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Short-Range Structural Connectivity Supports Local Structure–Function Coupling in Functional Network Patches Mapped with Precision Functional Mapping

Poster Session C - Sunday, March 8, 2026, 5:00 – 7:00 pm PDT, Fairview/Kitsilano Ballroom

Parsa Nilchian^1,2 (), Megan Chang¹, Keith Jamison¹, Charles Lynch¹, Immanuel Elbau¹, Conor Liston^1,2; ¹Weill Cornell Medicine, ²Tri-Institutional MD-PhD Program

Understanding how structural and functional brain properties relate remains a central neuroscientific challenge. The leading model proposes a unimodal-to-heteromodal gradient, with high structure–function (SF) correspondence in sensory and low coupling in association networks. However, many brain networks consist of spatially distributed communities, and how SF coupling manifests at the community level remains unclear. We investigated local SF correspondence and hypothesized that spatially distinct network communities are connected by short-range U-fibers. We used multimodal neuroimaging data from 32 participants extensively scanned with multiband-multiecho fMRI and diffusion-weighted imaging (DWI). We combined precision functional mapping (PFM) to delineate individualized network organization with tractography to assess structural connectivity. SF relationships were examined across 20 networks. While global SF coupling did not exceed chance levels, local communities exhibited increased structural connectivity, measured by streamline counts and tested against rotation-based null distributions—suggesting that local anatomy supports functional coherence. We validated this finding by controlling for community size, shape, and orientation using a spin test, and by accounting for streamline length. To assess subject specificity, we projected each subject’s functional communities onto all other participants and found that in 31 of 32 cases, within-community connectivity was maximal in the subject from whom the community was derived. All findings replicated across probabilistic and deterministic tractography. Our results reveal that mesoscale anatomy shapes functional organization and support the biological validity of individualized network topographies mapped with PFM. These findings highlight the role of U-fibers in defining local network patches and advance our understanding of SF coupling in the brain.

Topic Area: METHODS: Neuroimaging