Pretectal area

The pretectum, also known as the pretectal area, is a region of neurons found between the thalamus and midbrain. It receives binocular sensory input from retinal ganglion cells of the eyes, and is the region responsible for maintaining the pupillary light reflex.

Outputs
The pretectum, after receiving binocular input, outputs to the Edinger-Westphal nucleus in the midbrain,
 * to the Cilio-spinal nucleus (Budge), which is located in the VIII cervical and I, II thoracic vertebral segments,
 * and to the nucleus of the posterior commissure.

The Edinger-Westphal nucleus projects onto the ciliary ganglion, whose output controls pupillary constriction (miosis).

The Edinger-Westphal nucleus controls the Pupillary sphincter muscle (used in situations of bright light to reduce the exposure of the retina) and the Ciliary muscle (used for eye focusing and accommodation).

The Cilio-Spinal Nucleus projects onto the superior cervical ganglion, and controls the Pupillary dilator muscle (used in situations of near dark, to increase the exposure of the retina)