Why does pain exist

Just for fun, have a look at the complex version of that diagram. This two-way functionality in the pain system is the main difference between modern pain science and old-school pain science. But most of the modulation is probably central: we only feel what our brains allow us to feel. The quality and intensity of the final experience is clearly the product of an elaborate set of neurological filters.

Perhaps many patients whom doctors treat as having a nerve injury or a disease have, instead, what might be called sensor syndromes. This is no less true for human beings. Our sensations of pain, itch, nausea, and fatigue are normally protective. Unmoored from physical reality, however, they can become a nightmare … hundreds of thousands of people in the United States alone suffer from conditions like chronic back pain, fibromyalgia, chronic pelvic pain, tinnitus, temporomandibular joint disorder, or repetitive strain injury, where, typically, no amount of imaging, nerve testing, or surgery manages to uncover an anatomical explanation.

Doctors have persisted in treating these conditions as nerve or tissue problems—engine failures, as it were. We get under the hood and remove this, replace that, snip some wires. Yet still the sensor keeps going off.

So we get frustrated. If pain isn't just a response to signals from the tissues, what is pain actually a response to? The previous section gave the modern version of how pain works in a very non-technical way. Pain is the output of a dazzlingly complex threat-detection system that generates pain experiences roughly in proportion to perceived threat, based on all kinds of sensory inputs as well as meaning and context.

All that input produces the neuromatrix , a distinctive, fingerprint-like pattern of neurological activation determined by genetics, experience especially trauma , and finally by our immediate situation.

If the model hurts, then you hurt. So the way pain really works is much more complicated, interesting, and in some ways useful than the naive view. So what do they detect, if not pain? Noxious stimuli. And what are those nerves? In fact, we are constantly exposed to lots of minor noxious stimuli without pain.

On the other hand, major sources of nociception — like from a burn, cut, or stepping on a Lego on your way to the bathroom at 2am — usually do lead to pain. But not always. And pain can sometimes happen without any nociception at all. Or it might just be out of proportion to it! The difference between pain and nociception is critical to understanding the weirdness of pain. But knowledge is good.

We cannot trust our eyes, and we cannot trust our pain. Pain is a lot like these amazing illusions — that is, it is warped by our expectations and point of view :. Japanese professor makes amazing 3D optical illusions But that challenge is what recovery is all about: trying to change our expectations and point of view with interesting new sensations and movements.

In some cases, they also show how it is influenced by our minds, directly or indirectly. For example, being in love influences pain, and being in love is richly psychological — but also infamously uncontrollable. Thanks to a quirky study, science has confirmed that being in love relieves pain — a wonderful example of the potential power of the mind over pain. As researcher Dr. But we can work to give love more of a chance to grow and thrive. Closely related: pain is also muted when romantic partners hold hands.

If you view a painful hand through a magnifying glass, it will actually get more swollen and inflamed — that is, if you make it look bigger, it will feel like a bigger problem. Use optics to make it look smaller, and swelling will go down.

Incredible, right? Jedi pain tricks! But … do you have a de -magnifying glass handy? Where do you buy even one of those, let alone a big one?

They really are hard to find. How about looking backwards through binoculars? Not a great solution. Two similar illusions, using virtual reality goggles to make it look like the knee was either shrinking or stretching. The pain system evolved to report problems, and you can count on it to do so most of the time.

This is a photo of three-legged cat Isaac, trying to scratch himself with his missing leg :. That has got to be super frustrating! Poor little guy!

His brain has a picture of how things should be, and he acts accordingly. Mind has some influence over brain.

No laser tracks. No remaining signs of recovery. It was ahead of schedule. But my right eye was a bit blurry, and it ached. In reality, it was also healing on schedule — but it was lagging behind the ahead-of-schedule left, and it was freaking me out a bit.

Get a load of what my science-minded optometrist said paraphrasing when I told him about this:. My optometrist described the following scenario paraphrasing :. They accidentally cover one eye while watching television, happen to notice that the vision in the free eye is a bit off. I was paying close attention to my vision in the aftermath of the surgery — probably too close. And so it started to ache.

Good grief. Sensation and pain are nothing if not mercurial. On the one hand, we can be driven half out of our minds by a bit of beef wedged between a couple teeth. Or, stuck right in the other hand, a large piece of metal can be painless for 50 years. Like a turn signal lever. Art Lampitt got one of those embedded in his arm in a car accident long ago.

What with all the other injuries, no one noticed. His arm began to ache and swell and an x-ray revealed a strange, thin third arm bone. I love medical marvels that challenge our preconceptions about what will hurt. This next example is extracted whole from Marni Jackon's superb book, Pain: The science and culture of why we hurt.

This is an amazing anecdote about the power of perception, and what I want to highlight here is that this wasn't just a case of medical fear and panic: it was a painful experience. He tells a story of one midnight emergency to illustrate his point.

Then she heard him calling her name, followed by the thud of him falling to the floor. She found him unconscious, white-faced, and covered in sweat. And in the toilet there was a quantity of bright red blood. Livingston told her not to flush the toilet and rushed over. He found the man lying on the bed, conscious, but in pain. Where does it hurt the worst, Livingston asked. He went on groaning as his wife said that he had been in fine spirits and good health, until he had gone to the bathroom.

Livingston examined him, to no avail. Then he went into the bathroom and inspected the alarming-looking contents of the toilet.

Lots of beet fragments. It turned out that her husband had eaten beets for lunch, and little else. The two of them walked back into the bedroom with smiles on their faces, which annoyed the husband, who was languishing on the bed.

It hurt all over. Because his brain absolutely believed he was in terrible danger. And no other reason. In the weird world of pain, fearing the worst is at least partially a self-fulfilling prophecy: the more worried you are, the worse things tend to do. Gary J Macfarlane, regarding a paper on knee replacement results :.

Although this evidence doesn't show it, it also seems reasonable to assume that the reverse is true: if worry is worse, probably hope helps. So anything at all that increases patient optimism and confidence is a good idea. But we cannot lie or conceal the truth, either!

There is no easy solution to this dilemma. This example of pain weirdness does not have the charming narrative appeal of some of the stories above, like being in agony from mistaking beet juice for blood.

In the beet juice example, we can see a strong element of behaviour in the pain, a a response response to a stimulus, a perceived threat. And behavioural responses to stimuli can be learned. Wiech, N. Weiskopf, R. Dolan and R. Slater, A. Antley, A. Davison, D. Swapp, C. Guger, C. Barker, N. Pistrang and M. Humans Show Empathy for Robots.

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Inherited cancer case studies Inherited cancer case studies. Complex genetic testing case studies Complex genetic testing case studies. Transcript Choose Transcript Language: English. My name is Dr. Ewan St. John Smith. I'm a reader in Nociception in the Department of Pharmacology in the University of Cambridge, and today we'll be talking about: why does pain exist?

How does it work? What can go wrong and how is it treated? So, the talk will be split into four parts. We'll look at, firstly, what pain really is and how it works. Obviously, there could be a lot of detail here to go into, but we're just going to give an overview of how the system is setup.

Then, we'll look at why does pain exists because some people think that a life without pain would be far simpler. Then, we'll look at what can go wrong with pain. We all know what pain feels like, but there are symptoms and syndromes that are particularly bad.

In the last part, we will look at how pain is treated. Again, there are lots of different treatments currently available, some being in trials, still. We're just going to cover some of the main treatments that are used. So, let's begin then by looking at: what is pain and how does it work? So, in terms of what is pain, internationally there are scientists, clinicians, nurses, physios, and so on that work on pain, and if we're going to have this word, we need to have an agreement about what is really meant by pain.

So, for this, the International Association for the Study of Pain, which are taxonomy committee, they have defined pain as follows: an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage. Most people think of just the unpleasant sensory nature of pain. If you pick up a hot cup of coffee that's too hot you go ouch, you put it down again.