Deficits in social information processing are well established in Autism Spectrum Disorders (ASD). A substantial literature now exists linking these deficits in ASD to activation abnormalities in specific brain areas such as superior temporal sulcus (STS) and ventromedial prefrontal cortex (vmPFC). However, this literature is based on paradigms that are often quite distinct from real-world social perception – e.g., still-photos of faces and people, cartoons, or anthromorphized shapes. Very few ASD studies have tested the performance of the “social brain” during the perception of naturalistic social stimuli.
The present study examined differences in brain activity between children with ASD and a typically developing control group (TDC) while viewing naturalistic movies of children playing during two different conditions: joint play or parallel play.
FMRI data were collected from ASD (n=11; 9 male) and TDC (n=17; 6 male) participants as they watched video clips of joint and parallel play. Additional data collection is ongoing in order to balance groups by gender, and to match on IQ. The only instruction given to participants was to attend to the movies. Following the paradigm, participants completed a recognition task to assess their attention to the stimuli. FMRI data analyses included traditional GLM-based procedures as well as techniques for measuring spatio-temporal patterns of coordinated activity (independent components analysis).
Mixed-effects analysis showed decreased activation (p<.05, cluster corrected) of social brain areas in ASD (including STS and vmPFC) during the perception of joint versus parallel play. Connectivity analyses also revealed important group differences in the interactions between brain structures. Both groups were more than 95% accurate on the post-scan recognition task, with no group differences.
The present data are among the first to establish differences in social brain function among individuals with ASD during the perception of naturalistic social interactions. In addition to more closely replicating real-word interactions, dynamic social stimuli appear to be well suited to eliciting sustained, system-wide differences in brain connectivity that may be absent from studies relying on static or anthromorphized stimuli. These results suggest that individuals with ASD might not appreciate differences in the manipulation of social interactions (joint vs. parallel play) used in this study.
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