The division of neuronal progenitor cells during migration in the neonatal mammalian forebrain.

In the mammalian forebrain most neurons originate from proliferating cells in the ventricular zone lining the lateral ventricles. These neurons become postmitotic before they undergo migration to their final destinations. In this study we examined the proliferative and migratory properties of cells destined for the olfactory bulb that arise postnatally from progenitor cells situated at the anterior extent of the subventricular zone (SVZa). The SVZa-derived cells migrate along a stereotypical pathway to the olfactory bulb where they become interneurons. Using lineage tracers and the cell proliferation marker BrdU, we have demonstrated that SVZa-derived cells in the rat retain the capacity for division after migrating away from their initial site of generation. These cells also express a neuron-specific tubulin, recognized by the antibody TuJ1. These results suggest that, unlike other immature neurons, these SVZa-derived cells have made a commitment to become neurons before becoming postmitotic.