Highlights • Hypothalamic microglia survey the embryonic environment by touching radial glia cells • Embryonic microglia upregulate MERTK and AXL in response to exogenous insults • Embryonic microglia show a remarkable responsiveness to insults during gestation Summary Despite a growing appreciation for microglial influences on the developing brain, the responsiveness of microglia to insults during gestation remains less well characterized, especially in the embryo when microglia themselves...