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This is an old revision of this page, as edited by 79.168.11.181 (talk) at 23:13, 15 December 2011 (needs a section about age). The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.

Some room for endocannabinoids?

I'm no expert, but is this article appropriate for information regarding the endocannabinoid system? It's a chemical used by neurons, but I don't know enough about it to know if it should be classified as a neurotransmitter, or if it acts in another capacity, or if it isn't really germaine to this article. Well, if someone smarter than me knows, maybe you can let us know. Thanks. Rhetth 20:12, 15 October 2007 (UTC)[reply]

Technically, no, the endocannabinoids are not neurtransmitters, but rather neuromodulators. The distinction is a fine one, and based around where and how the chemical in question is produced and stored. It may fit in here. I'll take a look - there's presently no section for neuromodulators, and the only discussion of neurotransmitters is in classification of neurons by which neurotransmitters they produce. This article could probably use such a discussion. -Corvana (talk) 03:37, 22 December 2010 (UTC)[reply]

This picture must go in this article

I'm no expert on wikianything, and I would go in and add this image directly, but I don't know how to do it and make it look decent. Here's the picture: http://upload.wikimedia.org/wikipedia/commons/d/d0/Complete_neuron_cell_diagram.svg It's a featured image, and it visualizes a couple dozen essentials about the nerve cell. I don't know why it's not already on this page. —Preceding unsigned comment added by Ornen (talk • contribs) 21:21, 19 October 2007 (UTC)[reply]

I agree that the diagram is very useful. For now, I've added it at the end, but I wouldn't object to seeing it integrated earlier. --Arcadian 01:11, 20 October 2007 (UTC)[reply]

Law of Dynamic Polarization Described Backwards?

In the section titled "The neuron doctrine", there is this text, "the Law of Dynamic Polarization, which states that neural transmission goes only in one direction, from dendrites toward axons". Shouldn't that be "from axons toward dendrites"?

Gruhl (talk) 19:04, 19 November 2007 (UTC)[reply]

I believe you are right, it is backwards if it is reffering to communication BETWEEN two cells. If it is reffering to transmition WITH IN a cell, then it is correct; however, it is need of clarification. If no one proves that it is right the way it is writen, i'll change it in a couple of days. --Marvuglia (talk) 20:58, 19 November 2007 (UTC)[reply]

Like "transmission of signals between neurons goes in one direction" ? X10 (talk) 23:59, 18 February 2008 (UTC)[reply]

Clarified Richwil (talk) 10:49, 19 October 2008 (UTC)[reply]

this article is to important to be so brief,,

if some one could add sections for different types of neurons, ex.presynaptic. not really a type but still very important, also need the section as a link to other articles im working on thanks Roy Stanley (talk) 20:41, 15 January 2008 (UTC)[reply]

Number of Neurons vs Synapses for humans

One part of the article says 100 billion total cells but then it later says 100 billion synapses. Which is right? —Preceding unsigned comment added by 216.31.250.91 (talk) 03:30, 15 February 2008 (UTC)[reply]

Fixed: the number for synapses was much too low Richwil (talk) 10:51, 19 October 2008 (UTC)[reply]

maybe a little more serious and scientific than the cited ones: Gerd Kempermann: Adult neurogenesis: stem cells and neuronal development in the adult brain. Oxford University Press, New York 2006.

-- 89.247.127.232 (talk) 10:46, 12 March 2008 (UTC)[reply]

confusing numbers

the numbers of synapses in the human brain are hugely different between this artical and this one: http://en.wikipedia.org/wiki/Synapse so witch one is it? —Preceding unsigned comment added by 69.4.149.231 (talk) 05:25, 16 April 2008 (UTC)[reply]

Fixed: there are many more synapses than neurons Richwil (talk) 10:17, 19 October 2008 (UTC)[reply]

a comprehensive one in simple english please?

i'm not a person who study a lot about humans anatomy, but anyway all the explanations in the article and its associated ones are somehow not easily been captured to the common readers. i mean readers without scientific knowledge like me.

so, to enhance the interactions here between the science editors and the common readers, someone should put the simpler words for easy basic understandings, more direct approach & less scientific explanations that only among the specific group of scholars like scientists, medical field would understand. "e=mc^2", although it's a famous but somehow a notorious formula that doesn't mean everyone understand what does each of these variables do. i believe you got the ideas now. i think i gave my tips already for useful approach to wikipedia.

Is there a particular section you find difficult to understand? Xargque (talk) 22:01, 7 April 2009 (UTC)[reply]

All-or-none principle

There seems to be a large contraction in this section:

  • All-or-none - if a neuron responds at all, then it must respond completely - similar to a boolean function; verses
  • greater intensity of stimulation produces more impulses per second

So what is it? Digital or Analogue?



Xmlv (talk) 15:24, 21 April 2008 (UTC)[reply]

Natural (and especially biological) systems are analog, and are rarely (if ever) digital. See Action potential for a graph of neuro-electrical activity. The name "all or none" is fairly misleading, since it seems to imply that there are instantaneous changes in voltage intensity/polarity. There aren't. The whole process of nerve transmission is gradual, though it occurs at a speed that seems, at least to us humans, to be instantaneous. Basically, the "all or none" principle is a way of saying that there is either an action potential or there isn't an action potential. This is determined by a cell's threshold voltage, which differs between cells and over time. To reach the threshold voltage, incoming electrical signals are summated (at the axon hillock) either temporally (frequencies of signals) or spatially (number of signals). Fuzzform (talk) 01:00, 9 September 2008 (UTC)[reply]

The two statements are compatible: a neuron fires in an all-or-nothing fashion, the rate of firing increases with increased (excitatory) stimulation. Richwil (talk) 10:21, 19 October 2008 (UTC)[reply]

Organization

This article needs some serious reorganization. It appears to make some attempt at splitting information into the categories of anatomy and physiology, but this is a difficult (and if not impossible, then surely pointless) task. Also, there are sections that clearly should be merged (e.g. # 3 Anatomy and histology and # 8 Histology and internal structure). Fuzzform (talk) 00:37, 9 September 2008 (UTC)[reply]

Agreed, I am very slowly working on it. But I have too many pans on the stove right now, so any one else that would like to give it a shot - please do. Hardyplants (talk) 00:46, 9 September 2008 (UTC)[reply]

Dopamine: excitation vs. inhibition

The claim: "the neurotransmitter dopamine in the striatum have excitatory effects on some target cells, mediated by D1 receptors, and inhibitory effects on other target cells, mediated by D2 receptors" has been disputed, but without citation of specific references. Before this sentence is deleted, I would like to see a list of sources that argue against it. Xargque (talk) 20:54, 5 April 2009 (UTC)[reply]

That would be nice, but I'll just mention that I'm the one who added the sentence, and I'm uncertain enough about it not to oppose the deletion. Those effects are all mediated by second messenger systems, which definitely complicates things. Looie496 (talk) 22:18, 5 April 2009 (UTC)[reply]
I'm the one who made the deletion, and it's a reasonable question. I'll need another day or two to do a search if needed, but I figure I should give a quick answer now. There are two aspects of the claim that have been controversial for some time. The first is whether D1 and D2 receptors are really localized to separate populations of striatal cells, or may be colocalized to the same cells. There are investigators who are really dug in on each side of that view. The other is whether D1 receptors are really excitatory in the striatum (most investigators agree that D2 receptors are inhibitory). There is very little direct evidence for excitatory responses, some evidence for inhibitory responses, and a lot of evidence (as Looie correctly points out) for second messenger-mediated interactions with D2 and other receptors. (I know there have been multiple Society for Neuroscience abstracts disputing the conventional D1/D2 model in recent years, but I'd have to look to see which have been published as full papers.) My point in making the edit was not to claim that the cited review was wrong, but simply that the issue is sufficiently unsettled that it would be best not to present it as the example here. Given that readers come here with little background, I think we really need to stick with statements that are on solid ground, and this one has the potential to be misleading. --Tryptofish (talk) 00:06, 6 April 2009 (UTC)[reply]
Um, I lied. The material was actually inserted by Wegener08, as their only Wikipedia contribution. I only cleaned it up a bit. Doesn't affect this discussion, but I want to set the record straight. Looie496 (talk) 01:57, 6 April 2009 (UTC)[reply]
I'm still curious to see the references disputing this (for my own knowledge if nothing else). Perhaps a better example to illustrate this might be either 1) GABA is excitatory in young neurons, or 2) some metabotropic glutamate receptors have inhibitory effects (most obvious being in the synapse between photoreceptors and bipolar cells in the retina Xargque (talk) 15:05, 6 April 2009 (UTC)[reply]
OK, here are a few references. (Given your background as described on your user page, I'm sure you can find more if you are interested.) For inhibitory D1 effects and cross-talk: Hu et al.. For D1-D2 colocalization: Deng et al., which I think takes a balanced middle-ground position. There is also Dickerson and Waszczak, which maybe has not been published yet in full-length form, which I remember as showing very strong colocalization. Anyway, I think that both of your suggested alternative examples are very appropriate ones, and would gladly support either or both. For now, I'm going to again delete the example, but if you are uncomfortable about that, please let me know. --Tryptofish (talk) 15:42, 6 April 2009 (UTC)[reply]
I went to incorporate the photoreceptor to on- vs. off-bipolar cells as an example of a single transmitter having divergent effects. The problem here is that the transmitter is glutamate, which for a naive audience should be called excitatory only. Similar problem with the example of GABA being excitatory in early development. Maybe just leave it alone in this general article? Xargque (talk) 16:54, 6 April 2009 (UTC)[reply]
Well, there's no urgent need to add a new example, but I think the glutamate one would be OK. It's probably easier to explain than GABA, and it would be perfectly fine to frame it in terms of glu typically being excitatory (via ionotropic receptors), but here being a mix of that and inhibitory (via metabotropic receptors). A general audience can handle that, so long as it is explained. (If you want to take a first stab at it, I'll be happy to take a look at it.) --Tryptofish (talk) 17:01, 6 April 2009 (UTC)[reply]
It's not too hard to find clear examples in invertebrates, such as PMID 1133772. I suspect there are examples of cholinergic cells that activate both nicotinic and muscarinic receptors, but I can't name any off the top of my head. Looie496 (talk) 22:41, 6 April 2009 (UTC)[reply]
I gave it a shot with the glutamate example in the retina. If you guys have suggestions or want to try other examples, go for it. Xargque (talk) 17:34, 7 April 2009 (UTC)[reply]
Good job! I made some copyedits. --Tryptofish (talk) 17:55, 7 April 2009 (UTC)[reply]

Interneurons

The statement " Interneurons connect neurons to other neurons within the brain and spinal cord" it unhelpful. Nearly all neurons connect neurons to other neurons; the point is that they do it within the same region, i.e. they are not projecting. Bilz0r (talk) 02:19, 29 May 2009 (UTC)[reply]

Neuron figure

Maybe the neuron figure can be replaced by this one :

http://commons.wikimedia.org/wiki/File:Neuron-figure.svg —Preceding unsigned comment added by 152.81.13.141 (talk • contribs) 06:48, 28 September 2009

The figure currently in the article has clickable labels. If that one could also be given clickable labels, the question might be worth discussing -- it isn't clear to me which one looks nicer. Looie496 (talk) 15:36, 28 September 2009 (UTC)[reply]

Explanation of removal of new sentence

I am removing the newly added sentence "Neuronal connectivity is an important aspect of brain´s ability to process information", because it doesn't actually say anything more than "neuronal connectivity is important", which is not a good way to introduce a paragraph. I am also reverting the section title back to "Connectivity" in accordance with the MOS principle that section titles should not recapitulate article titles. This is of course open to discussion -- it may well be that a better introductory sentence is needed; but if so, it ought to be one that has some actual information in it. Looie496 (talk) 18:21, 22 November 2009 (UTC)[reply]

I'm OK with that. I was thinking the same things, but decided to see what other editors thought, because it's a new editor. --Tryptofish (talk) 21:32, 22 November 2009 (UTC)[reply]

No see also?

I'm not sure if this is for a reason, but there is not a see also section...it seems like it would be helpful to many?Grouphug (talk) 10:56, 17 March 2010 (UTC)[reply]

The first thing needed in any article is plenty of blue links within the text, and this page has plenty of those. Per WP:ALSO, a see also section is not needed unless there are additional links that are important but do not fit within the text; text links are not repeated there. --Tryptofish (talk) 21:53, 17 March 2010 (UTC)[reply]

History of neuron

Hi I think that a section of "History of neuron" and its origins in evolution should be addressed near the beginning of the article. —Preceding unsigned comment added by 128.40.128.134 (talk) 10:43, 26 May 2010 (UTC)[reply]

There already is a section about History, in the sense of the history of its study. Are you talking about the phylogeny of this type of cell during evolution? --Tryptofish (talk) 15:06, 26 May 2010 (UTC)[reply]
The information is in the nervous system article and I think more properly belongs there, but maybe some sort of pointer somewhere in this article would be appropriate. Looie496 (talk) 22:05, 26 May 2010 (UTC)[reply]

Merge Wide dynamic range neuron into Neuron

This suggestion has been made here. Any objections? There is a lot more to say about WDN neurons, but I won't be expanding the article any time soon. Anthony (talk) 08:22, 12 August 2010 (UTC)[reply]

I'm not convinced that neuron is the right target. How about dorsal horn or spinal cord instead? --Tryptofish (talk) 19:45, 12 August 2010 (UTC)[reply]
How about we leave it where it is? There is an article in it, but I can't get excited about it just now. Anthony (talk) 22:00, 12 August 2010 (UTC)[reply]
I agree with keeping it separate for now. I've removed the merge tag. mgiganteus1 (talk) 22:12, 12 August 2010 (UTC)[reply]

Principal cells?

is there a reason why the term "principal cell" or "principal neuron" never comes up in this article? in my understanding, the main division of neurons are interneurons and principal cells. cf: http://www.scholarpedia.org/article/Interneurons

watson (talk) 21:45, 12 August 2010 (UTC)[reply]

In my experience, "principal neuron" isn't a term used as consistently as "interneuron" is. For example, "projection neuron" is often used similarly. --Tryptofish (talk) 21:52, 12 August 2010 (UTC)[reply]
Agree, although I think it would be reasonable to mention the term if there is a place it fits conveniently. Looie496 (talk) 22:15, 12 August 2010 (UTC)[reply]

Improved citation for cell sizes please?

The current citation for cell sizes (ref 3, Davies, Melissa (2002-04-09). "The Neuron: size comparison". Neuroscience: A journey through the brain. http://www.ualberta.ca/~neuro/OnlineIntro/NeuronExample.htm. Retrieved 2009-06-20) is very weak - it simply states a bald fact ("Most cells range from 0.01 to 0.05 mm in diameter") without any backing or (more usefully) any sense of distribution of sizes by neuron type. Can someone improve this, please? Many thanks. P.r.newman (talk) 11:21, 30 August 2011 (UTC)[reply]

needs a section about age

Needs a section about how age influences the brain, and recent discoveries in brain plasticity, especially in new research and new drugs in AVC patients. --79.168.11.181 (talk) 23:13, 15 December 2011 (UTC)[reply]

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