Talk:Sulcus (neuroanatomy)

Expanding Article

I am an undergraduate psychology student at Nebraska Wesleyan University and will be working with my instructor Michele Petracca and the APS Wikipedia Initiative to improve this article this semester.

These are the articles I am thinking about using to add information to the Sulcus (neuroanatomy) page.

Carlson, N. R. (2013). Physiology of Behavior. Upper Saddle River, NJ: Pearson Education Inc.

Cusack, R. (2005). The intraparietal sulcus and perceptual organization. Journal of Cognitive Neuroscience, 17(4), 641-651. doi: 10.1162/0898929053467541

Davranche, K., Nazarian, B., Vidal, F., Coull, J. (2011). Orienting attention in time activates left intraparietal sulcus for both perceptual and motor task goals. Journal of cognitive Neuroscience, 23(11), 3318-3330. doi: 10.1162/jocn_a_00030

Huntgeburth, S. C. (2012). Morphological patterns of the collateral sulcus in the human brain. European Journal of Neuroscience, 35(8), 1295-1311. doi: 10.1111/j.1460-9568.2012.08031.x

Shultz, S. (2012). The superior temporal sulcus differentiates communicative and noncommunicative auditory signals. Journal of Cognitive Neuroscience, 24(5), 1224-1232. doi: 10.1162/jocn_a_00208

Any suggestions or input along the way would be greatly appreciated. Derek hord (talk) 15:12, 6 March 2014 (UTC)

That'd be great, any expansion of the article is appreciated. I think the sources you name are good, but if you want more help you can check out WP:MEDRS for finding suitable sources. WP:MEDMOS gives a manual of style guideline for how to create articles.

We normally go for mostly secondary sources such as professional textbooks, reviews, and position statements within medicine, but haven't been as strict when it comes to anatomy. I'd still advise for the use of such material over smaller primary sources.

P.S. This article as of now contains a rather long list, it may be preferable to split the list portion into a new article such as Sulci of the human brain CFCF (talk · contribs · email) 20:20, 6 March 2014 (UTC)

Classmate revisions

Good information so far. The pictures are helpful as well. Maybe consider using the Carlson textbook from class for any additional information you may need. I found it to be a helpful resource, and it is also a secondary source. Katelyn0902 (talk) 03:05, 21 April 2014 (UTC)

Hi. From reviewing your article, I think you have some very good information. However, there were a few things that stuck out to me.

• First, I think the last sentence that you include in the introductory section of your article may be better placed somewhere else. I think you were attempting to use this sentence as an example of a sulcus being called something else, but when I was reading over it, it just stuck out as a random fact that didn’t really belong. If you wish to incorporate this sentence into the introductory section, you may be better off by starting the sentence off with “for example,” or “notably.” Otherwise, it may be beneficial to move the information about the exception in the nomenclature to it’s own section.
• Next, I noticed in your individual variation section, your first sentence claims that “the most elaborate overview on this variation is probably an atlas by Ono, Kubick, and Abernathey…” Upon looking at this source, I see that you cited the atlas itself for this claim. My question is, who claimed that this atlas is one of the most elaborate overviews on the variation between individuals? Did a scientific paper claim this? Does the atlas make a self-proclamation that they are the most elaborate? You should cite the reference that makes this claim that the atlas is the most elaborate, rather than expecting the reader to take your word for it. Also in this section, in the last sentence, you state that the “larger sulci are, however…” Instead of saying “larger sulci,” maybe you could find a better phrase, such as “prominent sulci” or “unmistakable sulci,” or “pronounced sulci.” You may also want to elaborate on “it is possible to establish a nomenclature.” You could change this to something as simple as “it is possible to establish a common nomenclature across individuals and species” to clear up what you mean.
• In your next section, “Gyrification across species,” you do not include a reference for your first sentence, which you definitely should do. As a reader, I may be interested in further reading the evidence where you based this fact on, and it would be helpful if the citation was immediately following this claim. In the second sentence, you may want to include a hyperlink to the lissencephalics and gyrencephalics articles if they exist on wikipedia. You may also include a comma or two to break up this sentence. Again, you may also want to include the citation immediately following your third sentence in this section.
• Your brain development section is pretty good, but you may consider expanding it to include more information on brain development.
• Finally, in your notable sulci section, I was confused as to why you chose to include the notable sulci in macaque. I realize that you are showing that the macaque has a simpler sulcal pattern, but I didn't really find the relevance of including this in the article. I’m sure there are plenty of animals that exhibit simple sulcal patterns, but it was unclear why you chose to include this species as the lone species of the article.

Overall, I think your article is pretty good. With these minor changes and some expansion here and there, I think your article would be much better! MSederberg21 (talk) 02:13, 22 April 2014 (UTC)

Comments from WP:ANATOMY

Hi! Thanks for your edits to this article as part of your class project. I've remodelled the article around a standard 'structure' that we try and apply to all anatomy articles on Wikipedia. That structure can be found here: WP:MEDMOS#Anatomy. We use this structure so that all articles can be read more easily, and so that editors have a guide as to what makes up a 'complete' article. Cheers, --LT910001 (talk) 04:13, 23 April 2014 (UTC)

consider dental sulcus

173.61.9.126 (talk) 15:13, 6 January 2016 (UTC)

What is in a sulcus?

If anyone knows what is in a sulcus, that would be useful to add. Could it be cerebrospinal fluid? Or extracellular matrix (hyaluronic acid hydrogel)? Or neurons of some kind? Alan U. Kennington (talk) 15:35, 20 October 2024 (UTC)

Hello Alan U. Kennington - the gyrification page might be of help. The sulci give the folds of the cortex enabling the much greater surface area to fit into the cranium. The sulci are the folds of the cortex of the same neural cortical layers. A sulcus is formed by the downward continuation of a gyrus and the ascending part of the next gyrus there is nothing between them. A bit similar to a walnut's surface. Hope that helps.--Iztwoz (talk) 21:28, 20 October 2024 (UTC)

@Iztwoz Thanks very much. But now I'm really confused by this. The diagrams seem to show space in the crevices, between the sides of the crevices. Numerous diagrams show a real gap between the sides of the "ravine". Like this.

I recently saw a retinotopic map of angles and distance from the retina to V1, and it showed that the majority of the projections ended up on the inner walls of the calcarine sulcus, or something like that. (After an hour of searching, I have given up trying to find the article it was in.)

So now if the two sides of every sulcus are actually touching, they will surely experience a lot of electrical "interference". An EEG even picks up a few microvolts from outside the skull. So the touching superficial (molecular) layer ones of the two sides of the sulcus would surely "interfere"? The grey matter doesn't even have myelination for insulation.

My motivation for asking about this is that I'm interested in the V1 retinotopic map. It seems like half of the map is on each side of the calcarine sulcus. So I was initially thinking that the distance/gap between them would stop interference. But now I wonder how that would work if there is no gap.

Anyway, if you know of any sources of information about what happens between the sides of the sulci and fissures to prevent some kind of interference, I think that could be added to the "sulcus" page. Maybe the surfaces are kept apart by the pia mater?

My main point is that very little is said about the touching sides inside the sulci in the sources I have read. (I'm a complete amateur in this area. So I haven't spent years reading everything.) It mystifies me that no one mentions the issue. Cheers. Alan U. Kennington (talk) 01:48, 21 October 2024 (UTC)

Perhaps I could also just mention Figure 1 in this article:

Rajimehr R, Tootell RB (September 2009). "Does retinotopy influence cortical folding in primate visual cortex?". The Journal of Neuroscience. 29 (36): 11149–52. doi:10.1523/JNEUROSCI.1835-09.2009. PMC 2785715. PMID 19741121.

They say that this image of the human brain is made by fMRI. It shows space separating the sides of the sulci. So now I'm wondering if there are gaps in the sulci in the living brain, but not in brains which have been removed after death. This would also be useful to know because very large numbers of diagrams seem to give contradictory indications of whether there are real gaps in the sulci or not. Alan U. Kennington (talk) 02:45, 21 October 2024 (UTC)

This is a better example of what I was thinking about. See Figure 3.

Andrews, Timothy J.; Halpern, Scott D.; Purves, Dale (1997). "Correlated Size Variations in Human Visual Cortex, Lateral Geniculate Nucleus, and Optic Tract". Journal of Neuroscience. 17 (8): 2859–2868. doi:10.1523/JNEUROSCI.17-08-02859.1997.

This figure seems to show distinct gaps between the sides of the calcarine sulcus. Alan U. Kennington (talk) 03:07, 21 October 2024 (UTC)

Probably needed adding that the pia mater is the thin meningeal layer that closely adheres to the surface of the cortex including the gyri and sulci. Between the pia and the next membrane, the arachnoid mater is the subarachnoid space. Cerebrospinal fluid circulates and is pulsated throughout this space to reach all parts of the cerebrum.(Haven't looked at the images yet) --Iztwoz (talk) 03:59, 21 October 2024 (UTC)

@Iztwoz It seems that you have answered my question. In the gaps, there is cerebrospinal fluid. But if all outer surface regions of the cerebrum require the cerebrospinal fluid to flow around them (for whatever reason), then somehow a space must be kept between the "touching" surfaces of the arachnoid mater. I think that it would be useful to have an explanation of all of these points on the Sulcus wikipedia page. Alan U. Kennington (talk) 04:20, 21 October 2024 (UTC)

Bit by bit, I'm getting this. The subarachnoid space is shown as quite thick in the book which I just received in the post one hour ago. (Six more books on the brain are due to arrive this week!) This is the reference.

Per Brodal (2004). The Central Nervous System: Structure and Function. Oxford University Press US. p. 89.

This says pretty much the same as the subarachnoid space wikipedia page. But it shows a really thick space in their diagram. My conclusion from all of this is that there are regions where the sides of the sulcus touch, and others where the sides have a gap. But it doesn't matter because the cerebrospinal fluid is in the subarachnoid space, which is wrapped around the cerebral cortex. This would be really good to describe on the Sulcus page! Alan U. Kennington (talk) 04:33, 21 October 2024 (UTC)

Now my latest understanding of what fills in the gap between two sides of a sulcus is that it is the dura mater. Diagrams on that page and on the meninges page, and page 90 of the 2004 edition of the Per Brodal book, all show the dura mater filling in the gap between sides of a sulcus. I'm not sure if this might only be for substantial fissures. I'm guessing that not all sulci are significant enough to have that dura mater fill in the gap. Alan U. Kennington (talk) 05:23, 21 October 2024 (UTC)

Nope. I've got it wrong again. The dura mater separates the sides of the sulcus only when it is the fissure between the hemispheres, according to meninges#Dura mater and falx cerebri. So it has to be the two arachnoid mater layers, which must be touching sometimes, and otherwise are separated by something else. I wonder if I am the only one who is confused by this. Alan U. Kennington (talk) 05:47, 21 October 2024 (UTC)

Definitive answer. From two sources, I now have a definitive answer. Both the Per Brodal book (2004, page 89) and the arachnoid mater#Structure wiki page say the same thing.

The delicate arachnoid layer is not attached to the inside of the dura but against it and surrounds the brain and spinal cord. It does not line the brain down into its sulci (folds), as does the pia mater, with the exception of the longitudinal fissure, which divides the left and right cerebral hemispheres. Cerebrospinal fluid (CSF) flows under the arachnoid in the subarachnoid space, within a meshwork of trabeculae which span between the arachnoid and the pia.

So the answer finally is that the gap of a sulcus contains cerebrospinal fluid in the middle (subarachnoid space). And to the left and right of this are the pia mater layers. And then the grey matter etc.

So to jump from one molecular layer 1 to the layer 1 on the opposite side, one would travel through a pia mater, some subarachnoid space, and then the pia mater of the other side.

In electrical terms, that looks like there could be some kind of interactions between the sides of the gap. The Rajimehr et al article seems to suggest that the sulcus convexity and retinotopic maps are related. It makes me wonder if this implies some sort of interaction "across the gap" of the sulcus. This is related to my motivation for pursuing this question. Alan U. Kennington (talk) 07:44, 21 October 2024 (UTC)

I've never given any thought to the actual spacing. Have found a couple of articles which I hope to add from soon. Thanks --Iztwoz (talk) 11:13, 21 October 2024 (UTC)

How the sides of a sulcus maintain separation and CSF flow.

@User:Iztwoz The sulcus page keeps getting better (because of your efforts), but I'm still a tiny bit stuck on one issue, namely the mechanism for keeping the sides of each sulcus separated by enough distance to allow the cerebrospinal fluid to irrigate all of the surface of the pia mater and grey matter etc. If the sides of "the ravine" did touch, there would be negative consequences, I assume, because of lack of irrigation. I've read that the total CSF is about 150mL, and there's about 500mL of new CSF created every day. So that's a fairly big turn-over rate. Clearly the body wants to get the old fluid out of the system pretty quickly.

I've been reading several physical books about this subject in the last couple of days (four of which arrived in the mail this week), and numerous online articles and web pages. They all give nice diagrams of how the arachnoid trabeculae separate the pia mater from the arachnoid mater, including down the longitudinal fissure, but none of the diagrams show what happens for other sulci and fissures.

My conjecture now is that the arachnoid trabeculae really do not go down into the sulci to keep the sides separated. This sort of follows by basic physics probably. The trabeculae would break under any stress, I think. So the force which keeps sulcus sides separated must be:

1. the attachment of the gyrus surfaces to the arachnoid mater by the arachnoid trabeculae and other "attachments", and
2. the semi-rigidity of the grey and white matter within the gyri.

When a brain is dissected, the sides of the sulci always appear to touch. But I think that probably in vivo the rigidity of the extracellular matrix hydrogel would give the brain enough "solidity" to maintain separation of sulcus sides. So that makes me think that in some areas these "cisterns" don't have trabeculae in them.

Now all I need is some published literature to either confirm or clobber my conjectures. Alan U. Kennington (talk) 09:21, 23 October 2024 (UTC)

Now I have read an article (free access) which seems to very clearly say that the arachnoid trabeculae go all the way into the sulci.

Benko, Nikolaus; Luke, Emma; Alsanea, Yousef; Coats, Brittany (2020). "Spatial distribution of human arachnoid trabeculae". Journal of Anatomy. 237 (2): 275–284. doi:10.1111/joa.13186.

On page 283, they give numerous details of measurements of "volume fraction" (VF) of arachnoid trabeculae in the subarachnoid space within the sulci and over the gyri. This fraction was around 20% to 30% in the sulci, which was more than on the gyri. The article also mentions the important role of the arachnoid trabeculae in maintaining the relation of brain to skull in case of "traumatic brain injury". So it seems that the AT are important for maintaining distances, which in particular implies that it is the AT which maintains the spacing within the sulcus.

I won't add any of this to the sulcus or subarachnoid space pages until someone can verify that I have understood the article correctly. Alan U. Kennington (talk) 16:09, 23 October 2024 (UTC)

After studying the Benko et al paper much more closely (for a couple of hours), it is not at all clear if they are saying that the arachnoid trabeculae go deep down into the sulci. In half of the paragraphs where they mention sulci, it seems that they assert that they do go down deep, and in the other half, it seems that they don't. Just the basic physics of the situation doesn't seem to imply one or the other either. Alan U. Kennington (talk) 09:53, 27 October 2024 (UTC)

Have just changed the ref you gave on Arachnoid mater page for one by Peng. This seems to be a much clearer account of the meninges. It states that the pressure of the CSF in the subarachnoid space forces the arachnoid mater against the dura mater....As detailed on the sulcus page the pia is closely aligned with the surface of the brain and spinal cord - it is attached by way of the trabeculae to the arachnoid. The pia has to follow all the contours of the brain it is a covering membrane - the arachnoid is more aligned with the dura and is stretched across the sulci - the dura and the arachnoid are the protective membranes - the arachnoid mater cannot follow the pia into the sulci (apart from the longitudinal fissure where it is accompanied by the dura) since the dura has to remain as the thicker protective membrane and as Peng states the arachnoid is forced against the dura. Hope that's clearer. Also the differences in the distances between the pia and arachnoid allow for the subarachnoid cisterns.--Iztwoz (talk) 17:04, 27 October 2024 (UTC)

@Iztwoz There are two problems with that. First, the reference which you have substituted for mine does not explain the meaning of "lepto".

Second, my question is about the arachnoid trabeculae, not about the arachnoid mater and pia mater. I already know about those. That's all well known. Every reference says the same thing. What is not at all clear is whether the space between the sides of the sulci is filled with arachnoid trabeculae or not. In other words, the question is as to what is in the "ravines" between the two meninges. In other words, is the layer of arachnoid trabeculae of constant thickness, or does it become thick within the sulci. Alan U. Kennington (talk) 20:27, 27 October 2024 (UTC)

I can only understand that the trabeculae follow the pia since the limiting arachnoid membrane itself is stretched across the gyri and the trabeculae stay attached to the pia. It seems that the diagrams on related pages make this clear. Iztwoz (talk) 21:47, 27 October 2024 (UTC)

@Iztwoz I'll have to investigate this further. The Benko et al article seems to indicate that the reverse happens. Namely, the trabeculae are attached to the arachnoid membrane. So I'll keep on looking into it until I get a definitive statement somewhere. Alan U. Kennington (talk) 23:35, 27 October 2024 (UTC)

Here's some "ascii art" to explain my question about what the arachnoid trabeculae do in a sulcus.

Option 1. The Trabeculae (T) follow the Arachnoid Mater (A), not the Pia Mater (P).
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
T T T T T T T T T T T T T T T T T
PPPPPPPPPPPP        PPPPPPPPPPPPP
           P        P
 Gyrus     P Sulcus P    Gyrus
           P        P
           P        P
           PPPPPPPPPP

Option 2. The Trabeculae (T) span the space between Arachnoid Mater (A) and Pia Mater (P).
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
T T T T T T T T T T T T T T T T T
PPPPPPPPPPPP T T T T PPPPPPPPPPPP
           P  T T T  P
 Gyrus     P T T T T P    Gyrus
           P  T T T  P
           P T T T T P
           PPPPPPPPPPP

Option 3. The Trabeculae (T) follow the Pia Mater (P), but not the Arachnoid Mater (A).
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
T T T T T T T        T T T T T T T
PPPPPPPPPPPPT        TPPPPPPPPPPPP
           PT        TP
 Gyrus     PT Sulcus TP    Gyrus
           PT        TP
           PT T T T T P
           PPPPPPPPPPPP

Option 4. The Trabeculae (T) follow both the Pia Mater (P) and Arachnoid Mater (A).
But the Sulcus is not filled with Trabeculae.
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
T T T T T T T T T T T T T T T T T
PPPPPPPPPPPPT        TPPPPPPPPPPP
           PT        TP
 Gyrus     PT Sulcus TP    Gyrus
           PT        TP
           PT T T T T P
           PPPPPPPPPPPP

I think Option 3 is the least likely. And Options 1 and 2 are the most likely. All of the dozens of diagrams I have seen are for the Falx Cerebri, not for the other sulci/fissures. It is the other sulci/fissures which interest me. Alan U. Kennington (talk) 06:33, 28 October 2024 (UTC)

I also think that option 2 is the most likely - the sulcus is an extension of the subarachnoid space which I think must include the trabeculae. Iztwoz (talk) 09:47, 28 October 2024 (UTC)

@Iztwoz Excellent! I will be very happy if this is correct. It seems logical, but I have found no sources to support it. I'll start another search to see if I can find something. Thanks. Alan U. Kennington (talk) 09:50, 28 October 2024 (UTC)

The trabeculae apparently do fill the sulci

@Iztwoz Now (after a long search) I have found some sources which support your choice of Option 2, the complete filling of each sulcus with trabeculae. I've noticed, though, that the word "cistern" is used with roughly the same meaning as the space within a sulcus. I might be wrong about that.

This kenhub reference is the most explicit that I have found so far.

Subarachnoid space

They say in their section "subarachnoid cisterns" that where the pia and arachnoid mater are "not in close contact", the space expands and "the trabecular network is not so dense or plentiful" as elsewhere. (Hopefully the copyright bot won't flag me for that.) They're talking specifically about variations of depth due to sulci and gyri here, in the same paragraph.

Then there's this high-powered research article about neurosurgery which I downloaded using the wikipedia library.

Naci Balak, "The Sylvian fissure, cistern and arachnoid membrane"

Maybe this is not so relevant. They don't mention trabeculae, but they do mention multiple arachnoid membranes underneath the "outer arachnoid membrane", or something like that. They seem to imply that the trabeculae always span between arachnoid and pia.

A bit more explicit than the Balak article is this one.

Lu, Brusic, Gaillard, "Arachnoid Membranes: Crawling Back into Radiologic Consciousness"

They say on pages 2–3 that the trabeculae do span from arachnoid to pia mater, but then they also say that the trabeculae sometimes form membranes which "divide the subarachnoid space into individual cisterns" and "provide support for neurovasculature that passes through them".

Anyway, I think that this is all pointing towards Option 2. Alan U. Kennington (talk) 12:28, 28 October 2024 (UTC)

---

Just when I thought I had it figured out, now I've finally looked up subarachnoid cisterns. That wikipedia article suggests strongly that all spaces between gyri are called subarachnoid cisterns, which all have just CSF, not trabeculae. No reference is given for the section Subarachnoid cisterns#Structure though. (I suspect that the second sentence of the first paragraph is wrong.)

Probably the only really certain information on this topic will come from a neurosurgeon who knows first-hand what the situation is. Alan U. Kennington (talk) 13:04, 28 October 2024 (UTC)

---

This is now the situation as I see it.

1. The subarachnoid cisterns page seems to be in error in the section "Structure", first paragraph, second sentence. From my reading, it seems that sulci and cisterns are almost mutually exclusive concepts. Some cisterns do adjoin sulci, but they are not co-extensive. If I'm right, that unsourced sentence on the subarachnoid cisterns page needs to be corrected.
2. Sulci do contain arachnoid trabeculae all the way from the arachnoid mater down to the pia mater, as in Option 2 above.
3. Subarachnoid cisterns (apparently) do not contain arachnoid trabeculae. But they do contain cerebrospinal fluid.

So one could almost say that the cisterns are defined as spaces between the pia mater and arachnoid mater which do not contain arachnoid trabeculae. Alan U. Kennington (talk) 07:21, 29 October 2024 (UTC)

What the French Wikipedia says

It looks like the French web page on this subject completely confirms Option 2.

Espace subarachnoïdien

Here's what they say in French.

Cet espace occupe un faible volume à la surface des hémisphères cérébraux. Au sommet des gyrus, la pie-mère et l'arachnoïde sont en contact étroit, mais dans les sillons séparant les gyrus se trouvent des interstices de forme triangulaire, occupés par le tissu trabéculaire sous-arachnoïdien. Alors que la pie-mère suit de près la surface du cerveau en plongeant dans les sillons, l'arachnoïde forme des ponts de gyrus en gyrus.

Here's my rough translation.

This space occupies a meagre volume at the surface of the cerebral hemispheres. At the summit of the gyri, the pia mater and the arachnoid are in direct contact, but in the sulci separating the gyri there are triangular-form interstices, occupied by subarachnoid trabecular tissue. Although the first follows closely the surface of the brain when plunging into the sulci, the arachnoid forms bridges from gyrus to gyrus.

Most importantly, they are saying that the "trabecular tissue" occupies the triangular interstices in the sulci between the gyri.

This French-language wikipedia article seems to support this.

Arachnoïde

Here's what it says.

Des éléments fibreux et des lamelles enchevêtrées forment un réticulum qui s'étendent à la pie-mère.

It is not so explicit, but it does support it. Here's a rough translation.

The fibrous elements and the tangled lamellae form a reticulum which extends to the pia mater.

That does not explicitly mention the sulci though. Alan U. Kennington (talk) 09:31, 30 October 2024 (UTC)

I have found other articles and will enter edits when I can. But I may start on the other individual meninges page. If you have found citable additions please make the edits.--Iztwoz (talk) 10:54, 30 October 2024 (UTC)

@Iztwoz I have found articles which 95% convince me that the sulci are filled with trabeculae. But there's nothing that I would say is 100% convincing, which would stand up in a court of law as beyond all reasonable doubt! That's why I haven't added any text asserting this yet. Alan U. Kennington (talk) 10:59, 30 October 2024 (UTC)