[TA] a shallow depression, of a blue color in the fresh brain, lying laterally in the most rostral portion of the rhomboidal fossa near the cerebral aqueduct; it lies near the lateral wall of the fourth ventricle and consists of about 20,000 melanin-pigmented neuronal cell bodies the norepinephrine-containing axons of which have a remarkably wide distribution in the cerebellum as well as in the hypothalamus and cerebral cortex. SYN: locus cinereus, locus ferrugineus, substantia ferruginea.
