Connectivity Profile and Function of Uniquely Human Cortical Areas

Abstract

Determining the brain specializations unique to humans requires directly comparable anatomical information from other primates, especially our closest relatives. Human ( Homo sapiens ; m/f), chimpanzee ( Pan troglodytes ; f), and rhesus macaque ( Macaca mulatta ; m/f) white matter atlases were used to create connectivity blueprints, i.e., descriptions of the cortical gray matter in terms of the connectivity with homologous white matter tracts. This allowed a quantitative comparison of cortical organization across the species. We identified human-unique connectivity profiles concentrated in temporal and parietal cortices and hominid-unique organization in the prefrontal cortex. Functional decoding revealed human-unique hotspots correlated with language processing and social cognition. Overall, our results counter models that assign primacy to the prefrontal cortex for human uniqueness.