Involved in oxygen transport in the brain. Hexacoordinate globin, displaying competitive binding of oxygen or the distal His residue to the iron atom. Not capable of penetrating cell membranes (By similarity). Monomer. Homodimer and homotetramer; disulfide-linked. Widely distributed throughout the adult brain, including cerebral cortex, hippocampus, thalamus, hypothalamus, olfactory bulb, and cerebellum. Belongs to the globin family.