autism is much broader than previously reported and is related to symptom severity.
Meeting abstract presented at VSS 2013