Social processing in autism spectrum disorder: an fMRI investigation

BACKGROUND Females with autism spectrum disorder (ASD) may present differently to affected males. This may be due to masking or camouflaging of some of the clinical symptoms. Consequently, it may appear that, to some degree, females experience less social impairment than affected males. Further, females with ASD may experience more, or different, neurobiological impairment compared to affected males when controlling for expected sexual dimorphisms. METHODS The sample comprised 58 participants; 28 (14 male, 14 female) had a confirmed diagnosis of high functioning autism or Asperger's syndrome (based on DSM-IV criteria), and 28 (14 male, 14 female) were NT controls. Participants underwent functional magnetic resonance imaging (fMRI) while observing and judging 12 videos depicting interactions between two triangles. Participants were required to evaluate the type of interaction observed in each of the videos (no interaction, psychological interaction, physical interaction). RESULTS Whole brain analysis indicated increased BOLD responses (p=.0001) in the left middle temporal gyrus, and inferior frontal lobe in the NT group compared to the ASD group while observing psychological interactions. With respect to gender, females with ASD showed increased BOLD responses in the right medial temporal region while observing psychological interactions, a difference that was not evident in the NT group. DISCUSSION NT individuals displayed increased activity in regions commonly associated with social processing compared to individuals with ASD. This is consistent with the social impairment observed in ASD. Moreover, these results suggest that females with ASD may process social stimuli differently to affected males, and NT females. Thus, the importance of furthering our understanding of sex differences in neurobiological mechanisms underpinning symptomatology of ASD is pertinent to improve diagnostic and intervention paradigms in the future