locus coeruleus

noun

locus coe·​ru·​le·​us -si-ˈrü-lē-əs How to pronounce locus coeruleus (audio)
variants or less commonly locus ceruleus
: a bluish area of the brain stem with many norepinephrine-containing neurons

Examples of locus coeruleus in a Sentence

Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
One area in the brain involved in focus is the locus coeruleus–noradrenaline (LC-NA) system, which undergoes changes with age and has been linked in past research to early Alzheimer’s disease. Jenny Lehmann, Discover Magazine, 10 July 2025 The locus coeruleus neurons make substances called trophic factors, which promote the building of neural circuits. Kelyn Soong, Anchorage Daily News, 3 Feb. 2023 Similarly, different types of fibers travel to different places, including a part of the brain called the locus coeruleus. Maddie Bender, Scientific American, 10 June 2021 From there, the vagus nerve’s signals travel to other important brain structures with bewildering Latin names, such as the locus coeruleus and the dorsal raphe nuclei. IEEE Spectrum, 29 May 2015

Word History

Etymology

New Latin, literally, dark blue place

First Known Use

1852, in the meaning defined above

Time Traveler
The first known use of locus coeruleus was in 1852

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Cite this Entry

“Locus coeruleus.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/locus%20coeruleus. Accessed 9 Sep. 2025.

Medical Definition

locus coeruleus

noun
lo·​cus coe·​ru·​le·​us
variants also locus ceruleus
plural loci coerulei also loci cerulei -lē-ˌī How to pronounce locus coeruleus (audio)
: a blue area of the brain stem with many norepinephrine-containing neurons
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