Fate-Restricted Neural Progenitors in the Mammalian Cerebral Cortex

Abstract

Generating the Cortex During development of the cerebral cortex, radial glial neural progenitor cells generate layer-specific subtypes of excitatory neurons in a defined temporal sequence, in which deep layers are formed before upper layers. The prevailing model for cortical neurogenesis over the last 20 years has been the common progenitor model, which proposes that the neurogenic potential of the radial glial cell is progressively restricted over time. In contrast to this model, Franco et al. (p. 746 ) now show that, in mice, two radial glial cell subtypes appear to be specified at the onset of cortical development: one for neurons of the evolutionarily older lower cortical layers and a second for the upper cortical layers that are present in placental mammals and are enlarged in primates, especially humans.