The Edinger‐Westphal nucleus: A historical, structural, and functional perspective on a dichotomous terminology

Abstract

The eponymous term nucleus of Edinger-Westphal (EW) has come to be used to describe two juxtaposed and somewhat intermingled cell groups of the midbrain that differ dramatically in their connectivity and neurochemistry. On one hand, the classically defined EW is the part of the oculomotor complex that is the source of the parasympathetic preganglionic motoneuron input to the ciliary ganglion (CG), through which it controls pupil constriction and lens accommodation. On the other hand, EW is applied to a population of centrally projecting neurons involved in sympathetic, consumptive and stress-related functions. This terminology problem arose because the name EW has historically been applied to the most prominent cell collection above or between the somatic oculomotor nuclei (III), an assumption based on the known location of the preganglionic motoneurons in monkeys. However, in many mammals, the nucleus designated as EW is not made up of cholinergic, preganglionic motoneurons supplying the CG, and instead contains neurons using peptides, such as urocortin 1, with diverse central projections. As a result, the literature has become increasingly confusing. To resolve this problem, we suggest that the term EW be supplemented with terminology based on connectivity. Specifically, we recommend that: 1. The cholinergic, preganglionic neurons supplying the CG be termed the Edinger-Westphal preganglionic (EWpg) population, and 2. The centrally projecting, peptidergic neurons be termed the Edinger-Westphal centrally projecting (EWcp) population. The history of this nomenclature problem and the rationale for our solutions are discussed in this review.

Drinking alcohol has sex-dependent effects on pair bond formation in prairie voles

“…In addition, there are known sex-dependent differences in the region-specific production of NPY in rats, where males express more than females in the caudal Arc (56), and in the present study, there was an interaction between the effects of alcohol and sex on Fos-ir neurons in the Arc. Similarly, we observed an increase in the number of cells expressing Fos in the EWcp of males, the main central source of the neuropeptide Ucn1, which is also thought to be involved in stress-coping mechanisms (57). Importantly, the majority of the cells expressing Ucn1 were activated (as seen by coexpression of Fos in alcohol-drinking male voles), and there was no difference in the number of Ucn1-positive cells between treatments, indicating that the greater levels of Fos in the EWcp were due to activation by alcohol and not simply to a greater number of cells in this region.…”

Gata2 and Gata3 regulate the differentiation of serotonergic and glutamatergic neuron subtypes of the dorsal raphe

“…One of these, cocaine and amphetamine-regulated transcript (Cart), encoding for a neuropeptide expressed in the centrally projecting preEdinger-Westphal nucleus located near the ventral midline of the midbrain (Kozicz et al, 2011), was indeed ectopically expressed in some cells of Gata2…”

MicroRNA-326 acts as a molecular switch in the regulation of midbrain urocortin 1 expression

“…This postulate was tested in a stress-sensitive model system, the midbrain urocortin 1 (Ucn1) neuronal system. Ucn1 neurons in the rostroventral midbrain, within the centrally projecting Edinger-Westphal nucleus (EWcp) are sensitive to stress: [17][18][19][20][21] mice lacking Ucn1 reveal anxiogenic behaviour, 22 while depressed suicide completers have upregulated midbrain Ucn1 mRNA expression compared with naturally deceased control individuals. 23 Here, we report that the brain-enriched miR-326 acts as an upstream regulator of Ucn1 during a neuronal stress response.…”