Neonatal rat hippocampal tissue slice double-labeled with Sytox (to label all cell nuclei; red) and IB4 lectin (to label microglia and, incidentally, blood vessels; green).
See: Kurpius et al., "Purines Induce Directed Migration and Rapid Homing of Microglia to Injured Pyramidal Neurons in Developing Hippocampus."Glia. 2007 55:873-884.
Image by Dana Kurpius.