The midbrain is the most rostral region of the mammalian brainstem
, caudally adjoining the pons
and rostrally adjoining the diencephalon. Notable structures of the midbrain include: substantia nigra
, ventral tegmental area, part of the red nucleus, the dorsal and ventral raphe nuclei, the midbrain reticular formation, and the superior colliculus. The midbrain, along with the cerebellum
, develops from the mesencephalon, differentiating it from the rest of the brainstem, which develops from the rhombencephalon.