Every individual makes a difference: A trinity derived from linking individual brain morphometry, connectivity and mentalising ability

• Published in: Human brain mapping Vol. 44; no. 8; pp. 3343 - 3358
• Main Authors: Li, Zhaoning, Dong, Qunxi, Hu, Bin, Wu, Haiyan
• Format: Journal Article
• Language: English
• Published: Hoboken, USA John Wiley & Sons, Inc 01.06.2023
• Subjects: Amygdala; Amygdala - diagnostic imaging; Brain; Brain - diagnostic imaging; Cognition; dyadic regression analysis; Hippocampus; Humans; Hypotheses; interactive mentalisation questionnaire; inter‐subject representational similarity analysis; Isomorphism; Magnetic Resonance Imaging; mentalising; Metacognition; Morphometry; Neural networks; Regression Analysis; resting‐state functional connectivity; Similarity; Social interactions; Social life & customs; Statistical analysis; Structure-function relationships; surface‐based multivariate morphometry statistics; mentalising; resting-state functional connectivity; interactive mentalisation questionnaire; dyadic regression analysis; surface-based multivariate morphometry statistics; inter-subject representational similarity analysis
• ISSN: 1065-9471; 1097-0193; 1097-0193
• DOI: 10.1002/hbm.26285

Mentalising ability, indexed as the ability to understand others' beliefs, feelings, intentions, thoughts and traits, is a pivotal and fundamental component of human social cognition. However, considering the multifaceted nature of mentalising ability, little research has focused on characterising individual differences in different mentalising components. And even less research has been devoted to investigating how the variance in the structural and functional patterns of the amygdala and hippocampus, two vital subcortical regions of the “social brain”, are related to inter‐individual variability in mentalising ability. Here, as a first step toward filling these gaps, we exploited inter‐subject representational similarity analysis (IS‐RSA) to assess relationships between amygdala and hippocampal morphometry (surface‐based multivariate morphometry statistics, MMS), connectivity (resting‐state functional connectivity, rs‐FC) and mentalising ability (interactive mentalisation questionnaire [IMQ] scores) across the participants (N=24). In IS‐RSA, we proposed a novel pipeline, that is, computing patching and pooling operations‐based surface distance (CPP‐SD), to obtain a decent representation for high‐dimensional MMS data. On this basis, we found significant correlations (i.e., second‐order isomorphisms) between these three distinct modalities, indicating that a trinity existed in idiosyncratic patterns of brain morphometry, connectivity and mentalising ability. Notably, a region‐related mentalising specificity emerged from these associations: self‐self and self‐other mentalisation are more related to the hippocampus, while other‐self mentalisation shows a closer link with the amygdala. Furthermore, by utilising the dyadic regression analysis, we observed significant interactions such that subject pairs with similar morphometry had even greater mentalising similarity if they were also similar in rs‐FC. Altogether, we demonstrated the feasibility and illustrated the promise of using IS‐RSA to study individual differences, deepening our understanding of how individual brains give rise to their mentalising abilities. A trinity existed in idiosyncratic patterns of brain morphometry, connectivity and mentalising ability, that is, three distinct modalities shared one essence.