Fig. 4
From: Factors that influence adult neurogenesis as potential therapy
Microglia and neurogenesis modulation. Microglia at the normal state is more likely to undergo neurogenesis rather than gliogenesis (a). Upon microglia activation by stress factors such as aging or injury, pro-inflammatory cytokines are released and enhance gliogenesis at the expense of neurogenesis (b). In the next stage, microglia reach an immunomodulatory state where anti-inflammatory cytokines are released and a preference for neurogenesis is returned (c). ‘A’ - Astrocyte, ‘O’ - Oligodendrocyte, ‘N’ - Neuron