Figure 1.

Neural stem cell (NSC) response to brain damage.

The NSC in the adult brain are localized in their niche at the brain subventricular zone (SVZ). In response to a brain damage insult, the NSCs migrate ① towards the damage site, where they can proliferate and generate differentiated cell types (neurons, astrocytes and glia) ②, on what seems to be a generalized response mechanism to damage. Similarly, during the growth of a brain tumor, the NSC migrate towards the tumor site ③, and can be visualized surrounding the tumor, although in this case there is no evidence for repair mechanisms. The NSC are not the only cells migrating in response to brain damage, since there is also evidence for the migration of neuroblasts towards the damage sites, although not depicted in the cartoon for clarity.