Talk:Cerebral cortex/Archive 1

pink matter?
isn't the brain a light red or pink, not gray. I recall hearing the gray matter as a common misconception
 * The living mammalian brain is redish and soft. After the brains have been preserved they turn a sickly grey/tan color. This is a misnomer true, but it's harmless convention. S e miconscious  •  talk  08:13, 29 January 2006 (UTC)

Please clarify:
"Grey matter is formed by neurons and their fibers, and white matter below the grey matter of the cortex is formed predominantly by nerve fibers interconnecting cortical areas with each other and with subcortical structures."

So, gray matter is formed by "neurons and their fibers", but white matter is formed by "nerve fibers"? Isn't this essentially the same defination?
 * I've tried to clarify the differencs in the opening paragraph. Let me know if it is still unlcear. S e miconscious  •  talk  07:50, 16 February 2006 (UTC)

Formation
I added the section formation because I wanted to include 'cortical plate' which comes up regularly in a lot of papers. Feel free to add to it or edit it Paskari 14:55, 21 February 2007 (UTC) uts...........

cortico-cortical connections
"The main source of cortical stimulation is the cerebral cortex itself: up to 75% of the total connections."

Hi, Could you tell me where you got this number from please?

From my readings in of:

V. Braitenberg and A. Schüz, Anatomy of the Cortex: Statistics and Geometry, NY: Springer-Verlag, 1991.

Douglas, R. and K. Martin, “Neocortex,” in The Synaptic Organization of the Brain, 4th ed., G.M. Shepherd (ed.), Oxford, UK: Oxford University Press, 1998.

they have quoted between 96-99% of fibres are cortico-cortical. Even though for e.g, thalamo-cortical afferents maybe higher in particular layers in general

only 1 in 100 or 1000 are sub-cortical.

I personally don't really know, its just what I've read...

Please let me know where you got this number from?

Thanks Punkterfuge 14:33, 14 May 2007 (UTC)


 * It comes from: "Cortex: Statistics and Geometry of Neuronal Connectivity" by Valentino Braitenberg and Almut Schüz, 1998, ISBN-10: 3540638164
 * Hello again. I re-checked Braitenberg&Schuz 1998, and Shepherd 2004 (synaptic organization of the brain). I was wrong and you were right. The 75% figure is about the connections between pyramidal neurones in the cortex. The complete table is:

connections pyramidal-pyramidal= 85%x85% = 72% connections pyramidal-stellate= 85%x15% = 13% connections stellate-pyramidal= 15%x85% = 13% connections stellate-stellate = 15%x15% = 2%

but nothing is said about the proportion of subcortical connections. However, if found the citation in Shpepherd's (ed) "Synaptic organization", chapter 12 "Neocortex" by Dougals R et al:

"Braitenberg and Schuz (1991) have calculated that only 1 in 100 or even 1 in 1000 fibers in the white matter are involved in subcortical projections"

I changed the article's text accordingly. 128.243.220.41 15:59, 31 May 2007 (UTC)

Martin, Whitteridge, and Somogyi in 1985: citation needed
I added a "citation needed" to the reference to "the models put forth by Martin, Whitteridge, and Somogyi in 1985". A brief search turned up a couple of articles by Martin, Whitteridge, and Somogyi in 1985, but each of these articles had other authors too, and none of their titles seemed to be related to a general cortical processing model. Probably one of these articles is what the author meant, but without an actual citation it's unclear which one. Bayle Shanks (talk) 22:57, 13 December 2007 (UTC)

regenerating brain cells
does any one have some usefull info on restoring brain loss from accedents, ageing, or desiese? im trying to gather links for a biogerentology page.. thanks —Preceding unsigned comment added by Royissick (talk • contribs) 19:58, 15 January 2008 (UTC)

Same as neocortex?
is this the same as the neocortex? can't someone make a general overview of all these things
 * No, I don't think it is. Regards,  Relentless Recusant   [ iTalk  §   iWork  ]  04:38, 20 February 2008 (UTC)
 * This overview is already in the article. Cerebral_cortex Lova Falk (talk) 20:21, 20 February 2008 (UTC)

Neurocongnitive World-View is not the only one, as this article would imply.
Anyone who has studied Neurology, Cognitive Psychology AS WELL AS basic philosophy would know that there are deep and persuasive arguments against the MEAT=SOUL hypothesis cradled by Cognitive Biology. That is to say that: while the senses and the CNS are used in the apperception of the world, that is not equal to the statement that our conciousness IS the firing of our neurons. Any 101 Philo course would tackle this question and raise the observation that the nervous system, including the cortex, performs the task of creating an image for the individual to perceive. However, while such an image is useful, a painting of a bowl of fruit is not a bowl of fruit; perceptions are not the things they perceive. To say so would create a self-invalidating Godel loop. This was a well written article, however, in most contemporary advanced learning institutions when one studies neurobiology the point is cleary made that there is not a  provable  chain of  evidence  to  support the statement  that  conciousness  is  created by the cortex rather,evidence that the cortex is working while the individual has experiences  (EEG, fMRI, PET) is a correlative method not causal! I am not opposed to the article or its information on the whole, but this differention must be made as it results in profound theorhetical and logical consequences. Plutophanes A & D Beckett Αγαθος και Σωφος, Σωφος και Καλος, Καλος  και  Αγαθος (talk) 19:04, 22 February 2008 (UTC)
 * I find that it is not clear which specific parts of the text you are criticizing, e.g., consciousness is in the present version said to play "a central role". It does not say that conciousness is created by the cortex (as you write). &mdash; fnielsen (talk) 23:12, 23 February 2008 (UTC)

Decussation of optical nerves
I think the article needs clarification that the information from the left/right visual field is not really the same as information from the left/right eye, i.e. some of the information from the left eye crosses to the right hemisphere and some of the information goes to the crossing point, but ends up in the left hemisphere. Look at pictures in google or wherever to see what I mean. Nickolai 79.72.143.234 (talk) 11:58, 18 March 2009 (UTC)
 * I know what you mean, but what part of the article needs that clarification? Looie496 (talk) 16:35, 18 March 2009 (UTC)

Question
layer VI sends efferent fibers to the thalamus, establishing a very precise reciprocal interconnection between the cortex and the thalamus What is known about dencity of cortex/thalamus connections in different areas of the cortex? If it is not uniform, what is function of "layer VI" in cortex areas that don`t communicate with thalamus?

Arkadi kagan (talk) 12:52, 30 May 2009 (UTC)

Template:Telencephalon
Does anyone know how to integrate the Telencephalon template into the infobox, as it is on the cerebrum article? I have attempted this and the formatting comes out incorrectly. Exert 16:59, 7 August 2009 (UTC)

Obsolete Name?
I read in my textbook Biological Physiology that the term neocortex is no longer used and that it should now be called isocortex because "The alternative name neocortex --the Greek neos means "new" -- is no longer favored because it implies that this tissue evolved more recently, a supposition for which there is no evidence."

Any thoughts?
 * You're right in principle, but it's also true that the term "neocortex" is still more widely used, even by neuroscientists. We ought to explain the situation in this article:  that isocortex is a better term logically, but there are far fewer people familiar with it. (Please remember to sign your talk page messages by typing ~ at the end.)  Regards, Looie496 (talk) 02:44, 27 September 2009 (UTC)

layer 3
I don't know much on this subject, so I thought I'll ask here. layer 3 is a disambiguation page which points (amongst other things) to this page. Is this likely to be useful? Is it likely that someone will search for "layer 3" expecting to get the 3rd layer of the cerebral cortex? --Muhandes (talk) 14:57, 5 July 2010 (UTC)
 * No, but how likely is it that somebody will search for the term looking for one of the other meanings? (This is not a rhetorical question -- I don't know the answer, and if one of the other meanings is much more likely, the disambig should probably be changed to a redirect.  If on the other hand all are rare, there isn't any need for a change.)  If you say "layer 3" to a neuroscientist, layer 3 of the cerebral cortex is probably what will come to mind. Looie496 (talk) 16:13, 5 July 2010 (UTC)
 * This is actually a simple question to answer - quite likely. I just did ~20 DAB relinks, all were to one of the definitions, which is the one I am personally familiar with. My plan was to replace the DAB with a redirect and a redirect. I just wanted to first make sure the term is not equally likely to come up in other areas, which you just helped me determine. Thanks! --Muhandes (talk) 17:52, 5 July 2010 (UTC)

Laminar pattern?
This seems like an odd title for the section to me. Is there a good reason for this, or could we change it to something like "layers of the cerebral cortex"? Solzhenitsyn1 (talk) 17:16, 25 April 2011 (UTC)
 * There is a general principle in Wikipedia articles not to include the article title ("cerebral cortex") in section titles, but other than that I agree that a better title is possible. Maybe "Layer structure", or just "Layers"?  Several other possibilities seem equally good, though. Looie496 (talk) 17:36, 25 April 2011 (UTC)
 * Ah, I didn't realise Looie, thanks for the heads up. As long as there's no important reason why it should be called "laminar pattern", I'll change it. — Preceding unsigned comment added by Solzhenitsyn1 (talk • contribs) 18:13, 25 April 2011 (UTC)

Dimensions of cortex
Although there is now a section discussion the thickness of the cortex and a brief mention this is "2-4mm" early on, the article does not give typical dimensions of the cortex in humans or other mammals. I'm looking for, but haven't yet found, a good reference. Can anyone add these and give citations? Thanks, P.r.newman (talk) 15:16, 17 June 2011 (UTC)
 * I've added some information, with a source. Looie496 (talk) 17:10, 17 June 2011 (UTC)

Contradictory information about scope of named structures
66.99.96.11 (talk) 14:00, 29 June 2011 (UTC)Victor Broderick

I would like to be proven wrong, but… Having spent hours/weeks searching the internet, and Wikipedia in particular, I find that: The profession seems to be confused about the partitions between mesocortex and allocortex. Mesocortex is defined as external to allocortex, but the components of mesocortex listed are the same as those listed for allocortex. The profession seems to be confused about the partitions between paleocortex and archicortex. Paleocortex is defined as external to archicortex, but the components of paleocortex listed are the same as those listed for archicortex.

Which structures include the olfactory cortex? Which are included BY the olfactory cortex? Is the olfactory cortex just another word for pyriform cortex (or piriform) or do these terms merely refer to highly overlapping complexes? Precisely what is the difference between the pyriform lobe and the pyriform cortex, which are sometimes characterized as synonymous and other times characterized as overlapping? And nobody seems to have a definitive list of the human components of the rhinencephalon.

Various lobes and gyri are claimed to be synonymous by one source and overlapping by the next (though the claimed distinction is never delineated.)

I would expect there to be no consensus on the limbic system (or is it limbic lobe?—One source says the limbic lobe is often confused with the limbic association cortex, but what is that?)

And is the subiculum part of the parahippocampal gyrus (or at least the fornicate gyrus) or is it rather a part of the hippocampal formation? I have seen both claims.

It is OK to say that some but not all experts include this or that structure in a certain complex, but the confusion moves beyond controversy.

Why can’t a single article straighten this all out? I fear it is because the experts themselves don’t know. — Preceding unsigned comment added by 66.99.96.11 (talk • contribs)


 * The term mesocortex is not very widely used; my understanding is that it corresponds to the cingulate cortex. The term allocortex includes the cingulate cortex as well as several other cortical areas that don't have the full structure of isocortex, for example the entorhinal cortex.  The term archicortex refers specifically to the hippocampus.  The term paleocortex includes only the olfactory (piriform) cortex and a couple of neighboring olfactory structures.  Our articles, I see now looking at them, are full of misinformation, such as that paleocortex is intermediate between archicortex and isocortex -- that's nonsense.  I'll take a shot at improving the situation -- thanks for pointing out the problem.  (Note that I have removed some additional questions interpolated into the material above by a different editor without any sort of marks to indicate where they came from.) Looie496 (talk) 00:40, 30 June 2011 (UTC)


 * Let me add that part of the problem is that the terms "archicortex" and "paleocortex" are really out of date. "Archi" means "old", and "paleo" means "very old", but actually the modern understanding is that the hippocampus and olfactory cortex are both equally old; the isocortex may be just as old although it has been very extensively modified in mammals. Looie496 (talk) 00:46, 30 June 2011 (UTC)

Other Animals
Do non-primates have a cerebral cortex?

I think information on the cerebral cortex of other animals should be added to the article, if someone knows about this.

Pagw 15:57, 7 May 2007 (UTC)

I'm pretty sure that all mammals have a cerebral cortex.Phaseinduction 19:50, 9 May 2007 (UTC)

Yes, all mammals have a cerebral cortex, although it looks very different in smaller mammals, having no gyri or sulci (bumps and grooves) and constituting a vastly smaller proportion of the brain as well. Birds and reptiles I beleive also have structures that are evolutionarily/phylogenetically also cortex... It would be good to put a picture of a mouse brain with cortex highlighted, for comparison. PhineasG (talk) 05:14, 29 January 2008 (UTC)

This question also highlights a difference between this article and that on cortical columns, where there is discussion on layering in the reptile brain that is at odds with the assertion in this article that cortex is particular to mammals. Good if that could be clarified. P.r.newman (talk) 10:30, 6 July 2011 (UTC)

Cortical thickness and migraines
The results of the study that showed correlation between migraines and cortical thickness was not reproduced in a larger sample. This result should probably be removed. The study repudiating this result is here:. Any thoughts on my removing it? Efseykho (talk) 18:46, 8 June 2012 (UTC)

Horizontal?
Is there a better word than "horizontal" for how the layers are arranged? I doubt very much that they are oriented normal to the gravity vector. 194.39.218.10 (talk) 09:38, 19 November 2012 (UTC)
 * Hi! As far as I know, "horizontal" is used in textbooks and scientific literature, and therefore it should be used in Wikipedia as well. Even if we personally think it is not such a good idea. With friendly regards, Lova Falk   talk  10:49, 24 November 2012 (UTC)

Confusing Picture
A picture like this is much better in my opinion http://www.coheadquarters.com/coOuterBrain1.htm http://www.indiana.edu/~p1013447/dictionary/cercrtx.htm http://www.proteinatlas.org/dictionary/normal/cerebral+cortex/anatomy+2 Could somebody speak with this people so that we can use their pics or maybe someone to reproduce this kind of picture. Thanks — Preceding unsigned comment added by Zenhabit (talk • contribs) 09:02, 22 April 2013‎
 * Hi Zenhabit, why don't you speak with these people and ask for their permission? With friendly regards, Lova Falk   talk  10:22, 3 May 2013 (UTC)

'We use the metric system' - the people of Earth
Changed inches to millimeters. — Preceding unsigned comment added by 145.18.168.219 (talk) 11:20, 9 August 2013 (UTC)

Hippocampus part of the cortex?
"The phylogenetically more ancient part of the cerebral cortex, the hippocampus, is differentiated in five layers of neurons, while the more recent neo-cortex is differentiated in six basic layers. "

Is the hippocampus really part of the cerebral cortex? I think not but don't know for sure. Anyone? Roadnottaken 00:57, 25 July 2007 (UTC)

I'm not an expert in this feild, I'm just taking an AP Psychology class, but from what I've learned, the Hippocampi are not located within the Cerebral Cortex; they are located within the Temporal Lobes of the Cerebrum. Also, the Hippocampi are too large to fit in with the author of this article's definition of the Cerebral Cortex. He states that it is only 2-4 mm thick in humans, which seems much too small.

--CDel921 (18:40 EDT 10 October 2007)

The hippocampus is, as the article states, a phylogenetically older part of the cerebral cortex, and it and associated structures are therefore sometimes called archeocortex or paleocortex. However, it is not differentiated into five layers, but three. The hippocampi are part of the cerebral cortex, which is the outermost part of the cerebrum, although "cortex" is often used casually to mean the cerebrum as a whole. The whole article needs clarification on divisions of the cerebrum. If I have time I may work on it soon... PhineasG (talk) 05:10, 29 January 2008 (UTC)


 * The hippocampus is definitely part of the cerebral cortex. It is part of the cerebrum and it is cortex; archicortex to be precise, which has 3 layers. This is different from neocortex, and paleocortex, which are all cerebral cortex. — Preceding unsigned comment added by 145.18.168.219 (talk) 11:30, 9 August 2013 (UTC)