Bipartite functional fractionation within the neural system for social cognition supports the psychological continuity of self vs. other

Research of social neuroscience establishes that regions in the brains default network (DN) and semantic network (SN) are engaged by socio-cognitive tasks. Research of the human connectome shows that DN and SN regions are both situated at the high-order end of cortical gradient but differ in their positions on this gradient. In the present study, we integrated these two bodies of research, used the psychological continuity of self vs. other as a test-case, and used fMRI to investigate whether these networks would encode social concepts differently. We found a robust dissociation between the DN and SN - while both networks contained sufficient information for decoding broad-stroke distinction of social categories, the DN carried more generalisable information for cross-classifying across social distance and emotive valence than did the SN. We also found that the overarching distinction of self vs. other was a principal divider of the representational space while social distance was an auxiliary factor (subdivision, nested within the principal dimension), and this representational landscape was more manifest in the DN than in the SN. Taken together, our findings demonstrate how insights from connectome research can benefit social neuroscience, and have implications for clarifying the two networks differential contributions to social cognition.