From stem and progenitor cells to neurons in the developing neocortex: key differences among hominids.

Comparing the biology of humans to that of other primates, and notably other hominids, is a useful path to learn more about what makes us human. Some of the most interesting differences among hominids are closely related to brain development and function, for example behaviour and cognition. This makes it particularly interesting to compare the hominid neural cells of the neocortex, a part of the brain that plays central roles in those processes. However, well-preserved tissue from great apes is usually extremely difficult to obtain. A variety of new alternative tools, for example brain organoids, are now beginning to make it possible to search for such differences and analyse their potential biological and biomedical meaning. Here, we present an overview of recent findings from comparisons of the neural stem and progenitor cells (NSPCs) and neurons of hominids. In addition to differences in proliferation and differentiation of NSPCs, and maturation of neurons, we highlight that the regulation of the timing of these processes is emerging as a general foundational difference in the development of the neocortex of hominids.