Section through superior colliculus (unlabeled) showing path of oculomotor nerve.
Figure showing the different groups of cells, which constitute, according to Perlia, the nucleus of origin of the oculomotor nerve. 1. Posterior dorsal nucleus. 1’. Posterior ventral nucleus. 2. Anterior dorsal nucleus. 2’. Anterior ventral nucleus. 3. Central nucleus. 4. Nucleus of Edinger and Westphal. 5. Antero-internal nucleus. 6. Antero-external nucleus. 8. Crossed fibers. 9. Trochlear nerve, with 9’, its nucleus of origin, and 9", its decussation. 10. Third ventricle. M, M. Median line.
The Edinger–Westphal nucleus has two parts. The first is of preganglionic fibers (EWpg) that terminate in the ciliary ganglion. The second is of centrally projecting cells (EWcp) that project to a number of brainstem structures.[5][3][6]
Previously, it has been proposed to rename this group of non-preganglionic, neuropeptide-containing neurons to perioculomotor subgriseal neuronal stream (pIIISG).[9] It has also been suggested that the preganglionic oculomotor neurons within the Edinger–Westphal nucleus be referred to as the EWpg, and the neuropeptide-containing neurons be known as the centrally-projecting Edinger Westphal nucleus, or EWcp.[6]
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The EWN receives feedback from the locus coeruleus about illumination of the retina in order for the EWN to adjust the size of the pupil in response to varying ambient brightness.[3]
Research
It has also been implicated in the mirroring of pupil size in sad facial expressions. When seeing a sad face, participants' pupils dilated or constricted to mirror the face they saw, which predicted both how sad they perceived the face to be, as well as activity within this region.[11][12]
^Haines, Duane (2018). Fundamental neuroscience for basic and clinical applications (Fifth ed.). Philadelphia, PA: Elsevier. p. 188. ISBN9780323396325.
^Kozicz, T. (2003). "Neurons colocalizing urocortin and cocaine and amphetamine-regulated transcript immunoreactivities are induced by acute lipopolysaccharide stress in the Edinger–Westphal nucleus in the rat". Neuroscience. 116 (2): 315–20. doi:10.1016/S0306-4522(02)00772-8. PMID12559087. S2CID11251849.