Pretectum is a structure located in the midbrain. It receives binocular input from the eyes and is involved with the pupillary light reflex .

The pretectum, after receiving binocular input, outputs to the Edinger-Westphal nucleus , which is a pre-ganglionic nucleus also located in the midbrain. The Edinger-Westphal nucleus projects onto the ciliary ganglion , whose output controls pupillary diameter (mydriasis or myosis).

Related topics

• Oculomotor nerve
• Mesencephalon