Neural correlates of social and thematic semantics in autistic and non-autistic adults.

Conceptual knowledge-about objects, events, and social behaviour-is represented within the semantic system, but it is unclear if different conceptual categories engage the same portions of the system. This is perhaps most relevant for event-based, or thematic, knowledge and social knowledge which is acquired through social experiences. The present study investigated neural specialisation for social concepts by examining whether distinct semantic regions or hubs represent taxonomic versus thematic relations and social versus non-social relations. Specialisation was examined in two groups with different social experiences: autistic and non-autistic adults. There were minimal behavioural and no neural differences between groups, suggesting that differences in social experiences between autistic and non-autistic people may be better understood at the interactional level. In whole-brain analyses across both groups, taxonomic relations engaged the semantic control network to a greater extent than thematic relations did, and an overlapping portion of the rostroventral area of left angular gyrus was engaged by both thematic (relative to taxonomic) and social (relative to non-social) relations. Region of interest analyses revealed a more complex pattern within bilateral angular gyri. The results suggest that angular gyrus represents conceptual knowledge in a graded fashion, including specialisation for thematic and social relations.