The CNS harbors distinct subsets of macrophages, including parenchymal microglia and macrophages residing at border regions (for example, meninges and the choroid plexus). In this issue of Nature Neuroscience, Van Hove and colleagues elegantly demonstrate the diversity and dynamics of non-parenchymal macrophages and identify a unique microglial subtype within the choroid plexus.
- Sebastian G. Utz
- Melanie Greter