Beyond white matter topology: cortical geometry shapes the spatial pattern of face-processing plasticity following auditory deprivation.

The human brain can adapt its function in response to experience, and such plasticity mediates the influence of individual experience on cognition and behavior. Traditional accounts propose that functional brain plasticity is primarily driven by the rerouting of white matter fiber networks, that is, topological connectivity. However, accumulating evidence that intrinsic geometric features constrain neural dynamics raises the possibility that brain plasticity may also be shaped by cortical geometry. Yet, direct empirical support for this hypothesis remains scarce. Here, we combined a multivariate analytical framework with multimodal neuroimaging to examine how white matter topology and cortical geometry jointly constrain the group-level spatial pattern of face-processing plasticity following congenital auditory deprivation. Our results showed that auditory deprivation-induced functional plasticity primarily exhibited a spatial pattern of outward expansion from the core regions of the pre-existing face-processing network. Both white matter topology and cortical geometry were associated with the spatial distribution of this group-level plasticity map, with cortical geometry explaining a modest but greater portion of its spatial variance than topological connectivity. Whole-brain eigenmode analysis further showed greater alignment of face-processing activation with geometric eigenmodes in deaf participants at intermediate spatial scales, with no comparable differences for connectome eigenmodes. Moreover, cross-group predictive analyses indicated that structure-function associations involving topological and geometric properties can partially generalize across sensory experience. Taken together, these findings suggest that cortical geometry, as one component of the structural scaffold, contributes to the spatial organization of group-level functional plasticity alongside white matter topology, consistent with complementary structural constraints on its spatial pattern.