Evolutionary elaboration of tissues starts with changes in the genome and location of the stem cells.For example, GABAergic interneurons of the mammalian neocortex are generated in the ventral telencephalon and migrate tangentially to the neocortex, in contrast to the projection neurons originating in the ventricular/subventricular zone (VZ/SVZ) of the dorsal telencephalon. In human and nonhuman primates, evidence suggests that an additional subset of neocortical GABAergic interneurons is generated in the cortical VZ and a proliferative niche, the outer SVZ. The origin, magnitude, and significance of this species-specific difference are notknown. We use a battery of assays applicable tothe human, monkey, and mouse organotypic cultures and supravital tissue to identify neuronal progenitors in the cortical VZ/SVZ niche that produce asubset ofGABAergic interneurons. Our findings suggest that these progenitors constitute an evolutionary novelty contributing to the elaboration of higher cognitive functions in primates.
Radonjić, N. V., Ayoub, A. E., Memi, F., Yu, X., Maroof, A., Jakovcevski, I., … Zecevic, N. (2014). Diversity of Cortical Interneurons in Primates: The Role of the Dorsal Proliferative Niche. Cell Reports, 9(6), 2139–2151. https://doi.org/10.1016/j.celrep.2014.11.026