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a narrow, transversely oriented rostral zone of the mesencephalic tectum, bounded caudally by the superior colliculus, rostrally by the habenular trigone, and laterally by the pulvinar thalami; the pretectal area contains several nuclei that receive fibers from the optic tract; it has bilateral efferent connections with the Edinger-Westphal nucleus of the oculomotor nuclear complex by way of which it mediates the pupillary light reflex.
Either of the midbrain structures located anterior to the superior colliculus. Each pretectum contains several nuclei including the pretectal olivary nucleus, the nucleus of the optic tract and the anterior, medial and posterior pretectal nuclei. A small number of retinal fibres leave the optic tract before the lateral geniculate bodies and synapse mainly in the pretectal olivary nucleus and in the nucleus of the optic tract. Axons from the pretectal olivary nucleus project to the Edinger-Westphal nuclei. Neurons in the pretectal olivary nuclei are involved in pupillary constriction. See pupil light reflex; tectum of the mesencephalon.