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misgfool
To my (limited) understanding, the peripheral nervous system sends messages of pain in the form of electrical impulses to the brains. But what's the difference between signals of extreme pain and mild pain/touch?
Monique said:Well, what is the difference between looking at a dim light and an ultra-bright light. The latter will make you squint your eyes: it is a matter of the amount of stimulation. You have different receptors for different types of information: the nocireceptor senses injury and is thus responsible for feeling pain, you also have mechano- and thermoreceptors.
Monique said:The introduction of this review is interesting (about the difference between non-painful and painful sensory stimuli): http://linkinghub.elsevier.com/retrieve/pii/S0959-4388(97)80028-1" .
First, there is a threshold that needs to be crossed before the nocireceptor starts to fire a signal. When there is sufficient stimulus, an action potential is created: the membrane of the neuron depolarizes (the voltage increases), the voltage peaks after which you get a hyperpolarization and a refractory period. The action potential spreads to the adjacent membrane, so that it can travel along the axon. The refractory period ensures that the signal can only travel in one direction, once the membrane has recovered it can fire again. The neuron can either be slightly excited giving a sparse signal, or strongly excited giving a continuous signal. I hope that addresses your question.misgfool said:I'm interested in the actual signal that travels, like it's waveform, amplitude, phase etc? So that brains know that this is serious pain, output a mighty roar from mouth.
Wikipedia is free:misgfool said:I'm interested in the actual signal that travels, like it's waveform, amplitude, phase etc? So that brains know that this is serious pain, output a mighty roar from mouth.
I was looking for a bit (100%) cheaper article.
The conduction of nerve impulses is an example of an all-or-none response. In other words, if a neuron responds at all, then it must respond completely. The greater the intensity of stimulation does not produce a stronger signal but can produce more impulses per second. There are different types of receptor response to stimulus, slowly adapting or tonic receptors respond to steady stimulus and produce a steady rate of firing. These tonic receptors most often respond to increased intensity of stimulus by increasing their firing frequency, usually as a power function of stimulus plotted against impulses per second. This can be likened to an intrinsic property of light where to get greater intensity of a specific frequency (color) there has to be more photons, as the photons can't become "stronger" for a specific frequency.
Pain
An unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage. Note: The inability to communicate verbally does not negate the possibility that an individual is experiencing pain and is in need of appropriate pain-relieving treatment. Pain is always subjective. Each individual learns the application of the word through experiences related to injury in early life. Biologists recognize that those stimuli which cause pain are liable to damage tissue. Accordingly, pain is that experience we associate with actual or potential tissue damage. It is unquestionably a sensation in a part or parts of the body, but it is also always unpleasant and therefore also an emotional experience. Experiences which resemble pain but are not unpleasant, e.g., pricking, should not be called pain. Unpleasant abnormal experiences (dysesthesias) may also be pain but are not necessarily so because, subjectively, they may not have the usual sensory qualities of pain.
Many people report pain in the absence of tissue damage or any likely pathophysiological cause; usually this happens for psychological reasons. There is usually no way to distinguish their experience from that due to tissue damage if we take the subjective report. If they regard their experience as pain and if they report it in the same ways as pain caused by tissue damage, it should be accepted as pain. This definition avoids tying pain to the stimulus. Activity induced in the nociceptor and nociceptive pathways by a noxious stimulus is not pain, which is always a psychological state, even though we may well appreciate that pain most often has a proximate physical cause.
Many people report pain in the absence of tissue damage or any likely pathophysiological cause; usually this happens for psychological reasons.
# Symptoms associated with seizures from the postcentral gyrus include tingling, numbness, pain, heat, cold, agnosia, phantom sensations, or sensations of movement.
# Abdominal pain usually originates from the temporal lobe, and genital pain from the mesial parietal sensory cortex.
There is usually no way to distinguish their experience from that due to tissue damage if we take the subjective report. If they regard their experience as pain and if they report it in the same ways as pain caused by tissue damage, it should be accepted as pain. This definition avoids tying pain to the stimulus. Activity induced in the nociceptor and nociceptive pathways by a noxious stimulus is not pain, which is always a psychological state, even though we may well appreciate that pain most often has a proximate physical cause.
Monique said:First, there is a threshold that needs to be crossed before the nocireceptor starts to fire a signal. When there is sufficient stimulus, an action potential is created: the membrane of the neuron depolarizes (the voltage increases), the voltage peaks after which you get a hyperpolarization and a refractory period. The action potential spreads to the adjacent membrane, so that it can travel along the axon. The refractory period ensures that the signal can only travel in one direction, once the membrane has recovered it can fire again. The neuron can either be slightly excited giving a sparse signal, or strongly excited giving a continuous signal. I hope that addresses your question.
Axons don't work the same way as a conductor in an electric circuit. How much do you know about conventional electric circuits? It's hard to explain the difference without knowing how much you already know about either.misgfool said:Ok, so the voltage (amplitude) of the signal is higher for extreme pain than for slight pain. Now the second question is that, why is it so hard to reconnect nerves when they have been cut? If they only acts as conductors for electricity, why isn't it possible to reconnect them with any conducting material?
zoobyshoe said:Axons don't work the same way as a conductor in an electric circuit. How much do you know about conventional electric circuits? It's hard to explain the difference without knowing how much you already know about either.
No, it is the number of pulses that are generated by the neuron.misgfool said:Ok, so the voltage (amplitude) of the signal is higher for extreme pain than for slight pain.
I can attest to this. Years ago, I suffered a mild stroke due to some prescription medication that sent my heart into atrial fibrillation. A small clot made its way to my brain-stem and the damage caused me to lose temperature sensation in my right leg AND to cause a constant severe burning sensation in my right foot. My neurologist said that even if my right leg was amputated due to some severe injury or disease, I would still experience this pain for the rest of my life. Neuropathic pain is not fun at all - it can't be lessened with pain-killers, etc.somasimple said:Nociception isn't pain. Nociception is the message that is sent to brain.
Pain is created only by brain.
turbo-1 said:I can attest to this. Years ago, I suffered a mild stroke due to some prescription medication that sent my heart into atrial fibrillation. A small clot made its way to my brain-stem and the damage caused me to lose temperature sensation in my right leg AND to cause a constant severe burning sensation in my right foot. My neurologist said that even if my right leg was amputated due to some severe injury or disease, I would still experience this pain for the rest of my life. Neuropathic pain is not fun at all - it can't be lessened with pain-killers, etc.
somasimple said:Nerves use ions that have electric consequences but a microchip is purely electric, far from the functioning of a nerve that have many ways to change its behavior.
And pain is not an incoming stimulus but a brain response to noxious (or considered as) stimulus.
The point is that you can't simply splice any old conductor into an axon.misgfool said:If nerves have electric consequences, they can be integrated with electric circuits.
zoobyshoe said:The point is that you can't simply splice any old conductor into an axon.
zoobyshoe said:I'm assuming you understand ions and cations. The electrical activity of nerves and neurons is based on actual physical motion of these, especially cations, rather than the EMF of conventional electricity based on electrons.
Wikipedia said:It involves measurements of voltage change or electric current on a wide variety of scales from single ion channel proteins to whole organs like the heart.
If I said a Stirling engine is not the conventional heat engine powered by exploding gases, would you object saying "There's only one (known) kind of heat in the universe. It's either a heat engine or it is something totally different. There is no conventional and unconventional heat."misgfool said:There is only one (known) kind of electricity in the universe. It involves the presence and flow of electric charge. There is no conventional and unconventional electricity. It's either electricity or it is something totally different.
zoobyshoe said:If I said a Stirling engine is not the conventional heat engine powered by exploding gases, would you object saying "There's only one (known) kind of heat in the universe. It's either a heat engine or it is something totally different. There is no conventional and unconventional heat."
I've heard of conditions where a physician will cut a nerve that is causing a noxious stimulus, but this is not an easy thing to do. What exactly is your idea about the application of the concept?misgfool said:There has to be some kind of sensory input coming to brains. All one has to do is to identify which signal is noxious and filter it out.
It's sounding more like you want to be a pain in the peripheral nervous system rather than alleviating it.misgfool said:I can't see the analogy. Also that example is incomprehensible and silly. No need to be offended. I was just stating a fact. Let's try to stick in the topic.
Monique said:I've heard of conditions where a physician will cut a nerve that is causing a noxious stimulus, but this is not an easy thing to do. What exactly is your idea about the application of the concept?
zoobyshoe said:It's sounding more like you want to be a pain in the peripheral nervous system rather than alleviating it.
How do you dial back pain safely? If your hardware solution makes extreme pain tolerable, how is the implantee going to be able to distinguish between pain that indicates that a mild amount of tissue damage may be occurring, and a (damped) sensation that on examination reveals that some really extreme damage is occurring? Doctors already have tools at their disposal (including narcotics) to deal with chronic pain, though as I posted above, their tools to deal with neuropathic-induced pain are limited and sufferers pretty much have to learn to live with it.misgfool said:All the more reason for you to focus in developing this chip, so that you can program it to filter the pain I'm causing.
And they stopped because they can't cut the brain.Monique said:I've heard of conditions where a physician will cut a nerve that is causing a noxious stimulus, but this is not an easy thing to do. What exactly is your idea about the application of the concept?
See Ramachanfran and phantom limb pain.zoobyshoe said:Therefore: I don't agree with the characterization of pain as a "psychological" experience in all cases. It would, by this author's logic, be accurate to say that our experience of heat and cold are always "psychological" as well. At the same time it is accurate to observe there is no dedicated "pain" signal; that a neutral signal's conversion to a perception of pain takes place in the brain, that conversion is a neurological, and not a psychological, event. The same neurological event can be triggered by means other than the normal stimulus (eg: simple partial seizure, trigeminal neuralgia), without it becoming a psychological event. The word "psychological" conotes emotional interpretation in the context of personal history.
A ion that is moving creates an electric field that is effectively electricity but where is the circuit?misgfool said:There is only one (known) kind of electricity in the universe. It involves the presence and flow of electric charge. There is no conventional and unconventional electricity. It's either electricity or it is something totally different.
What's this problem you have with the brain? If a neuron is misfiring and thus causing trouble, you need to tame it. The brain adds another level of complexity and it certainly can cause problems, but that does not mean you can completely ignore the effect of the neuron itself.somasimple said:And they stopped because they can't cut the brain.
turbo-1 said:Pain is not pleasant, but it has real survival value.
somasimple said:A ion that is moving creates an electric field that is effectively electricity but where is the circuit?
Conventional electronic chips need electric circuits. A neuron has no dedicated wires or electric circuit. No circuit let's an useless electric field.
somasimple said:And a chip needs energy.
somasimple said:And a last and quite definite problem is that you can't cut an axon without killing it.
it doesn't mean anything, sorry.I wouldn't cut an axon, just separate two of them from each others.
somasimple said:it doesn't mean anything, sorry.
An axon is a single piece you can't separate from the soma.