 In embryonic life, the SVZ refers to a secondary proliferative zone containing neural progenitor cells, which divide to produce neurons in the process of neurogenesis.The primary neural stem cells of the brain and spinal cord, termed radial glial cells, instead reside in the ventricular zone (VZ) (so-called because the VZ lines the inside of the developing ventricles).In the developing cerebral cortex, which resides in the dorsal telencephalon, the SVZ and VZ are transient tissues that do not exist in the adult.