suprachiasmatic nucleus

noun

su·​pra·​chi·​as·​mat·​ic nucleus ˌsü-prə-ˌkī-əz-ˈma-tik- How to pronounce suprachiasmatic nucleus (audio)
: either of a pair of neuron clusters in the hypothalamus situated directly above the optic chiasma that receive photic input from the retina via the optic nerve and that regulate the body's circadian rhythms

Example Sentences

Recent Examples on the Web This is because the retina is in direct communication with the suprachiasmatic nucleus, which is the part of the brain that schedules the release of hormones assisting in wakefulness (cortisol) and sleep (dopamine). Mackenzie Wagoner, Vogue, 18 Oct. 2022 Tucked within the human brain’s hypothalamus, the suprachiasmatic nucleus (SCN) is responsible for tracking the body’s time. Joshua Hawkins, BGR, 20 Sep. 2022 The suprachiasmatic nucleus is wired directly to the retina, and in the 1980s, it was confirmed that the brain clock could be calibrated by sunlight or artificial light, which signals when it’s daytime. New York Times, 6 July 2022 In 1972, scientists discovered that that cycle is mediated by an area in the brain’s hypothalamus called the suprachiasmatic nucleus. New York Times, 6 July 2022 Our mastermind’s lair is a compartment of the brain called the suprachiasmatic nucleus (S.C.N.), containing only 50,000 of the 86 billion neurons in our body. New York Times, 7 May 2020 For years, the cells of the suprachiasmatic nucleus were thought to be alone in having their own clock, controlling all the rhythms in the rest of the body remotely. Quanta Magazine, 15 Sep. 2015 Just a year later, researchers reported that a tiny patch of cells in the brain called the suprachiasmatic nucleus was necessary for a 24-hour circadian rhythm in mammals. Quanta Magazine, 15 Sep. 2015 The part of the brain that controls circadian timing is the suprachiasmatic nucleus within the hypothalamus. SELF, 4 Sep. 2018 See More

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'suprachiasmatic nucleus.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

Word History

First Known Use

1938, in the meaning defined above

Time Traveler
The first known use of suprachiasmatic nucleus was in 1938

Dictionary Entries Near suprachiasmatic nucleus

Cite this Entry

“Suprachiasmatic nucleus.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/suprachiasmatic%20nucleus. Accessed 3 Dec. 2022.

Medical Definition

suprachiasmatic nucleus

noun

: either of a pair of neuron clusters in the hypothalamus situated directly above the optic chiasma that receive photic input from the retina via the optic nerve and that regulate the body's circadian rhythms
abbreviation SCN
Last Updated: - Updated example sentences
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