The midbrain, or mesencephalon, is comprised of the tectum and tegmentum.
- Tectum – The tectum is the dorsal surface of the midbrain. It is responsible for auditory/visual reflexes, like jumping when someone slams a door. There are 2 important parts of the tectum:
- Superior colliculi – The top part, which controls the visual reflexes
- Interior colliculi – The bottom part, which control the auditory reflexes
- Tegmentum –
- Periaqueductal gray (PAG) – The periaqueductal gray is the gray matter around the cerebral aqueduct that deals with pain.
- Substantia nigra and red nucleus – There are important components of the sensorimotor system, and play a role in Parkinson’s and dopamine.
