Cortical Patterning of Morphometric Similarity Gradient Reveals Diverged Hierarchical Organization in Sensory-Motor Cortices

The topographic organization of the cerebral cortex has been proposed to provide hierarchical axes, as gradients, which revealed systematic variations of brain structure and function. However, the hierarchical organization of macroscopic brain morphology and how it constrains cortical function along the organizing axis is still unclear. We mapped systematic axes (gradients) of cortical morphometric similarity connectome, which combined multiple morphometric features conceptualized as a “fingerprint” of an individual’s brain. We observed that the principal gradient was anchored by motor and sensory cortices at two extreme ends, which were stable across numbers of feature combinations and reproducible across independent samples. Importantly, in contrast to canonical functional gradient, the morphometric gradient diverged in motor and sensory hierarchies, and that was consistent to laminar histological thickness gradient. Furthermore, the morphometric and functional gradients dissociated in the higher-order association cortices, like the fronto-parietal and default mode networks. Finally, the spatial pattern of morphometric gradients was closely associated with fundamental properties of cortical organization, including cyto- and myeloarchitectural profiles, as well as evolutionary expansion. These findings help understand the hierarchical organization of morphological markers of cortical structure.