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Synchronized perception, asynchronous processing: Differing neural synchrony to social attribution animation in autistic and non-autistic adolescents
Poster Session C, Saturday, September 13, 11:00 am - 12:30 pm, Field House
Brea Chouinard1, Maryam Rahimi1, Clare Kelly2, Louise Gallagher3, Alona Fyshe1; 1University of Alberta, 2Trinity College Dublin, 3University of Toronto
There is a near-universal tendency for people to attribute humanlike characteristics to simple geometric shapes animated to enact a social plot. These types of social attribution animations have been used to investigate whether autistic and non-autistic people differ in the extent to which they attribute humanlike intentions, suggesting that autistic people identify fewer social elements and are less likely to afford social reasoning to the shapes. Here, we collected fMRI data from 53 adolescents (28 autistic) while they watched a social attribution animation. We investigated group differences in brain synchrony using inter-subject correlation (ISC) to capture shared neural responses over time. Specifically, we addressed: (1) group similarities/differences in neural synchrony, (2) which brain regions exhibited differences, (3) how synchronization fluctuated across movie duration, and (4) stimulus features associated with neural engagement. METHODS: We computed pairwise ISC within and between groups of autistic and non-autistic adolescents by correlating each participant’s voxelwise time course with every other participant’s (Pearson correlation). First, we computed whole-brain ISC, comparing within- and between-group values. Second, we performed a time-resolved ISC analysis using sliding windows to generate ISC time series, at each voxel, across the movie. Third, we adapted a component-based ISC analysis, where for each participant we decomposed voxel time courses into global (non-selective) and region-specific (selective) components. We used a ventral occipitotemporal seed (Brodmann areas 19/20/37) to extract and regress out the non-selective signal, and computed selective components corresponding to language, theory-of-mind, and motor networks. RESULTS: The non-autistic group (r=0.022) exhibited higher whole-brain ISC (p = 0.001) than the autistic group (r=0.0166). Both groups demonstrated strong synchronization in occipital cortex, while non-autistic participants additionally showed elevated synchronization in anterior medial temporal lobe. Time-resolved analysis revealed that when there were differences, non-autistic participants generally exhibited higher ISC, in areas such as Brodmann 8, 17, 21, 25, and 40, suggesting group differences in visual, cognitive control, semantic, emotional, and multisensory synchronization. For the stimulus features analysis, in both groups the theory-of-mind selective component exhibited the greatest frequency of synchronization compared to language and motor selective components, although to different movie events: in non-autistic participants, theory of mind peaks occurred during both broad social contexts and discrete social events, while autistic participant peaks occurred during interactions between two key characters. CONCLUSION: Autistic and non-autistic people both show robust synchronization in early visual regions during naturalistic movie viewing, but they do so more strongly within than across groups, and they diverge in higher-order network engagement over time. Non-autistic synchronization was broader and more consistent suggesting that recruitment of cognitive control, emotional regulation, and social reasoning networks was consistent across non-autistic people. Although selective component analysis showed that both groups exhibited theory of mind synchronization during socially meaningful moments, there were group differences in the frequency and distribution of synchronization. These results highlight shared perceptual engagement but different modes of higher-order social narrative processing in autistic and non-autistic adolescents.
Topic Areas: Disorders: Developmental, Computational Approaches