自然な刺激に対する海馬回路内の表象的分化と統合

The hippocampus is essential for transforming dynamic experiences into structured knowledge, forming internal models of the world that guide planning, decision-making, and behavior. Recent research has demonstrated that complementary hippocampal mechanisms-specifically, the differentiation of distinct experiences and the integration of related information-fundamentally underlie cognitive map formation during spatial navigation. However, there is limited empirical evidence on how these processes support network-based, map-like representations during complex continuous stimuli. Here, using the Human Connectome Project 7T naturalistic dataset, we explored how the canonical hippocampal circuit (DG-CA3-CA1) supports differentiation and integration from movie stimuli. Our results found that the hippocampus encoded both semantic features and small-world network representations from movie stimuli. Moreover, we observed representational differentiation in geodesic network distances within the DG-CA3 pathway, while integration predominated in the CA3-CA1 pathway. Inter-subject functional correlation analysis revealed that stronger hippocampal-cortical connectivity-especially with the retrosplenial cortex, parahippocampal cortex, medial prefrontal cortex, and visual regions-was positively correlated with CA3-CA1 integration capacity. Notably, CA1-retrosplenial connectivity emerged as a key mediator linking hippocampal integration to individual cognitive performance. These insights reveal how the hippocampus dynamically differentiates and integrates movie information, highlighting the importance of hippocampal-retrosplenial interactions in linking hippocampal integration processes with cognitive abilities.