The red nucleus is a structure in the rostral midbrain involved in motor coordination. It is pale pink in color; the color is believed to be due to iron, which is present in the red nucleus in at least two different forms: hemoglobin and ferritin. It comprises a caudal magnocellular and a rostral parvocellular part. It is located in the tegmentum of the midbrain next to the substantia nigra. The red nucleus and substantia nigra are subcortical centers of the extrapyramidal motor system.