What does the midbrain do?

The midbrain is the top portion of the brain stem, adjoining the diencephalon above and the pons below. It comprises the inferior and superior colliculi (together called the tectum), and the tegmentum, crus cerebri, and substantia nigra (together the cerebral peduncle). It’s involved in vision, hearing, body movement in general, and eye movement in particular.

Some language notes: The Latin word tectum can mean roof or ceiling. Tegmentum is a corruption of tegumentum, which means a covering. The midbrain is also called the mesencephalon, from Greek roots meaning — get this — “midbrain”.