Figure 1.

Microglia and newly generated neurons in the neurogenic niche of the adult rat brain. (A–D) Photomicrographs showing four distinct phenotypes of Iba1+ microglia. (E) Image of Iba1+ microglia within the subgranular zone (SGZ) of the hippocampal dentate gyrus 6 months after electrically induced status epilepticus. Arrows mark microglia that express Ki-67, which implicate an ongoing proliferation. (F,G) Retroviral-GFP vector labeling of 7-week-old adult-born neurons in the hippocampus following vehicle or LPS-induced microglial activation. The cell bodies of the newly generated neurons are located in the SGZ and granule cell layer of the dentate gyrus. Their dendritic trees are visible throughout the molecular layer and their axons extend into the dentate hilus and the CA3 region. Modified from Bonde et al. (2006), Jakubs et al. (2008), and Thored et al. (2009).