Resident Neural Stem Cells

For most of the 20th century, the dogma was that new neurons could not be generated in the adult mammalian brain. Nowadays, neurogenesis in the mammalian is widely accepted, especially in two brain regions: the ventricular-subventricular zone (V-SVZ) around the lateral ventricles and the subgranular zone (SGZ) in the hippocampus. The cytoarchitecture of these neurogenic niches has been widely studied, and different cell types and molecules have been identified, but the permanence of neural stem cells versus progenitor cells in these niches remains elusive. Neurogenesis may be modulated by physiological and pathological processes. Understanding the signaling pathways that modulate neurogenesis is a potential therapeutic strategy to avoid its decline associated with aging and/or pathology, as well as to replace lost cells after injury or degenerative diseases. Lastly, neural stem cells isolated from neurogenic regions or generated from pluripotent stem cells are also promising future therapeutic strategies.