Talk:Suprachiasmatic nucleus

May 2006

I'm happy that there's so much good information here, but the article moves too fast and offers too little background information for a piece within a general encyclopedia. Help from an expert or specialist on the topic would be greatly appreciated. Cathryn 07:59, 28 May 2006 (UTC)

The suprachiasmatic nucleus is one of four nuclei that receive nerve signals from the retina, the other three being the lateral geniculate nucleus (aka LGN), superior colliculus, and the pretectum. The LGN is responsible for passing information about color, contrast, shape, and movement on to the visual cortices. The superior colliculus is responsible for controlling the movement and orientation of the eyeball itself. The pretectum is responsible for controlling the size of the pupil. The suprachiasmatic nucleus is responsible for controlling diurnal rhythms and hormonal changes. (Unsigned comment, 09:56, 28 May 2006 by Cathryn)

"Molecular clock"

"Molecular clock" (cited under Gene Expression) is used incorrectly. This term actually refers to the evolutionary divergence of species based on DNA differences. Consider replacing "molecular clock" with "circadian rhythm" or another appropriate term. (Unsigned comment, 19:24, 6 October 2006 by user:Raetzsch)

I would keep the phrase 'Molecular Clock' as it is commonly used (in both Cell and Nature) in this context. —Preceding unsigned comment added by Jt03 (talk • contribs) 11:49, 15 January 2008 (UTC)

File:HypothalamicNuclei

What in the world is that diagram with all the red, white, and blue boxes? I can't make any sense out of it, and the image behind the boxes is almost completely covered up. I think either the diagram needs redoing, or at least some explanation of the diagram would be useful. But still, thanks for the effort! (Unsigned comment, 02:33, 5 December 2006 by 65.32.190.198)

I have no problem with the picture nor with the text. It is difficult stuff, I think it cannot be explained in a way that affords 'one shot learning'. This is just stuff you should study on. Read it again. Do not glance at the picture, but study the picture. I really want to thank the people that make these sites, they are very informative for someone who wants a quick update on some part of the brain. Of course, you need to know a bit about the brain and about reading brain pictures and reading brain-related texts. Perhaps there should be a link, at the beginning of the page, to some basic introductionary text. Perhaps there should be a link from the caption of the picture like: This is a brain image of ..bla blah and then this link would give you a short course in how to read these diagrammes. (Unsigned comment, 23:18, 4 June 2007 by 82.157.193.179)

Undue weight

The article from Brain Research, (Brain Research 537 from 1990 referred to) is much less emphatic that what is suggested in this text and the neuroscientist who wrote the article understand the limitations of the research they did and refrained from grand announcements as the ones emphasized by the article. —Preceding unsigned comment added by 84.97.232.134 (talk) 01:10, 24 February 2008 (UTC)

You are pointing out a very common failing in a great many Wikipedia articles. You know, like an experiment done on 10 rats in a lab proves something about humans ;-)

You are welcome to rewrite the section! --Hordaland (talk) 10:45, 24 February 2008 (UTC)

Ooops. Now I notice that you already did. Good.--Hordaland (talk) 10:47, 24 February 2008 (UTC)

Destruction of section

I'm lacking a description of real effects (beneficial and non-beneficial) with accidental or non-accidental destruction of the section. It is being hinted at in another article but not fleshed out. (Unsigned comment, 11:28, 25 June 2009 by 124.122.167.88)

I don't understand what you are asking about. Destruction of what section? Hinted at in what other article?

Also, please sign your comments with 4 tildes (~) in a row for signature and time stamp. Thanks. - Hordaland (talk) 13:09, 25 June 2009 (UTC)

Retinal targets

The article currently states: "The suprachiasmatic nucleus is one of four nuclei that receive nerve signals from the retina, the other three being the lateral geniculate nucleus (aka LGN), superior colliculus, and the pretectum." But the ventrolateral preoptic nucleus is at least one other [see Lu et al., (1999) Neuroscience 93:209]. — Preceding unsigned comment added by Whatthefat (talk • contribs) 23:22, 9 December 2010 (UTC)

I went looking for this in the article and found that it's been changed to:

The SCN is one of many nuclei that receive nerve signals directly from the retina.

Some of the others are the lateral geniculate nucleus (LGN), the superior colliculus, the basal optic system, and the pretectum:...

So it appears to be OK now. --Hordaland (talk) 19:22, 16 December 2014 (UTC)

Issues

First this article says that the SCN receives signals from the retina. In the section on ectothermic (cold-blooded) vertebrates it says the SCN gets its signal from temperature cues, but adds that this is poorly understood. In fact the SCN in vertebrates in general (including ectothermic) gets its signals mainly from light-receptors. The idea that temperature has anything to do with it is a novel hypothesis that should not be given undue weight. After all, the function of biological rhythms is to anticipate changes before they occur: light is a "leading indicator" while temperature is usually a "trailing indicator." Zyxwv99 (talk) 00:18, 16 November 2015 (UTC)

Please feel free to edit the article to fix that problem (and any other problem you spot). Looie496 (talk) 13:05, 16 November 2015 (UTC)

missing verb

Many SCN neurons are sensitive to light stimulation via the retina, and [are capable of?] sustainedly firing action potentials during a light pulse (~30 seconds) in rodents.

The fix could also be "sustainedly fire". But probably best is to unpack the claim with more context. — MaxEnt 12:38, 27 February 2018 (UTC)

SCN position unclear in diagram

The second infobox image (the drawing with "bulb of eye" in the corner) has a caption that indicates the SCN is not labeled, but that the diagram illustrates the region. Can someone with subject matter knowledge clarify, on the caption, the SCN's position within the diagram? The hypothalamus is on the bottom of the brain, and the brain sits higher than the eyes. Therefore, I'm assuming the diagram is viewed from below, with the top of the diagram indicating the direction the person is looking. From these data points, plus the lead section indicating the hypothalamus is above the chiasm, I'm assuming we're talking about the bulbous-looking formation below the X in the diagram. That is, the position is explained, and the diagram illustrates the region, but nothing connects the two. The caption should tell us where to look in the diagram. tsilb (talk) 23:44, 28 October 2019 (UTC)

Number of SCN neurons

The article currently cites the SCN having 20,000 neurons - using a Forbes article as a reference. https://www.forbes.com/2009/10/14/circadian-rhythm-math-technology-breakthroughs-brain.html#126551963fa7

This number is from mice, not humans. This is the primary resource cited by the Forbes article: https://www.ncbi.nlm.nih.gov/pubmed/19815775

Humans have bigger brains than mice and therefore more neurons. It should either be clear what species this number refers to, or the correct number of neurons in the SCN should be cited. — Preceding unsigned comment added by 2601:197:800:B880:ED18:7F62:FABD:22C0 (talk) 07:00, 19 January 2020 (UTC)

Wiki Education assignment: Bio 4030 Biological Clocks 2023

This article was the subject of a Wiki Education Foundation-supported course assignment, between 17 January 2023 and 10 May 2023. Further details are available on the course page. Student editor(s): TheLastPlatypus (article contribs).

— Assignment last updated by TheLastPlatypus (talk) 10:24, 11 April 2023 (UTC)