Talk:Neuron/Archive 1

Archive 1

Untitled

I added the sentence about size -- useful for non-biologists to orient themselves to the scale being discussed.

The first sentence of this entry used to read "The basic cells of the nervous systems of metazoan animals, whose job is to transmit and process signals." I took the liberty of changing it, suggesting as it did that the job of metazoan animals is to transmit and process signals. (That's a notion of God that's rather different from any I had previously thought of: suppose that there is a God and that s/he created other beings merely to experience things that s/he can not, and then to report on the experience?)

This is a neutral, objective science article. Please don't input any personal Abrahamic religious belief into it. -intranetusa

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From the article: "Synapses of nerves may be between two axons, two dendrites or an axon and a dendrite." Do we have any biologists, physiologists, MD or other specialist who can confirm this statement is correct? My understanding of recent reading I have been pursuing has the axon as an emitter and the dendrite as a collector. Recurrent connections would thus require a portion of the neurons in the nerve fiber or neuron cluster to be oriented roughly 180 degrees. In my current understanding, for the organic circuitry to function as the statement above implies would require multiple neurons in complex patterns rather than individual axon-axon or dendrite-dendrite pairs. mirwin 01:14 Aug 24, 2002 (PDT)

Here is an article that talks about electrical synapses between adjacent dendrites [1]. I think dendro-dendritic chemcal synaptic connections are fairly rare, but here is an article claiming the existence of dendro-dendritic chemical synapses [2]. Chemical synapses between two axons are not unusual; here is a recent article involving such connections [3]. Some of the important work by Eric Kandel on leraning and memory in Aplysia involves axo-axonic sysapses. See the yellow "facilitating interneurons" making axo-axonic synapses onto the sensory neurone in this diagram [4]. 68.109.166.14 04:37, 7 Dec 2004 (UTC)

It is my understanding that all synapses only occur at the tips of dendrites.

No - I don't think this is true. There can be different kinds of synapses - for example axonal-dendritic are the obvious ones, but there can also be axonal-somatic, possibly somatic-somatic etc. There is no reason why there can't be multiple synapses on a dendrite, axon or soma. There have been quite a few constraints which various researchers have imagined about neurons and their synapses - most have turned out not to be applicable.DaveM

Axons function as a conducting line that may go long distances while dendrites branch from end of the axon or directly from the nerve cell body. Electrochemical signals can only go in one direction for each type of neuron (away from the cell body); in sensory neurons signals are sent from sensory receptors (which are modified neurons), in motor cells a signal propagates from the motor cell neuron to effector cells in muscle. The quoted statement doesn't make sense to me. --mav

• Not much of the above is true (well, DaveM is right, he just didn't go far enough). Synapses can be made between a wide variety of different cell types, and sub-cellular regions. The "classic" synapse is the neuromuscular junction. It is often referred to as a junction or an end-foot, but it is a synapse between a motorneuron axon and a muscle fiber. The "classic" CNS synapse is the axo-dendritic synapse - between the axon of a presynaptic neuron and the dendrite of a postsynaptic neuron. Axons, dendrites, somata of neurons can all act as presynaptic elements in a synapse. Probably other things can as well. Axons, synaptic terminals, dendrites, somata, skeletal muscles, glands, blood vessels, smooth muscles (gut etc.), skin, receptors, and almost any other biological part can act as a postsynaptic element. Combine those into every possible combination, and you get an idea of the anatomical diversity of synapses. Synaptidude 01:22, 11 January 2006 (UTC)

• Lest we not forget that there is an entire morphological feature that seems to be missing from this discussion - dendritic spines. Spines are largely associated with excitatory connections and are most often axo-dendritic. (Inhibitory connections are very often located on the soma.) Sirshane13

I am concerned at the notion that neurotransmitters are hormones - I will have to check up on this. My gut feeling is that this is incorrect. DaveM

The usual definition for a hormone in human medicine is a substance which is produced in one tissue and carried through the bloodstream to another tissue, where it has its physiological effect. The part that may be getting confused is that some substances (e.g. norepinephrine) are both hormones and neurotransmitters. I think it's probably best not to refer to such substances as hormones when you are discussing them as neurotransmitters. -- Someone else 22:13 Nov 19, 2002 (UTC)

So shall we remove the reference to hormones then? DaveM

Just did. It didn't add anything anyway<G>. -- Someone else 22:31 Nov 19, 2002 (UTC)

Correct: neurotransmitters are not considered to be hormones. Synaptidude 01:22, 11 January 2006 (UTC)

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I rearranged things a bit and deleted stuff. The stuff about nerves and the nervous system was up too high given the topic, I thought, and not all of it really germane. Also, I've written long articles on synapses and action potentials, so I felt the paragraphs about those could be pared down. I hope people find these changes agreeable. 168...

100 billions neurons in brains

From WordNet: 1. (1) billion, one million million, 1000000000000 -- ((in Britain) the number that is represented as a one followed by 12 zeros) 2. billion, one thousand million, 1000000000 -- ((in the United States) the number that is represented as a one followed by 9 zeros)

Which billion (US or Britain)? : 100 Billion should be avoided for the standard 10^12 representation

I have seen 100 billion, United States. There are a large number of small neurons in the cerebellum, and I have seen 100 billion as an estimate of cerebellar neurons. 68.109.166.14 04:55, 7 Dec 2004 (UTC)

• • • Yes, what I've always heard is that there are 10^16 neurons in the brain..........and 10^17 of them are cerebellar granule cells. Synaptidude 01:14, 11 January 2006 (UTC) : something wrong! its 10^12 neurons and 10^16 synapses

From http://www.nervenet.org/papers/NUMBER_REV_1988.html : "The average human brain (1350 gm) contains about 85 billion neurons. Of these, 12 to 15 billion are telencephalic neurons (Shariff 1953), 70 billion are cerebellar granule cells (Lange 1975), and fewer than 1 billion are brainstem and spinal neurons. A revision: In a beautiful quantitative analysis of human cortex using the optical disector, Pakkenberg and Gundersen (1997) have shown that the number of neocortical neurons ranges from 15 to 31 billion and averages about 21 billion. Other forebrain structures—primarily the hippocampal region, basal ganglia, and thalamus—are likely to contain an additional 5–8 billion neurons. Total neuron number in humans therefore probably averages 95–100 billion. What is perhaps more remarkable is the normal two-fold difference in neocortical neuron number among healthy adults of normal intelligence." Meduz 16:29, 16 November 2006 (UTC)

I'm adding a ref to that nervenet paper to the article, since Section 8 totally lacks references, and that's a good one for it. MOXFYRE (contrib) 19:24, 12 May 2007 (UTC)

100 trillion connections

Is it certain that there are 100 trillion? Any reference? Multiplying 1000 by 100 billion is not correct, as 100 billion neurons can be connected multiply. It is probably more accurate to say it is possible to have up to 100 billion to the power of 1000 connections or something similar involving factorials. I'll try to find a reference... It seems to vary between 1 trillion and 1000 trillion on the web. 500 trillion is quoted as the norm for adults. I think the number in the article should maybe be changed to 500 trillion? [5]

on the brain page they say each neuron has 25 thousand connections...if that means anything... jess523s

That page is... not necessarily accurate. I'm trying to find good source references for the actual numbers. Semiconscious (talk · home) 07:55, 26 December 2005 (UTC)

• • The rule of thumb I've generally heard is that there are about 10K synapses made on every nerve cell. But this is a number that is hard to pin down Synaptidude 01:12, 11 January 2006 (UTC)

I constantly hear 10^11 neurons, 10^15 synapses. Sirshane13

consistentency would be good here, for instance, under connectivity:

The human brain has a huge number of synapses. Each of the 1012 neurons (1,000 billion, i.e. 1 trillion) has on average 7,000 synaptic connections to other neurons. Most authors estimate that the brain of a three-year-old child has about 1016 synapses (10,000 trillion). This number declines with age, stabilizing by adulthood. Estimates vary for an adult, ranging from 1015 to 5 x 1015 synapses (1,000 to 5,000 trillion). [3]

and at the bottom of page, "neurons in the brain":

The number of neurons in the brain varies dramatically from species to species. The human brain has about 100 billion (1011) neurons and 100 trillion (1014) synapses. By contrast, the nematode worm (Caenorhabditis elegans) has just 302 neurons making it an ideal experimental subject as scientists have been able to map all of the organism's neurons. Many properties of neurons, from the type of neurotransmitters used to ion channel composition, are maintained across species, allowing scientists to study processes occurring in more complex organisms in much simpler experimental systems.

quite the discrepancy!

Neural stem cells

Anyone heard of these?

They are quite a revolutionary discovery, so....I don't see much mention of them in here. I'm looking for information on it as well. Not to mention the neurons' flexibility in rerouting.

This textbook might be useful for you [6]. Check this out [7]. Human neural stem cells [8]. 68.109.166.14 04:55, 7 Dec 2004 (UTC)

From the article:

1. The soma, a relatively fat central cell.

I know v. little about biology, but a neuron is a single cell, is it not. The word 'cell' should be replaced (unless the soma is a seperate cell). SgtThroat 22:51, 19 Dec 2004 (UTC)

I tried to give a better description of the "soma". I'd rather say "neuronal cell body". It is rather disorienting when you follow the link for soma from the neuron page. Memenen 01:07, 20 Dec 2004 (UTC)

I've fixed this by adding a stub at soma_(biology), but I don't know what to write there - I'm not a biologist - maybe you could add something? SgtThroat 13:13, 21 Dec 2004 (UTC)

Brain cell regeneration?

I've heard a few contradicting statements about whether or not brain cells regenerate over time, so I wondered if anyone would be so kind to give me some clarification on it. Also, if they regenerate - do they regenerate faster than they die, or is the amount of brain cells decreasing all the time? Thanks in advance.

• • I think sometimes they can. It depends on the situation. From what I've read, that's a very experimental subject right now. It's also very controversial to try to artificially regernate neurons, because many times the cells used to regenerate neurons are brain stem cells from aborted babies. There is also research to see if hair follicles could be used, which would eliminate the ethical issues. It would be very important if brain cells could regenerate, because so many diseases are a result of destroyed cells that are vital to the brain's existence.

• • • This is a very new discovery but it is confirmed. It should be added

The brain keeps growing throughout childhood and adolescence. The issue is whether adult neurons can regenerate. For the most part, adult neurons cannot regenerate. There are specific types of cells in the olfactory system and in and area of the brain called the dentate gyrus of the hippocampus that do regenerate throughout life. Oddly enough, the rate of regeneration of these cells in the hippocampus regenerate faster with exersice. Scientists are devising strategies to harvest these regenerating neurons and hope to one day use them as neural stem cells to help other brain areas regenerate after injury or illness. Nrets 14:59, 6 January 2006 (UTC)

• • • • Nrets is right. Most of the growth of brain size and weight is not due to an increase in the number of neurons. It can be, ni part, due to the increase in size and volume of the existing neurons. There are some kinds of neurons that do regenerate. But most do not.

• • • • • As far as I know, nerve cells are not derived from aborted babies - unless you want to count rat and mouse babies.Synaptidude 01:10, 11 January 2006 (UTC)

• We should be careful to distinguish between regenerate (as in after injury) or continue growth. The brain show enormous signs of plasticity throughout all stages of life, and even in adults. See Pons 1991, Florence & Kaas, etc. There is an entire body of work especially considering the plasticity of the Somatosensory cortex. The topographic organization of entire cortical regions can be regenerated, though the central debate concerns the precise nature of the growth. It is well accepted that plasticity occurs. Concerning certain types of injury to peripheral nerves, they can also in certain cases exhibit an incredible tendency to regenerate, reforming the original connection (when crushed) and restoring the cortical topography that existed normally (See Florence & Kaas). Sirshane13

• Another interesting point on this topic is to realize that the anonymous comment above is also correct. In fact the number of synaptic connections peaks quite early in life, at which time a process called pruning occurs that keeps connections that are robust and removes neurites (processes of neurons like dendrites and axons) that are not utilized. Sirshane13

Jeanley 04:01, 19 June 2007 (UTC)Since neurons do not regenerate when they die, would it be right to assume the number of neurons in our body are 'fixed numbers' at birth and they only grow in size when our body developed into a full grown adult? User:jeanley

As was mentioned above, neurogenesis is known to occur in the olfactory bulb and in the dentate gyrus subfield of the hippocampus. It may occur elsewhere, I haven't kept up with that literature. But no: the number is not fixed at birth, at least in those two parts of the brain. digfarenough (talk) 01:12, 20 June 2007 (UTC)

Nerve Cell Longevity

What is the average longevity of a nerve cell? That's what I was looking for. (I seem to remember it being that nerve cells shouldn't die, and so their life span would be the life of their organism, but if that's so it should be mentioned I think.)

The "average" longevity of a nerve cell is shorter than the life of organism. But this is more a quirk of the math than a useful measure. Most nerve cells live until their organsim dies. But some die before, and none die after, so the average will be less than the lifespan of the organism. Synaptidude 01:03, 11 January 2006 (UTC)

Cleanup and expansion

I've tried to reorganize, clean up and expand this article. I think it looks better now, but there is still some room for expansion and I'm not entirely happy with the organization. If anybody is interested in collaborating to expand this article please let me know. Nrets 16:28, 19 December 2005 (UTC)

Hello, Nrets, thank you for your work on this article. I was hoping to get a gauge concerning how detailed it should be. There are several important features such as dendritic spines and axon collaterals that I was unable to find any reference to in this article. They should certainly be included. Interneurons should probably be discussed explicitly. The drawing of the "structure of a typical neuron" is quite inaccurate in several regards. That is perhaps a typical motor neuron, and the presence of a Schwann cell as the identifier for the myelin sheath makes that picture a typical PNS neuron but NOT the CNS. As pointed out in the article, myelin in the CNS is created by the oligodendrocytes, and many functional differences exist.

Also, the types of support structures inside neurites includes microtubules and microfilaments, not just neurofilaments. Perhaps something could and should be included about Neurofilament Tangle, which is associated with AD.

These are just a few initial thoughts. What do you think? Sirshane13

I definitely think this article could use more detail. By all means, your proposed additions about axon collaterals and dendritic spines sound great, you should definitely have a go at it. You could stick interneurons (inhibitory and excitatory) somewhere in the functional classification. You could also add a section about intracellular structures specific to neurons like microtubules and filaments, post-synaptic densities, etc. I've been meaning to expand this article but have been incredibly busy of late. Nrets 02:40, 17 November 2006 (UTC)

Other meanings

Neuron is also an unmanned aircraft currently developed by French Dassualt in collaboration with other European partners. See [9]. Perhaps something to add on the page? Filur 07:13, 20 December 2005 (UTC)

Classification

As part of the Neuroscien project, I thought I'd work on this article a bit. I'd like to take issue with the Neuron Classification scheme that is currently listed in the argument. "Afferent" and "Efferent" are not really useful classifications. Neurons are generally both afferent AND efferent at the same time. The usual classification is "Principal" (those that make longer-range connections) and "Interneurons" locally projecting neurons. The types of neurons listed "bipolar, unipolar" etc. is fairly archaic and incomplete. Nonetheless, I know this article represents considerable work from other authors, so I'm going to lay off for a couple of days to see if anyone wants to defend these classification schemes. Synaptidude 01:00, 11 January 2006 (UTC)

• Go forth and update! That's my vote. :) Semiconscious · talk 01:06, 11 January 2006 (UTC)

• In some cases afferent and efferent can be useful terms, even if the same cell can be both. But this is more relevant when talking in terms of neural circuitry rather than neurons per se. Nevertheless, some mention should remain. As far as principal versus interneurons, I think that's something worth adding, although some locally projecting neurons also make long-range connections. Also, I agree that the morphological characterizations are a bit archaic, but are still preserved in most textbooks and again are useful to someone who has never heard of a neuron before. So again, if you find a better classification scheme which retains some functional aspects as well as morphological aspect, I'm all for it. What scheme are you proposing? Nrets 01:42, 11 January 2006 (UTC)

• • At the moment I'm not proposing anything besides 'it should be improved' and hoping to build a consensus. Everything you say above is true. I would think that something along the lines of "The functional and anatomical properties of neurons can take many forms, and may even fall along a continuum of properties. Nonetheless, it is useful to try to classify neurons according to function and/or shape, even if no perfect classification scheme exists. In general, neurons are classified according to the shape of their dendritic trees or their axonal arborization...."

• • I still don't think that afferent and efferent are useful terms when describing single neurons. As you say, they are useful in circuits, but if you are considering a single neuron, it is neither afferent nor efferent. It is, as you know a relative term.Synaptidude 01:23, 13 January 2006 (UTC)

• Granted, efferent and afferent don't make sense in this article. Maybe we can fit these concepts somewhere in brain? Nrets 02:13, 13 January 2006 (UTC)

• I completely agree that afferent and efferent are not standard terms for use in the context of neurons. Especially considering the dendritic arborization and local neural activity that makes those terms almost meaningless. Afferent and efferent have an obvious place in nerves and pathways, which can certainly be made up of long axonal projections. Sirshane13

Neuron count by species

I am looking for a partial list of species by neuron count, neuron density or neurons per kg of body mass. Somegeek 13:17, 21 August 2006 (UTC)

I don't have a ref for what you are asking, but based on your request, you might find the work of Sam Wang at Princeton relevant to what you are looking for. Here's a link to one fo his papers. Nrets 13:48, 21 August 2006 (UTC)

Ted Bullock wrote about this in T. H. Bullock. Revisiting the concept of identifiable neurons. Brain Behav.Evol. 55 (5):236-240, 2000. and chapter 7 of T. H. Bullock. How Do Brains Work?, Boston:Birkhauser, 1993. pkatz 12:16, 22 August 2007 (UTC)

Wikification of opening paragraph

I've done some copy editing aiming at wikifying the opening paragraph, the idea of being to summarise what a neuron is rather than stacking facts on top of each other. I'd welcome comments whether this is a step in the right direction. I dropped the word "morphologically" simply because it's unlikely to be understood by a lay audience. It may be redundant too because the sentence is talking about structure rather than function. I think this paragraph still needs plenty of work. For example what is meant by "classic view". Does this mean what the text books teach? A commonly agreed view? An out of date view? etc.--Saganaki- 03:32, 13 October 2006 (UTC)

Challenges to the neuron doctrine

The contents of this section are a reworded expansion of a section of the same name in the neural doctrine article. I think this section in the neuron article should be moved to the neural doctrine article and replaced with language that points there. Wdfarmer 04:42, 28 November 2006 (UTC)

I don't agree that some of these are challenges to the Neuron Doctrine. I also agree that in any case it should be moved to the article about the Neuron Doctrine. pkatz 12:16, 22 August 2007 (UTC)

I re-added the section. I think it'd be fine if that information were transferred to neuron doctrine and replaced here with a single paragraph, pointing to that page as the main article, but they all seem to me to be criticisms of the neuron doctrine and it does seem relevant to this page to at least mention it. But I don't think simply removing the section and doing nothing else is appropriate. Input from other people? digfarenough (talk) 21:42, 22 August 2007 (UTC)

This paragraph is already present in Neuron doctrine. So, I don't see the point of repeating it here. I think that the information about adult neurogenesis is important, but it's not a challenge to the idea that neurons are the fundamental unit of the nervous system and that they are individual cells. pkatz 12:16, 22 August 2007 (UTC)

It's true that neurogenesis doesn't seem related to the neuron doctrine. I made a change to the article that I hope you agree with. I took the old section "challenges to the neuron doctrine" and moved that to the neuron doctrine page, replacing the "challenges..." section there, because the section from this article had references and was slightly more detailed. I renamed the section in this article "The neuron doctrine" and copied the first paragraph from neuron doctrine into that section, then added a very brief summary of challenges to it at the end (leaving out neurogenesis). I think that's better for the article overall. How's it look to you? digfarenough (talk) 19:37, 25 August 2007 (UTC)

Obfuscation of Opening Paragraph?

At the time I write this, the opening paragraph begins: "Neurons ... are not electrically excitable cells in the digestive system that function to process and transmit information." I don't know what to say about this. To take it seriously, I'd say, the digestive system is entirely irrelevant to the topic, and should not be in the opening gloss paragraph, although something general could be said distinguishing nerve cells from cerebral neurons. But the opening paragraph as it stands is hard to take seriously. Is this vandalism, or am I missing something? As vandalism it seems less than silly. Peter H. St.John, M.S. 14:35, 28 November 2006 (UTC)

Thank you for alerting us to the vandal edit. I have reverted it. You can too, as with experience you will recognize it quickly. The great majority of vandalism is done by anonymous IP address editors. Hu 14:43, 28 November 2006 (UTC)

Two copyright violations

The images NisslHippo2.jpg and NeuronGolgi.png are copyrighted. They are mislabled as NIH on their wikimedia pages. They are in fact propertiy of U.C.Davis and useable for personal or academic but not commercial use and therefore incompatable with the GFDL or CreativeCommons.

If we are to bring this article up to Featured status, this must be addressed.

--Selket 23:53, 25 January 2007 (UTC)

I've replaced one of them with an equivalent with compatible license. Nrets 17:55, 2 February 2007 (UTC)

Deleted image

The images at Brainmaps.org are copyrighted. Just because you zoomed in on it and took a screen shot does not make you the creator of the image. We need to be very carefull on Wikipedia not to inadvertantly infringe on someone's copyright. --Selket 22:50, 3 February 2007 (UTC)

This image is a screenshot and thus in the public domain according to their terms of use. Medlat 23:31, 3 February 2007 (UTC)

Neuron/synaptic memory?

What is the current understanding on how information in the brain is stored? Do neurons themselves have a capacity to store information or is information stored by the pattern of synaptic links? Where can I find out more? Thanks.

Solicitous 06:48, 3 March 2007 (UTC)

You could refer to a textbook or a book meant for a general audience on the subject. A quick answer is (using an informal definition of information): neurons can store information in their activity levels (e.g. membrane potential) for very short periods of time; they can change the ion channels in their membrane (both at synapses and elsewhere) which lasts for longer periods of time. They can also change the neurons that they are physically connected to, which could also be considered information storage. I don't see a mention of plasticity in this article, perhaps that is something to be fixed. digfarenough (talk) 23:15, 7 April 2007 (UTC)

Rodent hippocampus?

The caption for the picture here states: "Golgi-stained neurons in the rodent hippocampus." The information given with the article that houses the actual image states: "Image of Golgi stained neurons in the dentate gyrus of an epilepsy patient. 40 times magnification." Are we to assume that the rodent in question suffered from epilepsy, or has there been some kind of error? --Mal 12:54, 24 March 2007 (UTC)

The user who uploaded that image uploaded 2 other images at about the same time that the author claims his/her own work, both of which specifically say they are from humans. It's safe to say then that that image is from an epileptic human, not a rodent. I've changed the caption to say it is human, not rodent. If anyone thinks it's better to be safe, we could just say "Golgi-stained neurons in a slice of hippocampus" or something. digfarenough (talk) 23:08, 7 April 2007 (UTC)

NEED ENK NEURON

Need ENK Neuron information. endogenous inhibitor of pain. enkephalinergic neuron

artificial neurons section

I removed the section on artificial neurons added by User:Amazedsaint. We already have a page on artificial neurons so I think, if anything, we should link to that page in a "See also" instead of using the section that was added (which was copied from the external link added by Amazedsaint and pointing to Amazedsaint's site), especially since the copied section made reference to other text and code that wasn't included in the article. digfarenough (talk) 17:58, 11 April 2007 (UTC)

Feature Sizes

Can someone put in some typical feature sizes. Not just of the soma, but the axons and dendrites' lengths and diameters (60-100 nm sound right)? The sheaths? This is very important, IMHO, but I can't find numbers for these and anyway I'd rather let an expert do it.

http://www.jcb.org/cgi/content/full/170/2/164-a

(note: I moved this to the end of the page: that is the usual location for adding new sections). Sizes vary a lot depending on the neurons. I think your units are off though, micrometers, not nanometers. Looking at one paper I had handy (Fransen et al., J. Neurosci 2002 -- importantly, this is a modeling paper, but those tend to be easy places to get approximate measurements), for entorhinal cortex pyramidal cells, the soma compartment was about 20 by 15 microns ("height" and diameter as a cylinder) and dendrite compartments were about 1.9 microns in diameter (the dendrite length they used is unlikely to be very accurate, but for completeness, the apical dendrite totaled 300 microns in length and the basal dendrite 100 microns). I have to emphasize again that those are sizes of compartments in a biophysical simulation and so should be taken to be approximations and not real measurements of neurons. The link you posted was also mostly a modeling paper, but I know John White, one of the authors of the referenced paper, and he really knows his stuff, so the lower limit of 0.1 microns they reported is probably reasonable. Knowing his work, the experimental data reported there was probably in entorhinal cortex. That's an order of magnitude away from the diameter of the dendrites used in the Fransen et al. paper. I also checked Golding et al. (J Neurophysiol. 2001). They recorded in CA1 pyramidals and report stimulating as far as around 1200 microns distal to the soma along dendrites, so, at least in hippocampal pyramidals, dendrites must stretch at least that far. They also had a modeling component which featured dendrites that were 1.5 microns, roughly confirming the size used above. I'm not a cellular guy, so that's about the best I can do offhand :) digfarenough (talk) 02:18, 13 April 2007 (UTC)

Purkinje cells--NOT bipolar

I am pretty sure purkinje cells are multipolar...it says bipolar in the caption for the first pic.

Assessment comment

The comment(s) below were originally left at Talk:Neuron/Comments, and are posted here for posterity. Following several discussions in past years, these subpages are now deprecated. The comments may be irrelevant or outdated; if so, please feel free to remove this section.

rated top as high school/SAT biology content - tameeria 14:53, 17 February 2007 (UTC) The article seems fairly complete to me, but I'm no expert on neurology. If the B rating seems wrong, please adjust. - tameeria 19:14, 18 February 2007 (UTC)

Last edited at 19:14, 18 February 2007 (UTC). Substituted at 15:27, 1 May 2016 (UTC)

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)

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)

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)

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)

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)

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)

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

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

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)

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)

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

Hello, The article on neurons (http://en.wikipedia.org/wiki/Neuron) mentions how many connections they have with other neurons. The connectivity section of the article is labelled as needing reliable sources. I found this passage from Principals of Neural Science, 2000:

"The nervous system obtains sensory information from the environment, evaluates the significance of the information, and generates appropriate behavioral responses. Accomplishing these tasks requires an anatomical plan of considerable complexity. The human nervous system is comprised of several hundreds of billions of neurons, each of which receives and gives rise to tens of thousands of connections. Some of these connections are located nearly a meter from the cell bodies of origin."

This quote is from page 294 of the 2000 4th edition of the text. The section is The Neural Basis of Cognition> The Anatomical Organization of the Central Nervous System. There is a later edition but I don't have access to it. The major editor of the book is Eric R. Kandel who won a Nobel prize for Physiology and Medicine for his work on memory.

The quote gives a non-specific number to intimate that different neurons have different numbers of connections, and to get the sense of the vastness of the networking in the brain. the quote above modifies the number of input connections.

Cheers, Rick

67.69.19.250 (talk) 20:26, 6 February 2012 (UTC)

Reference/Bibliography related to adult neurogenesis

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)

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)

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

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)

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)

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)

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)

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)

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)

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)

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)

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)

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)

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)

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)

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)

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)

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)

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)

Good job! I made some copyedits. --Tryptofish (talk) 17:55, 7 April 2009 (UTC)

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)

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)

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)

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)

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)

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)

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)

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)

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)

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)

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)

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)

I agree with keeping it separate for now. I've removed the merge tag. mgiganteus1 (talk) 22:12, 12 August 2010 (UTC)

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)

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)

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)

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)

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)

I would think that might be more appropriate for an article at the organ, rather than cellular, level, such as Human brain. --Tryptofish (talk) 00:29, 16 December 2011 (UTC)

McPherrin cells

I find no references to 'McPherrin cells' as mentioned here, anywhere, even directly in Nature, is it possible for someone to add this citation. JamesGrimshaw (talk) 10:17, 30 January 2012 (UTC)

That's a bit of vandalism added a couple of days ago -- I missed it because it was immediately followed by another vandal edit that was reverted by a bot. Thanks for pointing it out; I have reverted it. Looie496 (talk) 18:38, 30 January 2012 (UTC)

Edit request on 14 February 2012

Hi, Why are a couple of the pictures not embedded in the text? You can click on them and get them on a separate page, but not within the article. Thanks WikiUser54 (talk) 13:52, 14 February 2012 (UTC)

Hi. The {{edit semi-protected}} template is used to request a specific change, not to ask questions or make suggestions. I'm not sure which pictures you are talking about, but two appear to have been improperly formatted. Thanks, Celestra (talk) 15:54, 14 February 2012 (UTC)

Images appear to be incorrect

The first couple of images on the page quite explicitly show Schwann cells as the sole myelination objects. My (admittedly limited) understanding is that Schwann cells are primarily found in peripheral nerves, not CNS (central nervous system) nerves, which are myelinated by oligodendrocytes. Thus, the images depicting CNS neurons as being myelinated by Schwann cells are a bit wrong. The distinction is explained in the text correctly. What would the best approach be to rectifying these errors? My first instinct is to caption the images so as to explain them, but I'm a bit nervous about stepping in on an area I'm not yet expert on. Could someone verify that I'm a) understanding the differences correctly, and b) the appropriate response to change the image caption(s)? Thanks!Cephas Borg (talk) 06:35, 26 October 2012 (UTC)

Thank you for pointing it out, and you are indeed correct. I made an edit to the first image, to make clear that it is a peripheral neuron. The second image already indicates that it is a motoneuron, which already means that it's peripheral. --Tryptofish (talk) 21:22, 26 October 2012 (UTC)

Neural Differentiation

I think that it would be helpful to have a brief section introducing the idea of neural differentiation that links to the cellular differentiation page and includes some of the most recent theories behind the mechanisms of neural differentiation. — Preceding unsigned comment added by 149.43.125.138 (talk) 03:17, 19 March 2013 (UTC)

I absolutely agree. It would need somebody capable of writing it, though. About all I know is that they come from stem cells somehow. Looie496 (talk) 03:55, 19 March 2013 (UTC)

Change with time?

This article discusses how the signals get transmitted in a fixed neural network. Does the neural network change with time to remember new things, or memory is only bound with the set of the currently active neurons? If it does, then how it does so, in what ways, that is, on what this process depends? I think this topic is important enough to discuss it in the article about neurons. Mostly it has to do with how the neuron functions. - 91.122.2.229 (talk) 07:11, 2 July 2013 (UTC)

I agree with you. Our main article on that subject is Neuroplasticity, and I was surprised that we didn't have a link to that page here. For now, I've just added it to the See also section, but we ought to find a way to deal with it in the main text, perhaps per WP:Summary style. We do have a summary-style section dealing with neural coding, and that deals with some of the other aspects of networks. --Tryptofish (talk) 18:21, 2 July 2013 (UTC)

Models missing

The article does not contain any mention of mathematical models of neurons. There are articles Artificial neuron and Biological neuron model but none of them is refered to here. --rtc (talk) 20:18, 28 July 2013 (UTC)

Thanks. For now, I'll link to them in "see also". --Tryptofish (talk) 19:54, 29 July 2013 (UTC)

Vandalism Possibility

Since this page is of interest to a larger group of people, I recommend that it should be Semi-locked to prevent any attemps by new users to vandalise the page. Monnor (talk) 23:42, 23 October 2013 (UTC)

The page is pretty closely watched, so it's unlikely that vandalism would last very long. If the level of vandalism gets to be too much of a nuisance, we can ask for the page to be semi-protected for a while, but at the moment that isn't happening. Anyway, thanks for your concern. Looie496 (talk) 19:22, 24 October 2013 (UTC)

Where are neurons in the body?

Although the article looks generally excellent -- and I know that whole textbooks can be written about the neuron -- but why can't I find anything in the article that tells me all the places in the human body that neurons are found? (Or bodies of other animals.)

Yes, I noticed references to the "central nervous system", muscles, sensory organs and skin, and glands. Are there any parts of the human body where neurons are absent?

I think this general question -- Where in the body are neurons found? -- is so basic that its answer should be specifically included in the article as a separate section. This should include which types of neurons are found in which parts of the body. Several scattered references to this issue do not suffice.Daqu (talk) 15:28, 27 March 2014 (UTC)

Neurons not just ELECTRICALLY excitable

While I think this is an excellent article, the first sentence in it says that "A neuron...is an electrically excitable cell...", which seems to suggests that a neuron is only electrically excited, which I don't think is true. The rest of that beginning section does mention sensory neurons (which are variously excited by touch, pressure, light, heat, etc), but I think the term 'electrically' should be removed, which I will, unless it's desired to retain it.GeezerGeezerGeezer (talk) 05:29, 6 June 2015 (UTC)

Well, electrical excitability is a defining feature of neurons. It's true that some are also excitable in other ways, but the article should be careful not to give the impression that other types of excitability are essential properties of neuron-ness. Looie496 (talk) 12:28, 6 June 2015 (UTC)

How to write "vague recent past" ("ca. 2000"?)

I just edited the sentence about adult neurogenesis from "recent research.." to "research starting around 2002.." The reference is 2002, but I have no idea what the earliest*published hint of adult neurogenesis was.

"Recent" to me would mean "in the last 2-3 years", which obviously isn't true as of 2015. But "ca." (circa) doesn't seem appropriate, and the Circa talk page doesn't have any discussion of "near-present usage". I haven't checked Wiktionary or OED. Jimw338 (talk) 21:36, 4 July 2015 (UTC)

The earliest valid claim for adult neurogenesis is generally taken to be PMID 13860748 by Joseph Altman, from 1962. But most neuroscientists did not accept the observations of Altman and his colleague Shirley Bayer until they were replicated using different methods in the 1990s. Looie496 (talk) 14:03, 5 July 2015 (UTC)

Semi-protected edit request on 5 February 2016

Request to use

Neuron or Nerve cell - Labelled Image

either as one of the side image or as an additional image.

I also request you to visit my github and see if any additional images can be added to the article. DrJanaOfficial (talk) 10:35, 5 February 2016 (UTC)

That's a nice image, but I'm not really keen on adding images just for the sake of finding a use for them. Can you suggest a point in the article where that image would contribute substantially to the reader's understanding? Looie496 (talk) 15:24, 5 February 2016 (UTC)

Not done for now: Feel free to change the |answered=yes parameter to "no" when discussion is completed and you'd like someone to make a change. EvergreenFir (talk) Please {{re}} 19:13, 5 February 2016 (UTC)

Neuro Muscular Junction

Neuro Muscular Junction - Not Labelled

Okay, so I made a different one now, its a 3d image of a neuromuscular junction. What do ya say?--DrJanaOfficial (talk) 14:01, 7 February 2016 (UTC)

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'neurone' or 'neuron'

I came from the article on ALS which is also called Motor Neurone Disease. Is there a rationale for distinguishing between neuron and neurone? --Richardson mcphillips (talk) 16:10, 22 August 2014 (UTC)

It pretty much comes down to WP:ENGVAR. --Tryptofish (talk) 21:00, 22 August 2014 (UTC)

'neurone' should be considered as incorrect. As a native speaker of greek I have to respectfully disagree with OED and people using this form of the word. The reason for the confusion is that in plural, 'neurones' is an exact transliteration from greek, and I have no problem with that form of the word being used. It's similar to 'phenomenon' vs 'phenomena', or 'datum' vs 'data', where the singular and the plural form of the word are not conforming to rules in english. ---Vkehayas (talk • contribs) 15:03, 1 October 2016 (UTC)

Semi-protected edit request on 20 March 2016

The article states, "Neurons do not undergo cell division." New research has proven that this statement isn't true. For example, a recent study from the University of Pennsylvania found that in dogs with inherited blindness, retinal neurons actually go through a period of heightened cell division before succumbing to cell death. (https://news.upenn.edu/news/retinal-cells-die-they-regenerate-penn-vet-blindness-study-finds ) The phrase "neurons do not undergo cell division" should be deleted and replaced with the phrase: "While it was previously believed that neurons do not undergo cell division, recent research shows that they do."

50.233.158.98 (talk) 19:26, 20 March 2016 (UTC)

Done —Skyllfully ^(talk | _contribs) 19:56, 20 March 2016 (UTC)

The cited research paper does not provide enough evidence to support the suggested sentence. The fact that some cells in the peripheral sensory organs of mutant animals are expressing mitotic genes is not enough to substantiate a generalizable claim concerning the whole brain. In fact, the cited study shows that normal retinas do not show this effect. The finding is not necessarily worth mention in a wikipedia article that is of more general interest, in my opinion. However, a sentence such as the following would make more justice to it: "While neurons from most brain areas do not undergo cell division under physiological conditions after a certain developmental stage, mitosis can be induced in some neuronal cell types after mutation of specific genes." --Vkehayas (talk • contribs) 15:51, 1 October 2016 (UTC)

Bring back "Computational power" section

At 12:23, 1 February 2017, VeniVidiVicipedia removed the section titled "Computational power", calling it "vague". I believe that section contained very important and significant information, and I politely request that it be returned to the "Neuron" page. Thank you. — Preceding unsigned comment added by 104.162.23.189 (talk)

citation needed in the connectivity section

I was reading the source for last paragraph on the number of synapses in the human brain. All but one of those sentences are backed up by the [21] citation. The sentence still requiring a source is:

"It has been estimated that the brain of a three-year-old child has about 10^15 synapses (1 quadrillion)."

I'd add a 'citation needed' tag, but this is a protected page. Hope I'm doing this right; it's my first talk item.

ColanR (talk) 20:22, 27 July 2017 (UTC) colanr

Cilia in the brain may be busier than previously thought

I read an interesting article on sciencenews.org about little stubs on cells called cilia, and about how the cilia in nerve cells seem to play a bigger role in the functioning of the brain than previously known. I came to this wikipedia article on neurons to learn more about the anatomy of a nerve cell. All in all I learned a lot, but I also noticed that this wikipedia article doesn't mentioned these cilia at all. It probably should. Here's a link to the sciencenews article.

Gekko513 (talk) 01:59, 26 January 2018 (UTC)

Too many general statements

This article requires significant clean up. Its introduction seems to be heavily based on human neurons, with only cursory mention of "other species". It makes very general claims that aren't even true in the human nervous system. For instance, that neurons produce an all-or-nothing response. This is not universally true of all human neurons, as some of them are graded. Also, there are many species, for example C. Elegans, that only have graded, non-spiking neurons. — Preceding unsigned comment added by Mstachowsky (talk • contribs) 12:21, 25 February 2018 (UTC)

An article on such a high-level topic should be accessible to an educated and intelligent high school student. Please feel free to edit the article to improve it, but also bear in mind the target audience. Neuroscientists already know this stuff; we aren't writing for them. We are writing for people who want to understand what a neuron is. It is important to give a sense of the range of variation, but it is even more important to give a sense of a prototypical neuron, such as a cortical pyramidal cell or motor neuron. Looie496 (talk) 14:14, 25 February 2018 (UTC)

Neuron v Neurone

Hi

Neurone was listed as "British spelling", but it is definitely not.

It definitley was used a lot more, back in 1910, but not now.

This is shown by Ngram ...Neurone v Neuron

I have changed it to "Old British spelling" Chaosdruid (talk) 17:42, 16 August 2019 (UTC)

Thanks Chaosdruid. Despite your username you show surprising insight into the modern spelling and language use :).--Tom (LT) (talk) 00:22, 17 August 2019 (UTC)

Nerve cell

It is the main part of the body 2001:8F8:183D:B59D:F8A2:114B:F49E:F0F8 (talk) 03:52, 14 February 2023 (UTC)

Neurosis

On this page it says 'neurosis' stops in early childhood.

My guess is it should say 'neurogenisis'. 2403:6200:8810:CF7C:4C74:9F68:E139:29E5 (talk) 16:10, 21 April 2023 (UTC)

Lack of citations

There are no any citation in the Introductory part of this article. 212.174.115.197 (talk) 12:48, 15 August 2023 (UTC)