Detection of warm vs hot

[barfbag]

feeling heat versus feeling something pushing up against you, for example), these have different nerves with dedicated roles

 

 

 

Fun Fact: The body has no nerves designed to feel heat. The nerves can detect cold and they can detect warm, but not heat.

 

The heat sensation comes when something is so hot it can stimulate both the warm and cold receptors at the same time.

 

(Note: I have had numerous comments about the use of the word heat here. I mean this to be roughly temperatures above 45 degrees, and shoulkd have said HOT not heat. I also think this is a fairly obvious assumption and it is ridiculous I need to clarify this.

Edited July 16, 2014 by barfbag

[hypervalent_iodine]

Fun Fact: The body has no nerves designed to feel heat. The nerves can detect cold and they can detect warm, but not heat.

 

The heat sensation comes when something is so hot it can stimulate both the warm and cold receptors at the same time.

This seems fairly nonsensical. Would heat and warmth not be synonymous in this sense? Perhaps you could provide a better explanation and source for what you are taking about.

[barfbag]

@ Hypervalent_Iodine,

 

 

barfbag, on 15 Jul 2014 - 8:00 PM, said:

Fun Fact: The body has no nerves designed to feel heat. The nerves can detect cold and they can detect warm, but not heat.

The heat sensation comes when something is so hot it can stimulate both the warm and cold receptors at the same time.

This seems fairly nonsensical. Would heat and warmth not be synonymous in this sense? Perhaps you could provide a better explanation and source for what you are taking about.

 

 

 

This is actually a Science Center center attraction. They have 2 coils close to each other that are in the shape of a hand. It looks like a stove burner but in the shape of a hand.

 

One element is cold to the touch, and the other element is merely warm (not hot).

 

If you place your hand upon this you will feel as if it is too hot to continue, and yet your hand is not exposed to excessive heat.

 

 

http://www.scholarpedia.org/article/Thermal_touch

The sensory system involved in perceiving the changes in skin temperature begins with two kinds of receptor found in the epidermal and dermal layers of the skin known as cold and warm thermoreceptors. These receptors respond similarly to radiant and conducted thermal energy and are involved in the perception of innocuous (harmless) temperatures.

 

mild cooling (25-31 °C) and warming (34-40 °C) of the skin can evoke sensations of burning and stinging as well as innocuous sensations of cold and warmth (Green, 2002)

 

 

 

I hope that satisfies. I am having a hard time using search terms like "hot and cold", and took an extra 20 minutes on this post because I was having search issues.

 

Here is a better "nonsensical" (your word) explanation/demonstration/experiment to try...

http://www.questacon.edu.au/outreach/travelling-exhibitions/perception-deception/exhibits/can-temperature-cause-surprising-sensations

Edited July 16, 2014 by barfbag

[hypervalent_iodine]

IIRC, there are a number of thermo receptors that respond to different temperature ranges (separate to those that detect cold) up to what you would call painfully hot rather than just warm. Above a certain threshold (about 45oC) what you're feeling is mostly pain as a result of thermal nocireceptors, which are different to the types of receptors used to sense temperatures in the 30oC-45oC range. I think that above a certain temperature, the receptors that detect cold have a burst of activity, but it is short lived and different to what you claimed, which is that the combination of the two is what we use to detect heat, which is somehow different to warmth. This seems quite incorrect to me, or you are not wording it correctly.

[iNow]

Fun Fact: The body has no nerves designed to feel heat. The nerves can detect cold and they can detect warm, but not heat.

 

The heat sensation comes when something is so hot it can stimulate both the warm and cold receptors at the same time.

Here's another fun fact: You're talking out of your ass and should probably just be ignored (unless, of course, we're correcting you so others genuinely interested in learning are not led astray).

 

http://en.m.wikipedia.org/wiki/Thermoreceptor

A thermoreceptor is a sensory receptor, or more accurately the receptive portion of a sensory neuron, that codes absolute and relative changes in temperature, primarily within the innocuous range.

<...>

In humans, temperature sensation enters the spinal cord along the axons of Lissauer's tract that synapse on second order neurons in grey matter of the dorsal horn, one or two vertebral levels up. The axons of these second order neurons then decussate, joining the spinothalamic tract as they ascend to neurons in the ventral posterolateral nucleus of the thalamus.

<...>

In mammals, temperature receptors innervate various tissues including the skin (as cutaneous receptors), cornea and urinary bladder. Neurons from the pre-optic and hypothalamic regions of the brain that respond to small changes in temperature have also been described, providing information on core temperature. The hypothalamus is involved in thermoregulation, the thermoreceptors allowing feed-forward responses to a predicted change in core body temperature in response to changing environmental conditions.

 

[barfbag]

@ Hypervalent_ Iodine,

 

which is that the combination of the two is what we use to detect heat, which is somehow different to warmth.

 

 

The difference between hot and warm is measured in temperatures.

 

It is a fallacy if you think Hot Heat ( I'm being made to describe the type of heat as it is obviously not perceivable enough in context) is only detected through the warm thermoreceptors and nocireceptors.

 

I have outlined an experiment where you could experience Heat with only exposing yourself to Warm and Cold. This is caused by a Paradoxical response to heat by the nervous system.

 

You are correct that a third pathway is turned on when this occurs.

 

 

 

I think that above a certain temperature, the receptors that detect cold have a burst of activity, but it is short lived and different to what you claimed

 

 

Okay. Are you saying the science center display should not activate Hot/Burning/pain receptors when your skin is only subjected to warmth and cold?

 

I thought it would be of interest to the OP, but this thread is "too much fun"

 

@ Inow and H_I,

 

Here's another fun fact: You're talking out of your ass and should probably just be ignored (unless, of course, we're correcting you so others genuinely interested in learning are not led astray).

 

 

 

Thanks Inow (was that supposed to be Iknow (curious)). I do not mind talking out of my ass when I am correct, but thanks for being so polite.

 

 

http://www.sciencemag.org/content/265/5169/252.abstract

 

The thermal grill illusion: unmasking the burn of cold pain

1. AD Craig,
2. MC Bushne
3. Division of Neurobiology, Barrow Neurological Institute, Phoenix, AZ 85013.

• Abstract

In Thunberg's thermal grill illusion, first demonstrated in 1896, a sensation of strong, often painful heat is elicited by touching interlaced warm and cool bars to the skin. Neurophysiological recordings from two classes of ascending spinothalamic tract neurons that are sensitive to innocuous or noxious cold showed differential responses to the grill. On the basis of these results, a simple model of central disinhibition, or unmasking, predicted a quantitative correspondence between grill-evoked pain and cold-evoked pain, which was verified psychophysically. This integration of pain and temperature can explain the thermal grill illusion and the burning sensation of cold pain and may also provide a basis for the cold-evoked, burning pain of the classic thalamic pain syndrome. [ color changed by me/bolded/underlined for emphasis of topic]

 

 

 

 

(maybe a nine year oldcan explain it better than me..)

 

NOTE: She suggests an experiment where you cool your hands in the snow and then come inside and put your hands in lukewarm water or beside a low heat. Your hand will feel burning.

 

https://www.youtube.com/watch?v=s25o1ka1WeE

(or this 11 year old)

 

So you can learn this further by trying Thunberg's thermal grill illusion. Soooooo

 

All of this because I made a 3 sentence "Fun Fact" I thought the OP might appreciate.

 

Even though I can show this I am sure I will be found to be "wrong" somehow by you guys..

 

Does anybody ever admit being wrong around here ?

 

@ Inow again/still,

 

 

A thermoreceptor is a sensory receptor, or more accurately the receptive portion of a sensory neuron, that codes absolute and relative changes in temperature, primarily within the innocuous range.
<...>
In humans, temperature sensation enters the spinal cord along the axons of Lissauer's tract that synapse on second order neurons in grey matter of the dorsal horn, one or two vertebral levels up. The axons of these second order neurons then decussate, joining the spinothalamic tract as they ascend to neurons in the ventral posterolateral nucleus of the thalamus.
<...>
In mammals, temperature receptors innervate various tissues including the skin (as cutaneous receptors), cornea and urinary bladder. Neurons from the pre-optic and hypothalamic regions of the brain that respond to small changes in temperature have also been described, providing information on core temperature. The hypothalamus is involved in thermoregulation, the thermoreceptors allowing feed-forward responses to a predicted change in core body temperature in response to changing environmental conditions.

 

 

 

How does this relate in any way to what triggers the sensation of HOT heat? You claim I am talking out of my ass?

Edited July 16, 2014 by barfbag

[iNow]

Three things. First, what you are trying to describe is the sensation of temperature, not heat. They are different. Heat is a transfer of energy wherein temperature is one type of measurement of it. Second, it's not even temperature being perceived by the human body, but instead changes in temperature (either relative or absolute). Third, this is all tangential to the actual thread and is off-topic.

[hypervalent_iodine]

I have requested another mod come in to split these posts.

 

barfbag, as iNow has noted you are not using standard definitions for what you are talking about. You are either wrong in what you are saying or you are simply using words in ways that don't make sense. Could you please define what you mean by warmth and heat and why the two are different?

 

Also, the paradoxical response is not what gives rise to how we perceive extreme temperatures. I have stated that we have different thermo receptors for temperatures above 45oC that are not related to the ones we use to sense cold and you have ignored it, I guess since it doesn't support your claims.

[barfbag]

Isn't Spacial touch something lost during strokes? There is likely some research that helps stroke victims understand sensations.

 

@ Hypervalent_Iodine,

 

If you cannot understand the difference between warm and "Hot Heat" (term I used in post 18 adding Hot in front), then I understand your confusion, Let's say hot heat is roughly 45oC+.

 

My comment in post 13 was about a quote by Metacogitans who said,

feeling heat versus feeling something pushing up against you, for example), these have different nerves with dedicated roles

 

 

Hey Metacogitans.. You can't say feeling heat... (joking for a point, yes you can)

 

I think the dual nature of some nerves could aid someone designing a program attempting to learn (as in OP), but this thread does concern learning "spatially" the locations of feeling. I only mentioned it casually in a three sentence post (which is 100% correct). It has been others dragging this part out.

 

@ Inow,

 

The nerves detect heat because of a transfer of energy. I will say that. How is that not heat.

 

First, what you are trying to describe is the sensation of temperature, not heat. They are different. Heat is a transfer of energy wherein temperature is one type of measurement of it.

 

 

Where to even begin?

 

Before I link 20+ websites...

 

Are you saying (I want to be clear), "People cannot feel heat".

 

@

 

Hypervalent_Iodine,

 

Same question...

as iNow has noted you are not using standard definitions for what you are talking about.

 

 

Before I link 20+ websites...

 

Are you saying (I want to be clear), "People cannot feel heat".

 

 

@ Inow again,

 

If you take a metal ball and a plastic ball from your Freezer which one feels colder? The metal one would. This is NOT because there is a temperature difference. It is because the metal ball is more conductive and TRANSFER ENERGY ( HEAT IS A TRANSFER OF ENERGY) better than the plastic ball. THE SKIN CANNOT DETECT THE TEMPERATURE AT ALL , or else it would know both balls were the same temperature (Which it doesn't).

 

I am surprised by your first point because you said as much in your second point,

Second, it's not even temperature being perceived by the human body, but instead changes in temperature

 

 

When you say "Changes in temperature" do you mean a TRANSFER OF ENERGY?

 

Want a youtube video of little vibrating molecules, because I'm sure there are many?

Edited July 16, 2014 by barfbag

[hypervalent_iodine]

No. I am saying in no uncertain terms that your original statement,

 

Fun Fact: The body has no nerves designed to feel heat. The nerves can detect cold and they can detect warm, but not heat.

 

The heat sensation comes when something is so hot it can stimulate both the warm and cold receptors at the same time.

Is wrong.

[barfbag]

I was trying to be nice, but I do not want to teach.

 

You guys can pretend you are unable to understand this, but I think it's just argumentative.

 

Yeah. I should have said Hot (although I think it is obvious the intent) and not heat.

 

No. I am saying in no uncertain terms that your original statement is false,

 

 

Whew! Because from your post # 20 note, it looked like you had agreed with Inows faulty understanding of heat vs temperature.

Edited July 16, 2014 by barfbag

[hypervalent_iodine]

Oh no, I agree with iNow. You seem have misunderstood what he was saying.

And your statement is still incorrect. We perceive hot temperatures above 45oC with thermo receptors as well, they are just different ones to those we use to detect cooler temperatures.

[barfbag]

@ Hypervalent_Iodine,

 

We perceive hot temperatures above 45oC with thermo receptors as well, they are just different ones to those we use to detect cooler temperatures.

 

 

I think you are describing thermal nocireceptors, and I also think you are confusing the sensation of heat with the sensation of pain.

 

If your car seat is very hot when you sit in it that sensation is not pain. I think nocireceptors transfer signals of pain, and are not used as you describe.

 

NOTE: If you are NOT talking of nocireceptors I apologize and am curious what other nerves are at play here I am unaware of, but I think you must be because there is only the three involved in thermal detection.

 

The mild burning sensation you feel from hot sand or from your hot car seat is NOT pain. It is caused by heat exciting both the warm thermoreceptors and the cold thermorecptors at the same time.

 

I gave an example before that is apt.. Run barefoot in the snow for 10 minutes and then go inside a warm house. It will feel like your feet are on fire. Cold + Warmth (<45 degrees) = Burning sensation.

 

there are a number of thermo receptors that respond to different temperature ranges

 

(from post 4)

 

So how many are we talking about? I say three. Cold Thermoreceptor, Warm Thermoreceptor, and nocireceptors which are used in sensory overload to indicate pain ONLY.

 

What is your number?

Edited July 16, 2014 by barfbag

[hypervalent_iodine]

No, if you read back you'll see I explicitly referred to them as nocireceptors. You claimed that we have no way of detecting heat, which we now have established is to mean temperatures above 45oC. The thermal nocireceptors are activated by temperatures above 45oC or there abouts. We perceive that feeling as burning. So which part of that process means our nerves don't 'detect heat', when that is exactly what they are responding to?

[barfbag]

@ Hypervalent_Iodine,

 

You claimed that we have no way of detecting heat, which we now have established is to mean temperatures above 45oC.

 

 

Actually that is confusing heat and temperature which I have not done. You are totally misquoting me or putting words in my mouth.

 

I have said things like,

I gave an example before that is apt.. Run barefoot in the snow for 10 minutes and then go inside a warm house. It will feel like your feet are on fire. Cold + Warmth (<45 degrees) = Burning sensation.

 

 

Warmth in that case does not involve such high temperatures as you claim.

 

None of my claims have even involved pain or nocireceptors.

 

It has been my claim throughout this thread that cold sensations COUPLED with warm sensations can create Mild (not pain) burning sensation. I have also said that this is how the body detects something hot (not painfully hot).

 

If you can catch me saying something different anywhere in this thread please point it out. It would have been in error.

 

Honestly. This is in speculations now as I expected, but this is science whether recognized by people here or not. It seems like a science forum rejecting science.

 

Maybe we should contact various science centers and tell them to remove the Thunberg's thermal grill illusion from their floors because this 150+ year old experiment is deemed pseudoscience by Scienceforum.(seemingly as a collective)

Edited July 16, 2014 by barfbag

[iNow]

Are you saying (I want to be clear), "People cannot feel heat".

<...>

When you say "Changes in temperature" do you mean a TRANSFER OF ENERGY?

 

Want a youtube video of little vibrating molecules, because I'm sure there are many?

No.

[Strange]

If I understand you correctly, you are saying that experiencing warm and cold together causes the experience of burning heat?

 

From his you deduce that we have no direct way experiencing "heat" (something extremely hot rather than just warm)?

 

That conclusion does not necessarily follow. We could have a mechanism for experiencing dangerous heat (or cold) which is stimulated by this grill illusion. And, in fact, that appear to be what one of your sources says:

 

There are three types of receptors:

 

• warm thermoreceptors are activated by the warm coils,
• cool thermoreceptors are activated by the cool coils and
• nociceptors, which create the stinging sensation of pain.

 

And:

 

Your skin is embedded with thermoreceptors that respond to either warm or cool temperatures as well as pain or nocioceptors that respond once the temperature goes past certain thresholds (thought to be above 45°C and below 10°C). If you touch a really hot surface (say about 70°C), your pain receptors, rather than your warm thermoreceptors, are activated.

 

From: http://www.questacon.edu.au/outreach/travelling-exhibitions/perception-deception/exhibits/can-temperature-cause-surprising-sensations

 

So it seems we do have receptors that respond to "heat" and they can be fooled into responding to "warm".

[iNow]

^Ergo, this:

 

The heat sensation comes when something is so hot it can stimulate both the warm and cold receptors at the same time.

... is demonstrably false, and consequently this:

 

I only mentioned it casually in a three sentence post (which is 100% correct).

... shows how you should, in fact, be asking of yourself this question instead of any of us:

 

Does anybody ever admit being wrong around here ?

... because as has been repeatedly shown you were quite simply not "100% correct."

[barfbag]

@ Strange,

 

If I understand you correctly, you are saying that experiencing warm and cold together causes the experience of burning heat?

 

From his you deduce that we have no direct way experiencing "heat" (

 

 

Yes. If the warm and cold thermoreceptors overload and reach their capacity pain will follow as the nociceptors kick in. You have stated this correctly. There is no direct way for the skin to detect a burning sensation (below the level of pain) without activating the Cold Thermoreceptors. It is the two together that make us run when we are in hot sand.

 

If it was serious burning pain, all three receptors are activated.

 

There are three types of receptors:

Quote

 

• warm thermoreceptors are activated by the warm coils,
• cool thermoreceptors are activated by the cool coils and
• nociceptors, which create the stinging sensation of pain.

 

 

 

 

Yes. If you read this thread I have mentioned each of these three receptors pretty much constantly so this is not new information.

 

Example from post 13,

 

there are a number of thermo receptors that respond to different temperature ranges - Hypervalent_Iodine

 

(from post 4)

 

So how many are we talking about? I say three. Cold Thermoreceptor, Warm Thermoreceptor, and nocireceptors which are used in sensory overload to indicate pain ONLY.

 

 

 

From the following quote though you pasted,

Your skin is embedded with thermoreceptors that respond to either warm or cool temperatures as well as pain

 

 

Note your quote says responds to warm, cool, or pain. This thread is about how we experience temperatures above warm. Holding a coffee in a paper cup for example requires the activation of warm and cold to feel the intense heat (Energy conducted from cup to hand).

 

This thread is not about the nocireceptors because this thread is not about feeling pain, it is about feeling intense heat, but it is true that if the object is extremely hot like a stove element it will quickly overload both warm and cool thermoreceptors and the nocireceptors will also kick in inducing pain.

 

your pain receptors, rather than your warm thermoreceptors

 

 

 

I have problems where this article says "rather than". Because all three receptors are activated in the event of extreme temperatures, but again this thread is about how we experience the "Hot" sensation as opposed to warm or cool, so discussing pain and nocireceptors are pretty much off topic.

 

So it seems we do have receptors that respond to "heat" and they can be fooled into responding to "warm". - Strange

 

 

Correct again. although I'd say they could be fooled into thinking something is hot merely by activating the warm and cool (added cool) thermoreceptors.

 

 

Thanks for your input. Finally someone understands this.

 

Too bad Scienceforums thinks it is pseudoscience though, because every science center in the world likely has the Thunberg's thermal grill illusion running 5 days a week, which this is merely an explanation of.

[Strange]

There is no direct way for the skin to detect a burning sensation (below the level of pain) without activating the Cold Thermoreceptors. It is the two together that make us run when we are in hot sand.

 

I see nothing in the sources you cite to support that point of view.

[barfbag]

@ Strange,

 

I see nothing in the sources you cite to support that point of view.

 

 

 

No worries then. You have company in your view apparently.

 

Maybe next time you're at a science center you can try it for yourself, or run cold water on your hand till tit is almost numb and then put it in lukewarm water to feel the burning.

 

It may be a kids experiment (Variant of experiment in kid video in post 6), but even an adult can learn this way.

 

If you lived in a Northern climate you would already know that if you come in from a snowball fight and your hands seem frozen they will experience a burning sensation while they acclimate. Are their hands really burning, or is it because both warm and cold thermoreceptors are activated.

 

Anyways... I am finished with this thread, people are posting more insults than citing their position.. Cheers.

 

I am somewhat curious as to how others think a hot sensation is felt. Does all the scientific papers on Thermoreceptors mention a hot thermoreceptor that I've never heard of? I mean they say pretty clearly that they detect warm and cold and pain. How can anyone think warm means hot?

 

A nocireceptor registers pain, not the sensation of hot.

Edited July 16, 2014 by barfbag

[Strange]

Maybe next time you're at a science center you can try it for yourself, or run cold water on your hand till tit is almost numb and then put it in lukewarm water to feel the burning.

 

I have no doubt about this effect at all. I have heard of it before (and experienced the burning effect - without even needing particularly cold or warm conditions because of Raynaud's disease).

 

But there appears to be no logical connection between this and your claim that "There is no direct way for the skin to detect a burning sensation (below the level of pain) without activating the Cold Thermoreceptors". So I was assuming there was some independent source that would confirm this.

[CharonY]

It is mostly due to the rather liberal use of definition that resulted in the erroneous conclusions drawn in OP. There is a reason why precise language in science is quite important.

 

For example this summary:

 

Yes. If the warm and cold thermoreceptors overload and reach their capacity pain will follow as the nociceptors kick in. You have stated this correctly. There is no direct way for the skin to detect a burning sensation (below the level of pain) without activating the Cold Thermoreceptors. It is the two together that make us run when we are in hot sand.

 

Is a nice narrative, but either slightly wrong, if we keep things on the analogy level, or very wrong if we want to be slightly precise how the receptors actually work. The receptors are not coupled in any way, so there is no overload of one and another kicking in. Rather, you have a wide range of ion channels that are temperature sensitive. Their opening results in action potentials that are then subsequently (to keep it simple) interpreted as temperature sensation. These belong to the TRP family of ion channels and various members react to different temperatures. E.g. TRPV4 is activated at moderate temperatures (up to roughly low 30s) whereas TRPV2 reacts if a temperature of more than 50 is reached. While the mechanisms are, to my knowledge, not fully elucidated, it allows sensory neurons to react distinctly to a quite broad range of temperatures.

 

Note that this is in reference to the "detect" part of the OP; i.e.

 

The nerves can detect cold and they can detect warm, but not heat.

 

The tricky part, however, is that in addition to thermosensors (i.e. neurons with these channels) nociceptors exist and react to a broad range stimuli (polymodal C-nociceptors are activated by heat, cold and pinching, for example). However, it is not that one system is overloaded and thus activating the others but there are parallel processing of this information as well as interactions of various levels.

 

This forms the basis of the Thurnberg illusion, which, just to make clear, is physiologically distinct from how we typically sense harmful temperature. One important and somewhat confusing element is the grill activates thermoceptors, but not nociceptors. What actually happens is the following. The activity of polymodal C-nociceptors (that invoke the pain) are typically masked by the activity of thermoceptors that react to cooling. On the grill however, their activity is inhibited by the application of warmth. Thus the information from the thermosensors no longer blocks the activity of the the nociceptors letting the brain interpret the resulting signal as pain. Note that physiologically this is closer to what happens when the body actually experiences noxious cold (not heat).

 

Thus the grill evokes a patterns that confuses the circuits by interfering with proper cold-sensing. To put it crudely it fuddles with the normal thermosensory circuits in such a way that the pain receptors suddenly tell the brain what is going on (wrongly) rather than using the proper pathways. Obviously, actual exposure to harmful temperatures would activate the nociceptors instead of the thermosensory circuits (i.e. not an overload, but parallel processing).

 

In other words, OP is misinterpretating the illusion with the way how typical heat sensing is processed, which is alright, as it is actually quite complicated. However, the further extrapolation based on this misinterpretation is what pushed this to the pseudoscience area.

[barfbag]

@ Charony,

 

I said that was my last post, but you deserve a response after such a good post. It has been the best response (imho)

 

This forms the basis of the Thurnberg illusion, which, just to make clear, is physiologically distinct from how we typically sense harmful temperature.

 

 

I do want to be clear that this thread is not at all about "harmful temperatures", only the sensation of feeling something hot. Unless someone is proposing nocireceptors are what detects a hot sensation (below pain), they should not even be a part of this thread.

 

However, it is not that one system is overloaded and thus activating the others but there are parallel processing

 

 

I know they are not connected and I think there are a lot fewer warm thermoreceptors than cold ones (or vice versa). What I meant is that a dangerous heat would activate warm/cold thermoreceptors as well as nocireceptors. I've said this before.

 

Interconnection to Other Receptors

• Thermoreceptors do not work by themselves.The are interconnected with other receptors. For example, when heat or cold become too great, thermoreceptors stop firing. The signal is taken over by pain receptors, called nocireceptors, which fire and transmit pain signals.Read more : http://www.ehow.com/info_8347530_receptors-detect-cold-heat.html

 

 

This is a better description of what I meant. (become too great = overload)

 

@ Chalcony. ...

 

One question only. What occurs to the cold receptor if you are holding a hot cup of coffee? Is it active or dormant? ( I mean this figuratively, of course they are always active (usually neutral)).

 

Edit: Too late... I'll answer this myself...

 

Zotterman (1959) found that cold fibers respond strongly to both cold stimuli and at hot stimuli. (see below quote)

 

(Note. I will add bolds and underlines to the following quote for emphasis.....)

 

Experiencing Sensation and Perception

Page 12.

9

Chapter 12: Skin Senses

reduction of warms to another part of the skin. It took a bit of time, but at the edge of the warm area, an extra warm band developed and next to the cooler area an even cooler area was experienced.

The Perception of Hot The discussion to this point of thermal responses of the body has been in terms of cold and warm, not cold and hot. In the stimulation of discussion of stimulating the skin with fine thermal stimuli, cold and warm spots were discovered (Dallenbach, 1927). But most of us have acute experiences of hot. Still, all of the physiology to still finds two types of sensory fibers responding to temperature and they seem to correspond to cold and warm, well mostly. Zotterman (1959) found that cold fibers respond strongly to both cold stimuli and at hot stimuli. Warm fibers respond most around body temperature but still seem torespond to the higher temperatures. This leads to a hypothesis about how the experience of hot might be generated. Perhaps, hot is experienced when both the cold and warm receptors fire at the same time. Asimple apparatus, called the heat grill, supports this contention about how a hot experience happens, Figure12.x. In the heat grill a cold stimulus is placed right next to a warm stimulus. Neither stimulus along generate the perception of heat or hot

[ Barfbag note: Also note how this University feels comfortable saying Heat and Hot ].

In fact, the cold stimulus alone generates a cold experience and the warm stimulus feels pleasantly warm. However, together the person feels heat and many will jerk their armaway as if it were being burnt. Others report a stinging burning sensation but can still keep the arm on theheat grill.

 

From this free PDF

http://psych.hanover.edu/classes/sensation/chapters/Chapter%2012.pdf

Is that citation clear enough to understand?

Now is that not exactly what I've been saying throughout this thread? Seriously! Is it not exactly my claim that has been delegated to the pseudoscience trash and ridiculed here..

(Will they move this to biology now?) (lol)

Here again is the three sentences that started this thread...

Fun Fact: The body has no nerves designed to feel heat. The nerves can detect cold and they can detect warm, but not heat.

 

The heat sensation comes when something is so hot it can stimulate both the warm and cold receptors at the same time.

 

 

oh... yes... 100% accurate... Even the terminology "heat" is used as casually by the University who created that PDF.

I think apologies are due (by some), not you Chalcony (you at least made effort to counter, TY).

Thank you. Thank you. Thank you very much. (bows).

THE END

Edited July 16, 2014 by barfbag

[CharonY]

 

What I meant is that a dangerous heat would activate warm/cold thermoreceptors as well as nocireceptors

 

No, it would not. Above a certain temperature the thermosensors do not react. That is what makes the illusion weird. I.e. it actually activates thermosensors that do not elicit the stinging pain, whereas during actual pain only the nociceptors are active, whereas the thermosensors are not. This is quite distinct from overloading. I.e. if the temperature is very high, the actual thermoreceptors are not firing at all.

 

With regard to hot coffee and cold receptors, your answer/speculation is quite wrong again. The actual response is highly dependent on the type of thermosensory cell (or rather, its decoration with heat or cold sensitive channels). Some integrate information from high and low temps and change firing frequency accordingly. So typically fibers associated with cold sensing will fire continuously at body temp, increase firing rate at cold temps and, in case of hot coffee, will reduce their firing rate.

 

What you mention is a speculation that was formed quite a while back, but is not substantiated by current knowledge anymore. See for example Craig and Bushnell, Science 1994 265/5169 p.252.

 

Also note that you should have started off with the citation (dated as may be) rather than with own speculations to streamline the discussion. The reason for the presence of the pseudoscience is less the content, but rather the way information is presented. I.e. you were presenting speculations as facts and only now added a pdf that at least somewhat supported that claim. Of course, the pdf itself is not actual primary literature and only presented speculation by itself, which, as I pointed out, is simply not in line with current (well, about as current as I can remember last time reading about it, which is easily a decade year old) knowledge.