ABSTRACT
Glial cells outnumber neurons almost four-fold in the cerebral cortex, but in other regions (e.g., cerebellum) glia are heavily outnumbered. Overall the glia/neuron ratio in the human brain is thought to be close to one. They mediate functions which support neurons. Several distinct populations of glia are recognized: astrocytes, oligodendrocytes (including Schwann cells), and microglia.
