Edinger-Westphal nucleus

Edinger–Westphal nucleus
Section through superior colliculus (unlabeled) showing path of oculomotor nerve. ("Edinger–Westphal nucleus" is not on diagram, but would be near oculomotor nuclei.)
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.
Details
Components	Provides input to Parasympathetic root of ciliary ganglion
Identifiers
Latin	nuclei accessorii nervi oculomotorii
NeuroNames	hier-489
NeuroLex ID	Parvocellular oculomotor nucleus
Anatomical terms of neuroanatomy []

The Edinger–Westphal nucleus (accessory oculomotor nucleus) is the parasympathetic pre-ganglionic nucleus that innervates the iris sphincter muscle and the ciliary muscle.

Alternatively, the Edinger–Westphal nucleus is a term often used to refer to the adjacent population of non-preganglionic neurons that do not project to the ciliary ganglion, but rather project to the spinal cord, dorsal raphe nucleus, lateral septal nuclei,lateral hypothalamic area and the central nucleus of the amygdala, among other regions

Unlike the classical preganglionic Edinger–Westphal neurons that contain choline acetyltransferase, neurons of the non-preganglionic Edinger–Westphal nucleus contain various neuropeptides, such as Urocortin and cocaine- and amphetamine-regulated transcript.

Previously, it had been proposed to rename this group of non-preganglionic, neuropeptide-containing neurons to perioculomotor subgriseal neuronal stream, abbreviated pIII_SG.

However, more recently, a final nomenclature has been determined. Preganglionic oculomotor neurons within the Edinger–Westphal nucleus shall be referred to as the EWpg, and the neuropeptide-containing neurons shall be known as the centrally-projecting Edinger Westphal nucleus, or EWcp.

The paired nuclei are posterior to the main motor nucleus (oculomotor nucleus) and anterolateral to the cerebral aqueduct in the rostral midbrain at the level of the superior colliculus.