Talk:Neocortex

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This nugget belongs with Brain, with a redirect there.

I think that there's plenty of information about the neocortex that could be added here instead. For example, an overview of the different types of neocortical cells (pyramidal, chandelier, spiny stellate, aspiny stellate, etc.-- Some good overview papers came out a few years ago, and I'll post some links if anyone is interested.) Also, a note about the evolution of the neocortex (is it sometimes called the "new mamallian brain" because some mammals don't have one?) MisterSheik 22:58, 8 August 2005 (UTC)

I think all mammals have neocortex. Here's[1] an article that mentions "the neocortex of various species, representative of the major subdivisions of mammals". Afaik it's called "new" just because its structure differs from that of the areas of cerebral cortex that are similar in all vertebrates.dsws 20:41, 14 December 2005 (UTC)

• All mammals have neocortex, and some non-mammals do as well maybe. Neocortex is called "new" because it is phylogenetically newer than the rest of the CNS. Neocortex refers to any 6-layered cortex. Semiconscious 21:39, 15 December 2005 (UTC)

Cetacean intelligence#Brain structure claims that the dolphin only possesses 5 layers of the neocortex, but that layers I and VI are present among those. Is one of the six layers then missing in the dolphin? —The preceding unsigned comment was added by Wdfarmer (talk • contribs) 05:00, 29 April 2007 (UTC).

Contents 1 Neocortex still viable? 2 80% of the brain's weight 3 RE: 80% of the brain's weight 4 changed form percent to total number 5 Images 6 male and female brain differences

[edit] Neocortex still viable?

Is the notion of a neocortex still viable? In The Emotional Brain, Joseph LeDoux writes, "Anatomists like Harvey Karten and Glenn Northcutt were showing that so-called primitive creatures do in fact have areas that meet the structural and functional criteria of neocortex...As a result of these discoveries, it is no longer possible to say that some parts of the mammalian cortex were older than other parts. And once the distinction between old and new cortex breaks down, the whole concept of mammalian brain evolution is turned on its head." (100). --Mediaphd 02:00, 18 May 2006 (UTC)

I think the distinguishing characteristic of the neocortex is the six-layer sturcture and presence of neocortical columns, and while earlier mammals may have functional equivalents, they lack these specific structural details Tarcieri 02:20, 10 July 2006 (UTC)

[edit] 80% of the brain's weight

I'm going to go ahead and flag this with {{Fact}}. According to the article:

"In humans [the neocortex] accounts for about 80% of the brain's weight."

However, according to this site:

http://faculty.washington.edu/chudler/facts.html

 Average number of neurons in the brain = 100 billion
 Number of neocortical neurons (females) = 19.3 billion
 Number of neocortical neurons (males) = 22.8 billion

How is it that the neocortex could comprise approximately 20% of the brain's neurons but 80% of its weight?

I'll also go ahead and incorporate that information into the article. Tarcieri 02:20, 10 July 2006 (UTC)

[edit] RE: 80% of the brain's weight

Neurons are not the heaviest part of the brain... Glia weigh a lot too, and there is a great deal of myelination in the neocortex. but citation is still needed.

[edit] changed form percent to total number

I changed the part under anatomy from percentage of neurons in male and females to total number. Writing it as percentage assumes that the average man and the average woman have the same total number of neurons. The citation only talks about the average brain and does not specifiy whether men and women have the same total number of neurons. Correct me if I am wrong.

[edit] Images

Folks, it would be nice if someone could add an image here. I myself always wanted to see what really the neocortex is, but never found an image! —The preceding unsigned comment was added by 200.196.125.95 (talk) 02:52, 15 February 2007 (UTC).

[edit] male and female brain differences

could we remove this reference to different numbers of neocortical neurons in males and females? it is a silly fact (men are larger, and therefore have greater numbers of almost every cell type), and without context could come across as needlessly provocative (especially with the silly comment about "what effects this might have"). —Preceding unsigned comment added by PhineasG (talk • contribs) 06:25, 29 January 2008 (UTC)