The Mesencephalon
- The Tectum
The tectum is located in the dorsal region of the mesencephalon, and contains two very important sensory relays, known as the colliculi:
- Superior Colliculi
- The superior colliculi are visual receptors.
- Inferior Colliculi
- The inferior colliculi are auditory receptors.
- The Tegmentum
The tegmentum is located in the ventral region of the mesencephalon, and contains several important systems:
- Reticular Formation
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- Cerebral Aqueduct
- The cerebral aqueduct conducts the third and fourth ventricles. It's important in that it mediates the pain-reducing affect of opiate drugs.
- Periaqueductal Gray
- The periaqueductal gray is the grey matter surrounding the cerebral aqueduct
- Substantia Nigra
- The substantia nigra is an essential sensorimotor system involved in the regulation of movement, especially in relation to the initiation and smoothness of motion.
- Red Nucleus