Microglia are the immune cells in the central nervous system and control the brain homeostasis. When microglia find either infected or dead cells in brain, they are activated and ingest debris to maintain the normal brain condition. Although microglia modulate brain environment via macrophage-like aspects, they also play important roles in the developing brain. In the past few years, several researchers found a novel property of microglia that underlie the development of brain. These findings possibly shed light on the novel mechanisms by which the higher brain functions are mediated by microglia.
A few years ago, it was reported that microglia arise from embryonic yolk sac and infiltrate into brain during early developmental stage, followed by differentiation of matured microglia. It was also reported that microglia are differentiated from monocyte-derived macrophage, which invade the injured brain.