Basal process and cell divisions of neural progenitors in the developing brain.

The basal process is an extension of certain types of neural progenitors during brain development; that is, the neuroepithelial and radial glial cells, which show radial orientation, emanating from their cell body. Originally, the basal process was considered to serve as a scaffold for the migration of newborn neurons, but recent observations obtained by advanced genetic manipulations and microscopic methods show that the basal process has additional roles. In this review, we first summarize the role of the radial glial basal process for neuronal migration and signaling and for the proper organization of the developing brain. We then focus on the emerging roles of the basal process during the division of neural progenitor cells, specifically the various modes of division of neuroepithelial and radial glial cells.