Laura Bradley¹, Zeynep Saygin¹; ¹The Ohio State Univeristy

The visual word form area (VWFA) sits at a unique intersection of high-level visual and language systems, yet the biological factors that anchor it to these systems remain poorly understood. A central question is whether the VWFA is more similar in its underlying organization to is visual neighborhood or by its connectivity tot language network. Functional and structural brain asymmetries support uniquely human abilities like language, and connectivity patterns in children can predict later VWFA location, suggesting that both local structure and long-range connections may constrain its emergence. Here, we combine neurotransmitter density profiles and functional connectivity to characterize the architecture of the VWFA. To address this, we examined category-selectivity regions in the ventral temporal cortex (VTC), including VWFA, face-selectivity regions (FFA, OFA), and object-selective regions (LO, PFS), alongside frontal and temporal language regions. Neurochemical architecture was quantified from mean PET-derived receptor density maps (1,238 adults, 20 neurotransmitters/transporters). We applied hierarchical clustering and representational similarity analysis to characterize relationships among neurotransmitter profiles across ROIs. Hierarchical clustering and RSA revealed that the frontal language regions are most distinct from temporal language and visual regions; face rois cluster with each other, object rois with each other. The VWFA is neurochemically most similar to temporal language regions. The distinct neurochemical profile of the VWFA from other visual regions and its similarity to temporal language regions suggest that neurochemical affinity may be the physical mechanism by which privileged connectivity between VWFA and temporal language cortex is instantiated in development.