Narrative coherence shapes functional connectivity in default mode and frontoparietal networks.

Narratives are central to human cognition, yet the brain mechanisms supporting coherent story construction remain incompletely understood. In this study, we used a well-controlled naturalistic paradigm to isolate the neural basis of narrative coherence. Participants watched a foreign-language film with either intact or scrambled English subtitles, disrupting narrative understanding while preserving auditory and visual input. Whole-brain functional connectivity multivariate pattern analysis (fc-MVPA) revealed significant differences between conditions in the ventromedial prefrontal cortex (vmPFC), posterior cingulate cortex (PCC), lateral prefrontal cortex, and right angular gyrus-regions spanning the default mode and frontoparietal control networks. Seed-based correlation analyses showed stronger vmPFC and PCC coupling with lateral temporal and frontoparietal regions during coherent narratives, supporting semantic and contextual integration. In contrast, incoherent narratives increased connectivity between the default mode and attention networks, consistent with elevated cognitive demands. Finally, we observed a functional dissociation within the DMN: vmPFC-PCC coupling was enhanced during incoherent viewing, while PCC-precuneus coupling was stronger during coherent narratives. These results highlight dynamic reconfiguration across large-scale brain networks in support of real-world narrative comprehension.