Recent studies demonstrated the neuronogenic role of radial glial cells (RGCs) in the rodent. To reveal the fate of radial glial processes, we intensively monitored divisions of RGCs in DiI-labeled slices from the embryonic day 14 mouse cortex. During RGC division, each pia-connected fiber becomes thin but is neither lost nor divided; it is inherited asymmetrically by one daughter cell. In divisions that produce a neuron and a progenitor, the neuron inherits the pial fiber, also grows a thick ventricular process for several hours, and is therefore indistinguishable from the progenitor RGC. The ventricular process in the radial glial-like neuron (“radial neuron”) then collapses, leading to ascent of the neuron by using the “recycled” radial fiber.

Asymmetric Inheritance of Radial Glial Fibers by Cortical Neurons