Traditionally, there were four types of glia in the CNS: astrocytes, oligodendrocytes, ependymal cells, and radial glia. Of these, the one type that's most important to the developing revolution in our ideas are those cells called astrocytes.2 It turns out that there are at least two types of cell (at least) subsumed under this name.24, 25, 31, 32 One, which retains the name of astrocyte, takes up neurotransmitters released by neurons (and glial cells), aids in osmoregulation,10 controls circulation in the brain,1, 31 and generally appears to provide support for the neurons and other types of glia.