Population-Based Tract-To-Region Connectome of the Human Brain and Its Hierarchical Topology
Abstract Connectome maps region-to-region connectivities but does not inform which white matter pathways form the connections. Here we constructed the first population-based tract-to-region connectome to fill this information gap. The constructed connectome quantifies the population probability of a white matter tract innervating a cortical region. The results show that ~85% of the tract-to-region connectome entries are consistent across individuals, whereas the remaining (~15%) have substantial individual differences requiring individualized mapping. Further hierarchical clustering on cortical regions revealed their parcellations into dorsal, ventral, and limbic networks based on the tract-to-region connective patterns. The clustering results on white matter bundles revealed the connectome-based categorization of fiber bundle systems in the association pathways. This new tract-to-region connectome provides insights into the connective topology between cortical regions and white matter bundles. The derived hierarchical relation further offers a connectome-based categorization of gray matter and white matter structures.