The second paradox of pain is something I've always found very interesting, that there is no one thing in the brain, no one circuit or center, where pain happens. The only convergence, based on what I've read, is in our categorization of the particular experience as "pain". That's caused some (Daniel Dennett, Jennifer Corn, etc) to take an eliminative attitude toward it. But pain seems undoubtedly useful as a concept in everyday talk, so I think the right approach is to figure out the mapping between the everyday concept and all the disparate underlying phenomena.
But it's also a stark reminder that a psychological concept, in many cases, won't cleanly map to a neurological one. A psychological kind isn't necessarily a natural kind, or maybe more precisely, isn't just one kind, but could be numerous different kinds.
Isn't that also true of vision and smell (and, I presume, hearing & taste)? Don't all of our sense send signals variously to the thalamus and the insula as well as the sense-specific parts?
It's definitely true that sense processing is far more complex than we might naively think. Seeing a tree, for instance, involves a lot more than just the visual cortex, but depends heavily on the temporal lobe (at least based on what I've read). But we seem to intuitively think pain should be simpler, more primal, involve far less evaluation than it does. And different types of pain seem to be as different from each other as smell and vision are from the other senses.
Pain does feel like a useful concept. I wonder whether its a levels problem. We want to talk about pain at a higher level, because we can share experiences at this higher level. But we want a lower level explanation. The problem is that a lower level explanation might not map neatly onto our higher level concepts.
I think something like that is it. The concept of chairs doesn't exist at a particle physics level, and there's no one precise topology that maps to "chair", yet the chair concept remains useful to us at the level of our interactions. And to your point, the pain category seems like a vital concept at the social interaction level.
I got very frustrated in my class on philosophy of mind because the tutors always wanted to use pain as an example of why the mind is separate from the brain but they barely had an understanding of how pain works themselves. I know a little bit more now!
I hope you are able to say more about the insula at some point (I have a tumour in mine). My understanding is that it pulls together all the senses to create a big picture view of what is going on around me and some role in emotions that I don't quite understand. Is that close?
I'm so sorry to hear you have a tumor in your insula. I hope it doesn't cause too much trouble.
The insula is involved in so much! It's a 'hub' that integrates information from various areas. So, the list of things it is involved in would be long.
In terms of senses, it seems to play a role in combining inputs from different senses. It's also crucial for interoception - our ability to sense internal bodily states. This is why it's so important for pain processing.
And in terms of emotion, the insula seems to play a role in experiencing emotion. There's a difference between experiencing an emotion and knowing you are experiencing an emotion. The insula is involved in the former. This is probably true because it has direct access to information about bodily states, and bodily states are necessary for experiencing emotion. This ties back to its role in interoception - our insula helps us 'feel' our emotions in a very literal sense.
Yes interesting article. Just as couple of things from my own particular perspective. One is that while neuroscience does not yet know what pain or any other element of consciousness ultimately exist as, to me this should merely be a current failure. I suspect that neuroscientists will determine that pain, vision, and all consciousness, ultimately exist in the form of an appropriate electromagnetic field associated with the right sort of synchronous neuron firing.
Then secondly, it seems to me that modern psychology is in much worse shape today than neuroscience. Much of the psychological components to what we feel, ought to be more understandable once psychologists are able to effectively model our nature. Consider the possibility that we’re all instantaneous selves that seek to feel as good as we can from moment to moment, though we’re connected with the past through our memory of the past, and we’re connected to our perceived future though the hope and worry that we currently feel about that future. Enduring pain should be chosen when it brings us enough hope, and this is because hope feels good to us presently. Enduring pain should also be chosen when it diminishes the general worry that we have about a given situation. Some day our softest forms of science ought to be able to help us understand ourselves far better than they do today.
You mention that enduring pain should be chosen when it brings enough hope or diminishes worry. How do you think this relates to chronic pain?
Does seeking to feel as good as we can from moment to moment also include sometimes sacrificing feeling good in the moment so we can feel good in the future?
Do you think that this hope in the future might explain the placebo effect?
If chronic pain makes a person feel like there’s nothing they can do to diminish it, then that should not be hopeful to them (or shouldn’t offer such potential to feel good), and also should be worrying to them (or should directly feel bad). But often I think people figure out how to get by with chronic pain in a “new normal”. There might be a diminishing marginal disutility (just like standard diminishing marginal utility).
I think was reading someone here recently (probably Ragged Clown) about how assisted suicide is slowly becoming acceptable in certain countries. I’m all for that!
When someone decides that they’re going to endure something horrible, like chemotherapy for example, my psychological theory is that this is because the instant hope of that suffering will overcome the perceived horrors of what they think they will end up enduring. (And they can certainly be wrong!) This gets into, not your mentioned “painfulnes pathway”, or “suffering pathway”, but rather the top down “pain suppression pathway”. And in truth I’d include “amplification” in that title because while you were focusing on hopeful things that someone can think about regarding their future, there can also be worrying things that feel negative.
Imagine being in a foreign land where you don’t speak the language, but you perceive being liked and respected by the people you meet. These interactions ought to be hopeful to you. But let’s say you’re actually quite disrespected and hated there. Perhaps you’re in mortal danger with a reasonable chance of being beaten and killed. As you get clued in to your actual situation, your hope should quickly change to worry. Note that the only thing which will change here is your top down thought rather than any body sensed pain. But this ought to feel horrible. Here consciousness itself (electromagnetic?) feeds back to the brain to change new consciousness into something that feels this way.
On placebo, yes hope might help explain it even medically, that is should positive feelings help someone in some medical sense.
As always, wonderful work, and thank you so much. I have questions! First, is the only difference between the nociceptors the myeline? so that in robotics if you wanted to mimic the human body you'd have to create faster and slower pathways or responses, or, I'd guess, robots only feel fast pain? Secondly, do you think masochism, for example, is purely cognitive? or might it have something to do with a mix-up in the anterior cingulate cortex? And finally, I've heard that an early experience of pain in children can cause them to be more sensitive to pain later, which I think doctors think is related to the new development of pain pathways for some reason. Or can the pain gates somehow get stuck open?
No, the only difference between nociceptors is not just the myelin. Different types of nociceptors have different thresholds. Most nociceptors are high-threshold, meaning they only respond to potentially damaging stimuli. However, some are low-threshold responding to relatively mild stimuli. In some conditions, like inflammation or nerve injury, nociceptors can become sensitised. This lowers their activation threshold, making them respond to stimuli that wouldn't normally be painful.
Different types of nociceptors also respond to different kinds of stimuli. Some react to heat, others to chemical irritants, and others to mechanical pressure (like when you kick your toe).
In terms of robotics, I suspect, mimicking human pain would involve more than mimicking nociceptors. Pain is complex, it goes far beyond merely detecting potential and actual damage. That being said, we don't yet have a complete understanding of the neuroscience of pain.
To get human-like pain, I'd suspect that we'd at least need to replicate: sensory detection (like nociceptors), signal transmission (including different speeds for different types of pain), emotion (bodily awareness), cognitive components (the suffering aspect of pain), modulation systems (like how we can sometimes ignore pain), and perhaps integration (integrating the signal with other information).
On masochism... I take 'purely cognitive' to mean processes, beliefs, and learned associations, and ACC mixup to mean atypical functioning. Given this, I suspect that atypical functioning can't be the only cause of masochistic behaviour because pain perception is significantly influenced by context for masochists. Masochists experience reduced pain perception in an erotic context but their pain perception in other situations remains normal. That being said, masochistic activities (like all activities) changes the brain. Research shows that, the longer someone has been interested in masochistic activities, the more pronounced these neural changes become.
On early pain experiences in children... There does seem to be evidence that early experiences of pain, especially in infancy and early childhood, can lead to increased pain sensitivity later in life. During early development, the nervous system is highly plastic. Pain experiences during this critical period can influence how pain circuits develop and function at various levels -- from changes in nociceptor sensitivity to alterations in how the brain interprets pain signals. That said, while early pain experiences can increase the risk of later pain sensitivity, this isn't inevitable. The developing nervous system is also remarkably resilient.
Thank you so much. You’re such a fountain of information and insight. It is such a pleasure to encounter someone who loves the work so much that she sees it from so many different angles.
I almost hate to do this to you, but I think you have such valuable insight on this conversation, both as a human person and as an expert in neuroscience. Here’s the link: https://substack.com/home/post/p-146316376 and here are the questions. First, there’s a bunch of people apparently believing in the “computational theory of mind.” such that “the mind can be understood as a system that processes information like a computer” (etc.) My opinion is that’s hare-brained, if you’ll pardon the expression, but the question I really wanted you to address is whether we ought to consider all the people involved in an enterprise they happily believe will involve Billions of human deaths in the interests of spreading cognitive function throughout the universe so devoid of humanity that they should be stopped at all costs, including imprisonment. If you don’t feel like taking on quite such an extravagant question (though I mean it very seriously), perhaps you could take a position on whether their antics are dangerous to the future of humanity?
Thanks for the link, Jack, and your trust in my thoughts!
You're right. These questions are extravagant! I don't normally get involved in political questions except to say that complex questions like these are best answered with much science and many honest conversations. I haven't read the article yet (it's been a busy week for me), but I guess that if their argument relies on the computational theory of mind, we might want to question the legitimacy of this theory, especially if the consequences of accepting such claims could lead to extreme conclusions.
My hope is that my work here in this little newsletter adds to this conversation. I think we should question our underlying theories and start a conversation about the far-reaching implications of our ideas.
Haha, very politic! We’ll see how you feel after reading the article, though. These people are lunatics, and the article points to a troubling aspect of science in general, namely that while individual scientists may have ethical limits, the field as a whole does not - they will take actions that doom us all (see, e.g., nuclear weapons and biological weapons, and now AI). Thanks for your response. I thought I might be asking too much this time, and you are always very kind.
A really good simplification which again makes me wish that I had, through some wormhole in space-time, been able to attend your lectures. Nonetheless, this more than suffices (and lets me get some naps in - not during, to be clear!). Thank you.
Pain presumably predates our becoming self-aware so pain and our responses to it often go under our conscious mind - like the reflex when you touch something hot. But if there's nobody there to feel pain then what is pain? I wonder if there are actually two different things: the pre-consciousness pain that drives the avoidance reflex, and the post-consciousness pain that's been bolted on top to enable us to plan to avoid pain.
Fascinating! Pain does seem like more than one thing, doesn't it!? Pain might even be more than two things -- it could be a whole orchestra of different processes.
If we want to say that pain predates self-awareness then, we need to talk about what we mean by pain. Can we call it pain if there's no self-aware entity to experience it? After all, if there's nobody there to feel the pain, is it really pain?
Reflexes are interesting -- they seem quite primitive and likely don't require awareness. For example, I imagine that when plants like the Venus flytrap snap shut, this automatic response might not mean the flytrap is conscious. Our reflexive jerk away from a hot stove might be a bit like this. So should we not call reflexes pain? Perhaps.
Can the experience of pain exist without a someone? And what exactly is this "someone" who experiences pain?
Presumably the avoidance reflex is triggered by pain receptors, so in that sense it's pain; often the reflex goes via the spinal cord rather than the brain, the pain getting to the brain as an afterthought.
Presumably all this existed before our ancestors developed consciousness cos even protozoa avoid unpleasant stimuli.
The mind-body problem is an ongoing project in philosophy (as I'm sure you know). The evolutionary development of consciousness is hard to envisage cos it only seems to be useful when you've connected it all together. This rather suggests that pain was fully functional before there was anybody there to experience it. Personally I suspect awareness appeared in adult amphibians (ie during metamorphosis from tadpole) which maps to human embryos, but this is only a guess. Maybe fish have it too; the research is conflicted. (Fish are hugely diverse group anyway so you can't generalise)
The curious thing is if we take a bunch of nociceptors and put them in a petri dish and stimulate them, would we call the response pain? I'm not sure we would. What is a reflex without a brain? Is it like a neuron in a petri dish? To get the experience of pain, do we need the brain too?
The other curious thing is that nociceptors don't differ that much from other types of receptors that are not associated with pain. So, why are some neurons associated with pain and some are not? These are the sorts of questions that fascinate me!
And is the difference structural and there from the start or does the brain learn which is which?
(Thinking as I go here) I think it must be structural:
A. cos the first time you get toothache it's in your tooth.
B. cos all this was evolved in our segmented ancestors when tactics were handled at segment level and the head just did strategy :). The (partial) transfer of function to the brain came later, tho I guess this wiring could still be learned. (the segmental ganglion is left semi-autonomous with the brain having final override - but not before a delay imposed by the comms)
The way we can localise all the different receptors (e.g. we know which fingertip senses heat, cold, pain or touch) suggests we have one or more body maps like the retinal map(s) we use for vision (I think I've seen diagrams of this).
We distinguish the signals from our 3 (usually) types of eye colour receptors (cones) (and the rods) even though they presumably travel up identical nerves. The other different senses are probably kept distinct the same way (whatever that is). Occasionally it fails and we get synesthesia.
Having now worked out what I expect it's time to do some reading and find the ugly fact that destroys the beautiful theory!
That's science for you -- always with its 'ugly facts' out to destroy 'beautiful theories'. Though in this case, I think you're not too far off with the structural differences. We know there are distinct pathways for different types of sensory information, even if there's still debate about exactly how these develop.
This is a topic I've always found super interesting. I've noticed that I can often talk myself out of being bothered by pain by pretending it's a good sensation - when I've got an annoying headache but also when I gave birth. What I don't understand is that your body seems to be able to react differently to exactly the same stimulus - my friend gave birth to two children and found one birth agonising and one fine, and can't see any medical reason for it!
Your example of how you can reframe pain is a great example of how our thinking can influence our experience of pain. If only this worked every time! If pain management was just a matter of thinking, none of us would be that bothered by pain.
But there are so many different factors that influence our experience of pain. Stress, anxiety, and our past experiences can amplify or dampen pain perception. Hormones are also a big one -- especially during childbirth. Context and expectations also play a huge role -- anticipation and the situation surrounding the pain can significantly impact our experience of pain. And of cause there's neuroplasticity -- our brain is constantly changing. Past pain experiences can alter how we experience pain in the future.
Informative essay on a very important topic Suzi! 👏 Hope you'll do a companion piece on effective (evidence-based) approaches to pain management. Regarding the cognitive/interpretive aspect of "pain", I learned in a hypnotherapy course about self-suggestion techniques such as envisioning pain as heat or cold. Quite a dramatic decrease in the "suffering" quotient! Most medical professionals under-address pain so more science/info on that is for the good.
Thanks Baird, for your thoughtful feedback and suggestion! While medical research is a bit outside my wheelhouse, your idea about exploring evidence-based approaches to treatments is something I'm very interested in. Your point about hypnotherapy and self-suggestion techniques is fascinating -- I'll add it to the article idea list!
Yes, I did skip over the amygdala. You're right, I should have said something about it here.
Every time I write an article I create two files. One, is the draft I'm working on and the other is the 'dump file' for that article. The dump file is where all the thoughts that don't make the final cut get pasted. This week's dump file is long! And much of it contains information about the amygdala.
Traditionally, the amygdala is known primarily for its role in emotion processing, especially fear responses. So, it wasn't considered a primary pain processing centre. But recently there's been much more work looking at its role in pain perception, especially in relation to chronic pain. Some of the latest research suggest that the amygdala is heavily involved in the pain suppression pathway.
I'll say much more about the amygdala when we get to emotions.
On the pain-pleasure pathway, perhaps because we have become more open to discussing topics that were once considered taboo, like pain and pleasure during sex, we've seen an increase in research on these sorts of topics. We're still learning, but the main findings seem to be that context really matters for our perception of pain.
An excellent overview Suzi!
The second paradox of pain is something I've always found very interesting, that there is no one thing in the brain, no one circuit or center, where pain happens. The only convergence, based on what I've read, is in our categorization of the particular experience as "pain". That's caused some (Daniel Dennett, Jennifer Corn, etc) to take an eliminative attitude toward it. But pain seems undoubtedly useful as a concept in everyday talk, so I think the right approach is to figure out the mapping between the everyday concept and all the disparate underlying phenomena.
But it's also a stark reminder that a psychological concept, in many cases, won't cleanly map to a neurological one. A psychological kind isn't necessarily a natural kind, or maybe more precisely, isn't just one kind, but could be numerous different kinds.
Isn't that also true of vision and smell (and, I presume, hearing & taste)? Don't all of our sense send signals variously to the thalamus and the insula as well as the sense-specific parts?
It's definitely true that sense processing is far more complex than we might naively think. Seeing a tree, for instance, involves a lot more than just the visual cortex, but depends heavily on the temporal lobe (at least based on what I've read). But we seem to intuitively think pain should be simpler, more primal, involve far less evaluation than it does. And different types of pain seem to be as different from each other as smell and vision are from the other senses.
Got it! Thanks for following up.
Pain does feel like a useful concept. I wonder whether its a levels problem. We want to talk about pain at a higher level, because we can share experiences at this higher level. But we want a lower level explanation. The problem is that a lower level explanation might not map neatly onto our higher level concepts.
I think something like that is it. The concept of chairs doesn't exist at a particle physics level, and there's no one precise topology that maps to "chair", yet the chair concept remains useful to us at the level of our interactions. And to your point, the pain category seems like a vital concept at the social interaction level.
I met a child who was unable to feel pain, it was heartbreaking.
That is heartbreaking. I'm so sorry to hear that.
It really was. His mom explained it to me and how often he got hurt because he couldn't feel pain.
Fantastic, Suzi. Thank you.
I got very frustrated in my class on philosophy of mind because the tutors always wanted to use pain as an example of why the mind is separate from the brain but they barely had an understanding of how pain works themselves. I know a little bit more now!
I hope you are able to say more about the insula at some point (I have a tumour in mine). My understanding is that it pulls together all the senses to create a big picture view of what is going on around me and some role in emotions that I don't quite understand. Is that close?
Thanks Ragged Clown!
I'm so sorry to hear you have a tumor in your insula. I hope it doesn't cause too much trouble.
The insula is involved in so much! It's a 'hub' that integrates information from various areas. So, the list of things it is involved in would be long.
In terms of senses, it seems to play a role in combining inputs from different senses. It's also crucial for interoception - our ability to sense internal bodily states. This is why it's so important for pain processing.
And in terms of emotion, the insula seems to play a role in experiencing emotion. There's a difference between experiencing an emotion and knowing you are experiencing an emotion. The insula is involved in the former. This is probably true because it has direct access to information about bodily states, and bodily states are necessary for experiencing emotion. This ties back to its role in interoception - our insula helps us 'feel' our emotions in a very literal sense.
Thank you, Suzi. I had an idea that the insula was involved in emotions. I know a little more now. Thank you!
Yes interesting article. Just as couple of things from my own particular perspective. One is that while neuroscience does not yet know what pain or any other element of consciousness ultimately exist as, to me this should merely be a current failure. I suspect that neuroscientists will determine that pain, vision, and all consciousness, ultimately exist in the form of an appropriate electromagnetic field associated with the right sort of synchronous neuron firing.
Then secondly, it seems to me that modern psychology is in much worse shape today than neuroscience. Much of the psychological components to what we feel, ought to be more understandable once psychologists are able to effectively model our nature. Consider the possibility that we’re all instantaneous selves that seek to feel as good as we can from moment to moment, though we’re connected with the past through our memory of the past, and we’re connected to our perceived future though the hope and worry that we currently feel about that future. Enduring pain should be chosen when it brings us enough hope, and this is because hope feels good to us presently. Enduring pain should also be chosen when it diminishes the general worry that we have about a given situation. Some day our softest forms of science ought to be able to help us understand ourselves far better than they do today.
Interesting ideas! I have questions!
You mention that enduring pain should be chosen when it brings enough hope or diminishes worry. How do you think this relates to chronic pain?
Does seeking to feel as good as we can from moment to moment also include sometimes sacrificing feeling good in the moment so we can feel good in the future?
Do you think that this hope in the future might explain the placebo effect?
If chronic pain makes a person feel like there’s nothing they can do to diminish it, then that should not be hopeful to them (or shouldn’t offer such potential to feel good), and also should be worrying to them (or should directly feel bad). But often I think people figure out how to get by with chronic pain in a “new normal”. There might be a diminishing marginal disutility (just like standard diminishing marginal utility).
I think was reading someone here recently (probably Ragged Clown) about how assisted suicide is slowly becoming acceptable in certain countries. I’m all for that!
When someone decides that they’re going to endure something horrible, like chemotherapy for example, my psychological theory is that this is because the instant hope of that suffering will overcome the perceived horrors of what they think they will end up enduring. (And they can certainly be wrong!) This gets into, not your mentioned “painfulnes pathway”, or “suffering pathway”, but rather the top down “pain suppression pathway”. And in truth I’d include “amplification” in that title because while you were focusing on hopeful things that someone can think about regarding their future, there can also be worrying things that feel negative.
Imagine being in a foreign land where you don’t speak the language, but you perceive being liked and respected by the people you meet. These interactions ought to be hopeful to you. But let’s say you’re actually quite disrespected and hated there. Perhaps you’re in mortal danger with a reasonable chance of being beaten and killed. As you get clued in to your actual situation, your hope should quickly change to worry. Note that the only thing which will change here is your top down thought rather than any body sensed pain. But this ought to feel horrible. Here consciousness itself (electromagnetic?) feeds back to the brain to change new consciousness into something that feels this way.
On placebo, yes hope might help explain it even medically, that is should positive feelings help someone in some medical sense.
As always, wonderful work, and thank you so much. I have questions! First, is the only difference between the nociceptors the myeline? so that in robotics if you wanted to mimic the human body you'd have to create faster and slower pathways or responses, or, I'd guess, robots only feel fast pain? Secondly, do you think masochism, for example, is purely cognitive? or might it have something to do with a mix-up in the anterior cingulate cortex? And finally, I've heard that an early experience of pain in children can cause them to be more sensitive to pain later, which I think doctors think is related to the new development of pain pathways for some reason. Or can the pain gates somehow get stuck open?
Thanks Jack!
No, the only difference between nociceptors is not just the myelin. Different types of nociceptors have different thresholds. Most nociceptors are high-threshold, meaning they only respond to potentially damaging stimuli. However, some are low-threshold responding to relatively mild stimuli. In some conditions, like inflammation or nerve injury, nociceptors can become sensitised. This lowers their activation threshold, making them respond to stimuli that wouldn't normally be painful.
Different types of nociceptors also respond to different kinds of stimuli. Some react to heat, others to chemical irritants, and others to mechanical pressure (like when you kick your toe).
In terms of robotics, I suspect, mimicking human pain would involve more than mimicking nociceptors. Pain is complex, it goes far beyond merely detecting potential and actual damage. That being said, we don't yet have a complete understanding of the neuroscience of pain.
To get human-like pain, I'd suspect that we'd at least need to replicate: sensory detection (like nociceptors), signal transmission (including different speeds for different types of pain), emotion (bodily awareness), cognitive components (the suffering aspect of pain), modulation systems (like how we can sometimes ignore pain), and perhaps integration (integrating the signal with other information).
On masochism... I take 'purely cognitive' to mean processes, beliefs, and learned associations, and ACC mixup to mean atypical functioning. Given this, I suspect that atypical functioning can't be the only cause of masochistic behaviour because pain perception is significantly influenced by context for masochists. Masochists experience reduced pain perception in an erotic context but their pain perception in other situations remains normal. That being said, masochistic activities (like all activities) changes the brain. Research shows that, the longer someone has been interested in masochistic activities, the more pronounced these neural changes become.
On early pain experiences in children... There does seem to be evidence that early experiences of pain, especially in infancy and early childhood, can lead to increased pain sensitivity later in life. During early development, the nervous system is highly plastic. Pain experiences during this critical period can influence how pain circuits develop and function at various levels -- from changes in nociceptor sensitivity to alterations in how the brain interprets pain signals. That said, while early pain experiences can increase the risk of later pain sensitivity, this isn't inevitable. The developing nervous system is also remarkably resilient.
Thank you so much. You’re such a fountain of information and insight. It is such a pleasure to encounter someone who loves the work so much that she sees it from so many different angles.
Thanks so much, Jack!
I almost hate to do this to you, but I think you have such valuable insight on this conversation, both as a human person and as an expert in neuroscience. Here’s the link: https://substack.com/home/post/p-146316376 and here are the questions. First, there’s a bunch of people apparently believing in the “computational theory of mind.” such that “the mind can be understood as a system that processes information like a computer” (etc.) My opinion is that’s hare-brained, if you’ll pardon the expression, but the question I really wanted you to address is whether we ought to consider all the people involved in an enterprise they happily believe will involve Billions of human deaths in the interests of spreading cognitive function throughout the universe so devoid of humanity that they should be stopped at all costs, including imprisonment. If you don’t feel like taking on quite such an extravagant question (though I mean it very seriously), perhaps you could take a position on whether their antics are dangerous to the future of humanity?
Thanks for the link, Jack, and your trust in my thoughts!
You're right. These questions are extravagant! I don't normally get involved in political questions except to say that complex questions like these are best answered with much science and many honest conversations. I haven't read the article yet (it's been a busy week for me), but I guess that if their argument relies on the computational theory of mind, we might want to question the legitimacy of this theory, especially if the consequences of accepting such claims could lead to extreme conclusions.
My hope is that my work here in this little newsletter adds to this conversation. I think we should question our underlying theories and start a conversation about the far-reaching implications of our ideas.
Haha, very politic! We’ll see how you feel after reading the article, though. These people are lunatics, and the article points to a troubling aspect of science in general, namely that while individual scientists may have ethical limits, the field as a whole does not - they will take actions that doom us all (see, e.g., nuclear weapons and biological weapons, and now AI). Thanks for your response. I thought I might be asking too much this time, and you are always very kind.
A really good simplification which again makes me wish that I had, through some wormhole in space-time, been able to attend your lectures. Nonetheless, this more than suffices (and lets me get some naps in - not during, to be clear!). Thank you.
Pain presumably predates our becoming self-aware so pain and our responses to it often go under our conscious mind - like the reflex when you touch something hot. But if there's nobody there to feel pain then what is pain? I wonder if there are actually two different things: the pre-consciousness pain that drives the avoidance reflex, and the post-consciousness pain that's been bolted on top to enable us to plan to avoid pain.
Fascinating! Pain does seem like more than one thing, doesn't it!? Pain might even be more than two things -- it could be a whole orchestra of different processes.
If we want to say that pain predates self-awareness then, we need to talk about what we mean by pain. Can we call it pain if there's no self-aware entity to experience it? After all, if there's nobody there to feel the pain, is it really pain?
Reflexes are interesting -- they seem quite primitive and likely don't require awareness. For example, I imagine that when plants like the Venus flytrap snap shut, this automatic response might not mean the flytrap is conscious. Our reflexive jerk away from a hot stove might be a bit like this. So should we not call reflexes pain? Perhaps.
Can the experience of pain exist without a someone? And what exactly is this "someone" who experiences pain?
Presumably the avoidance reflex is triggered by pain receptors, so in that sense it's pain; often the reflex goes via the spinal cord rather than the brain, the pain getting to the brain as an afterthought.
Presumably all this existed before our ancestors developed consciousness cos even protozoa avoid unpleasant stimuli.
The mind-body problem is an ongoing project in philosophy (as I'm sure you know). The evolutionary development of consciousness is hard to envisage cos it only seems to be useful when you've connected it all together. This rather suggests that pain was fully functional before there was anybody there to experience it. Personally I suspect awareness appeared in adult amphibians (ie during metamorphosis from tadpole) which maps to human embryos, but this is only a guess. Maybe fish have it too; the research is conflicted. (Fish are hugely diverse group anyway so you can't generalise)
The curious thing is if we take a bunch of nociceptors and put them in a petri dish and stimulate them, would we call the response pain? I'm not sure we would. What is a reflex without a brain? Is it like a neuron in a petri dish? To get the experience of pain, do we need the brain too?
The other curious thing is that nociceptors don't differ that much from other types of receptors that are not associated with pain. So, why are some neurons associated with pain and some are not? These are the sorts of questions that fascinate me!
And is the difference structural and there from the start or does the brain learn which is which?
(Thinking as I go here) I think it must be structural:
A. cos the first time you get toothache it's in your tooth.
B. cos all this was evolved in our segmented ancestors when tactics were handled at segment level and the head just did strategy :). The (partial) transfer of function to the brain came later, tho I guess this wiring could still be learned. (the segmental ganglion is left semi-autonomous with the brain having final override - but not before a delay imposed by the comms)
The way we can localise all the different receptors (e.g. we know which fingertip senses heat, cold, pain or touch) suggests we have one or more body maps like the retinal map(s) we use for vision (I think I've seen diagrams of this).
We distinguish the signals from our 3 (usually) types of eye colour receptors (cones) (and the rods) even though they presumably travel up identical nerves. The other different senses are probably kept distinct the same way (whatever that is). Occasionally it fails and we get synesthesia.
Having now worked out what I expect it's time to do some reading and find the ugly fact that destroys the beautiful theory!
Ah, the old nature-nurture debate!
That's science for you -- always with its 'ugly facts' out to destroy 'beautiful theories'. Though in this case, I think you're not too far off with the structural differences. We know there are distinct pathways for different types of sensory information, even if there's still debate about exactly how these develop.
This is a topic I've always found super interesting. I've noticed that I can often talk myself out of being bothered by pain by pretending it's a good sensation - when I've got an annoying headache but also when I gave birth. What I don't understand is that your body seems to be able to react differently to exactly the same stimulus - my friend gave birth to two children and found one birth agonising and one fine, and can't see any medical reason for it!
Hi Susannah!
Pain is fascinating, but also very complex.
Your example of how you can reframe pain is a great example of how our thinking can influence our experience of pain. If only this worked every time! If pain management was just a matter of thinking, none of us would be that bothered by pain.
But there are so many different factors that influence our experience of pain. Stress, anxiety, and our past experiences can amplify or dampen pain perception. Hormones are also a big one -- especially during childbirth. Context and expectations also play a huge role -- anticipation and the situation surrounding the pain can significantly impact our experience of pain. And of cause there's neuroplasticity -- our brain is constantly changing. Past pain experiences can alter how we experience pain in the future.
Informative essay on a very important topic Suzi! 👏 Hope you'll do a companion piece on effective (evidence-based) approaches to pain management. Regarding the cognitive/interpretive aspect of "pain", I learned in a hypnotherapy course about self-suggestion techniques such as envisioning pain as heat or cold. Quite a dramatic decrease in the "suffering" quotient! Most medical professionals under-address pain so more science/info on that is for the good.
Thanks Baird, for your thoughtful feedback and suggestion! While medical research is a bit outside my wheelhouse, your idea about exploring evidence-based approaches to treatments is something I'm very interested in. Your point about hypnotherapy and self-suggestion techniques is fascinating -- I'll add it to the article idea list!
Pain initially seems simple - it hurts or it doesn't. But that first impression is wrong. So many nuances.
I don't think you mentioned the role of amygdala or are you saving that for next time?
In addition to the three, pathways do we need a fourth - the pain pleasure pathway?
Hi James!
Yes, I did skip over the amygdala. You're right, I should have said something about it here.
Every time I write an article I create two files. One, is the draft I'm working on and the other is the 'dump file' for that article. The dump file is where all the thoughts that don't make the final cut get pasted. This week's dump file is long! And much of it contains information about the amygdala.
Traditionally, the amygdala is known primarily for its role in emotion processing, especially fear responses. So, it wasn't considered a primary pain processing centre. But recently there's been much more work looking at its role in pain perception, especially in relation to chronic pain. Some of the latest research suggest that the amygdala is heavily involved in the pain suppression pathway.
I'll say much more about the amygdala when we get to emotions.
On the pain-pleasure pathway, perhaps because we have become more open to discussing topics that were once considered taboo, like pain and pleasure during sex, we've seen an increase in research on these sorts of topics. We're still learning, but the main findings seem to be that context really matters for our perception of pain.
An excellent neuroscientific exposition of pain. I am looking forward to your take on fantom pain.