Human cortical dynamics reflect graded contributions of local geometry and network topography

The brain is a physically embedded and heavily interconnected system that expresses neural rhythms across multiple time scales. While these dynamics result from the complex interplay of local and inter-regional factors, the relative contribution of such mechanisms across the cortex remains unclear. Our study explored geometric, microstructural, and connectome-level constraints on cortex-wide neural activity. We leveraged intracranial electroencephalography recordings to derive an intrinsic coordinate system of human cortical dynamics. Using multimodal neuroimaging, we could then demonstrate that these patterns were largely explainable by geometric properties indexed by inter-regional distance. However, dynamics in transmodal association regions were additionally explainable by incorporation of inter-regional microstructural similarity and connectivity information. Our findings were consistent when cross-referencing electroencephalography and imaging data from large-scale atlases and when using data obtained in the same individuals, suggesting subject-specificity and population-level generalizability. Together, our results support gradual shifts in the balance of local and macroscale constraints on cortical dynamics and highlight a key role of transmodal networks in inter-regional cortical coordination.