Neurons and glial cells of the forebrain arise ultimately from a pseudostratified ventricular epithelium (PVE), which lines the ventricular margins of the embryonic cerebral vesicles (1 ). Neurons that undergo their terminal mitosis in this epithelium migrate directly to the target structures. Other cells, arising concurrently with neurons, move outward into the cerebral wall, where they constitute a stem cell population that may give rise to both glial cells and neurons over the life of the organism. We describe methods to characterize the proliferative behavior of the PVE of the mouse forebrain. These methods are directly applicable to pseudostratified proliferative epithelial structures that give rise to the CNS and certain somatic structures.
