Human-specific genetic hallmarks in neocortical development: focus on neural progenitors

The evolutionary expansion of the neocortex in the ape lineage is the basis for the development of higher cognitive abilities. However, the human brain has uniquely increased in size and degree of folding, forming an essential foundation for advanced cognitive functions. This raises the question: what factors distinguish humans from our closest living primate relatives, such as chimpanzees and bonobos, which exhibit comparatively constrained cognitive capabilities? In this review, we focus on recent studies examining (modern) human-specific genetic traits that influence neural progenitor cells, whose behavior and activity are crucial for shaping cortical morphology. We emphasize the role of human-specific genetic modifications in signaling pathways that enhance the abundance of apical and basal progenitors, as well as the importance of basal progenitor metabolism in their proliferation in human. Additionally, we discuss how changes in neuron morphology contribute to the evolution of human cognition and provide our perspective on future directions in the field.