Editing Suprachiasmatic nucleus (section)

{{Short description|Part of the brain's hypothalamus}}
{{Use American English|date = March 2019}}
{{Infobox Brain
|Name = Suprachiasmatic nucleus 
|Latin = nucleus suprachiasmaticus 
|Image = 
|Caption = 
|Image2 = Suprachiasmatic Nucleus.jpg
|Caption2 = Location of suprachiasmatic nucleus{{brk}}{{midsize|{{em|(in green between [[optic chiasm]] and [[hypothalamus]])}}}}}}
The '''suprachiasmatic nucleus''' or '''nuclei''' ('''SCN''') is a small region of the brain in the [[hypothalamus]], situated directly above the [[optic chiasm]]. It is responsible for [[circadian rhythm|regulating sleep cycles]] in animals.<ref name="Hastings">{{Cite journal |last1=Hastings |first1=Michael H. |last2=Maywood |first2=Elizabeth S. |last3=Brancaccio |first3=Marco |date=August 2018 |title=Generation of circadian rhythms in the suprachiasmatic nucleus |url=https://www.nature.com/articles/s41583-018-0026-z |journal=Nature Reviews Neuroscience |language=en |volume=19 |issue=8 |pages=453–469 |doi=10.1038/s41583-018-0026-z |pmid=29934559 |s2cid=256745076 |issn=1471-0048|url-access=subscription }}</ref><ref name="Hastings2">{{cite journal |last1=Hastings |first1=MH |last2=Maywood |first2=ES |last3=Brancaccio |first3=M |title=The Mammalian Circadian Timing System and the Suprachiasmatic Nucleus as Its Pacemaker. |journal=Biology |date=11 March 2019 |volume=8 |issue=1 |page=13 |doi=10.3390/biology8010013 |pmid=30862123|doi-access=free |pmc=6466121 }}</ref> Reception of light inputs from photosensitive [[retinal ganglion cell]]s allow it to coordinate the subordinate cellular clocks of the body and [[Entrainment (chronobiology)|entrain]] to the environment.<ref name="Hastings" /><ref>{{Citation |last1=Weaver |first1=David R. |title=Chapter 39 - Circadian Timekeeping |date=2013-01-01 |url=https://www.sciencedirect.com/science/article/pii/B9780123858702000391 |work=Fundamental Neuroscience (Fourth Edition) |pages=819–845 |editor-last=Squire |editor-first=Larry R. |access-date=2023-04-25 |place=San Diego |publisher=Academic Press |language=en |isbn=978-0-12-385870-2 |last2=Emery |first2=Patrick |editor2-last=Berg |editor2-first=Darwin |editor3-last=Bloom |editor3-first=Floyd E. |editor4-last=du Lac |editor4-first=Sascha}}</ref> The neuronal and hormonal activities it generates regulate many different body functions in an approximately 24-hour cycle.

The SCN also interacts with many other regions of the brain. It contains several cell types, [[neurotransmitter]]s and [[peptide]]s, including [[vasopressin]] and [[vasoactive intestinal peptide]].

Disruptions or damage to the SCN has been associated with different [[mood disorder]]s and [[sleep disorder]]s, suggesting the significance of the SCN in regulating [[Circadian rhythm|circadian timing]].<ref name=":3">{{Citation |last1=Ma |first1=Melinda A. |title=Neuroanatomy, Nucleus Suprachiasmatic |date=2023 |url=http://www.ncbi.nlm.nih.gov/books/NBK546664/ |work=StatPearls |access-date=2023-04-25 |place=Treasure Island (FL) |publisher=StatPearls Publishing |pmid=31536270 |last2=Morrison |first2=Elizabeth H.}}</ref>