Cell-cycle control and cortical development

Primate corticogenesis is characterized by a number of unique features including the existence of a unique germinal zone, the outer subventricular zone, which is largely responsible for the generation of upper layer neurons.Multiple proliferative programmes exist in the germinal zone of the cortex that are responsible for the generation of cytoarchitecturally distinct cortical areas.Cell-cycle regulation and in particular the G1-phase control, has a major role in determining neuron number in the cerebral cortex.The developmental mechanisms that establish the precise number of neurons in individual areas and layers are dependent on the integration of intrinsic and extrinsic factors.Embryonic thalamocortical projections are likely to influence areal specification during early stages of corticogenesis by modulating proliferation.