Intermediate neuronal progenitors (basal progenitors) produce pyramidal-projection neurons for all layers of cerebral cortex.

The developing cerebral cortex contains apical and basal types of neurogenic progenitor cells. Here, we investigated the cellular properties and neurogenic output of basal progenitors, also called intermediate neuronal progenitors (INPs). We found that basal mitoses expressing transcription factor Tbr2 (an INP marker) were present throughout corticogenesis, from embryonic day 10.

Role of intermediate progenitor cells in cerebral cortex development.

Intermediate progenitor cells (IPCs) are a type of neurogenic transient amplifying cells in the developing cerebral cortex. IPCs divide symmetrically at basal (abventricular) positions in the neuroepithelium to produce pairs of new neurons or, in amplifying divisions, pairs of new IPCs. In contrast, radial unit progenitors (neuroepithelial cells and radial glia) divide at the apical (ventricular) surface and produce only single neurons or single IPCs by asymmetric division, or self-amplify by symmetric division.