The Weird and Wonderful World of Pain Science

The science of pain is weird, but wonderful.

Pain is one of our key protective mechanisms, yet can end up causing us a world of suffering. Pain in and of itself is not a bad thing. It is our body’s way of warning us of danger, letting us know that there is something wrong. When it is a simple danger-reaction situation, pain is fairly straightforward. When this pain continues, chronically, even in the absence of damage to our physical body… well then we have entered the strange world of chronic or persistent pain.

What is Pain?

Let’s start with a basic overview of what pain is, and what it is not. Pain is not a direct feeling sent by the nerves of the body. If we stub our toe we do not feel pain coming directly from the toe. I know, this is a strange concept and it took me a little while to get my head around it too… Pain is actually a multisensory experience created by a number of different areas of our brain working together. It is a feeling, an experience, that manifests once the brain has decided we are in danger. Pain is created by the brain and influenced by biological, psychological and environmental factors.

Acute Pain

Pain is a very useful protective mechanism for the body. Nociceptive nerve fibres sense tissue damage and send danger signals to the brain. The brain uses the other sensory inputs - what it can see, hear, smell, feel - along with knowledge and memory to decide if those danger signals should be listened to. In the case of a stubbed toe, or our skin touching something very hot, the pain sensation is almost immediate and tells us our physical body is in danger. The pain will continue while the damage remains, but should decrease over time as healing occurs.

Chronic Pain

Unfortunately, sometimes pain can stay around after the tissue has healed. In fact, the longer pain happens the better our brains get at producing pain. Our nerves become sensitised too - overly responsive to any input and ready to send danger signals right away. Our conscious mind is primed to make pain, the pathways are well trodden.

If you’ve heard the phrase ‘neurons that fire together, wire together’, this is often the case with chronic pain. It means that once something happens that has triggered pain before, pain will result even if the subsequent damage doesn’t. For example, if bending over awkwardly injured your back once, then it makes sense that your brain might create pain when you next bend over, in anticipation of the damage that it assumes will occur…

This means there can be an extreme level of pain without any tissue damage at all, if the brain feels that the body is in danger. It also means that despite great physical trauma and tissue damage, if the brain doesn’t sense danger then it might not create pain. I told you this stuff was weird… Pain doesn’t always mean that there is tissue damage, or that the body is in danger.


“Pain doesn’t always mean that there is tissue damage, or that the body is in danger.”


Take phantom limb pain for example. The arm or leg is no longer there, yet the brain can create the experience of pain as if that limb were still attached, and in danger! Or, closer to home for those with Chronic Migraine, consider allodynia. This is a condition where even light touch on the skin feels horrifically painful. There isn’t any tissue damage, but the pain persists. Conversely, there have been studies involving people with MRIs showing significant damage to their spine, yet they feel no pain. Their brain isn’t aware of any danger from this damage and so it hasn’t created pain.

Pain response factors

So, what contributes to the experience of pain? It has been suggested that it comes down to a combination of the following, and this is not an exhaustive list:

  • Nociceptors (nerve fibres)
  • Sensitisation (peripheral and central)
  • Fear
  • Depression & anxiety
  • Memories of pain
  • Attitude towards pain
  • Beliefs
  • Age
  • Gender
  • Emotional & psychological state in the moment
  • Societal & cultural factors

As you can see, this is a much longer list than simply - nerves sensing pain. My mind was blown open when I learnt this last year!

The empowering thing about this list is that some of these can be influenced by us. While we can’t control the nociceptors or our level of sensitisation (although we might be able to change this over time) we absolutely can work on our attitude towards pain, beliefs about pain, fear of the pain, and we can address anxiety & depression.

How does this relate to Migraine?

People with Migraine don’t fit neatly into the same chronic pain classification as those with chronic musculoskeletal pain. There usually hasn’t been one serious moment of tissue damage that then transformed into persistent pain over time. Instead, each attack is another assault on our system, another release of inflammatory mediators and vascular changes in the brain. There is no denying this.

However, this is not to say we cannot influence our experiences! We absolutely can. Staying physically and mentally healthy is really important, as we know more frequent and severe Migraine is associated with poor health. We can work on our attitude towards and beliefs about this disease. We can start to face our fears about Migraine, both the fear of pain and the fear of living life with this condition. It could be useful to bring extra support onto your team - a psychologist, massage therapist, yoga teacher, physical therapist or exercise physiologist.

I have found over the past year that some attacks start when I begin to worry about the fact that I might be heading into an attack… I can’t pinpoint any other triggers, and perhaps it would have occurred anyway, but I know deep down that the pain is worse when I’m nervously anticipating it. When I fear the pain, the pain escalates. This isn’t fair, but for me it is reality.

Meditation has been an excellent way to calm my whole system down and bring myself into the present moment. Daily practice has become a mainstay of my self care. There is some research suggesting that meditation can help us manage Migraine too!

We can also get some exercise! You knew that suggestion was coming right? Exercise brings us back into our bodies, lowers stress, helps lift depression and brings healthy benefits to all of our systems. It can also give us back the power of knowing that we can influence how we feel. Exercise helps us learn to feel safe and strong in our bodies again, we can move without pain, we can move and not cause pain, we can enjoy movement despite Migraine.

Sensitisation

I think it’s worth mentioning sensitisation as a separate point. Peripheral sensitisation is caused by long term potentiation, which means the nerves responsible for triggering the danger signals are activated again and again and again. So in Migraine, the trigeminal and occipital nerves in particular are very very good at sparking the Migraine response. This could potentially be partly due to peripheral sensitisation. Peripheral sensitisation also involves a hypersensitive state during the Migraine attack itself, which is why bending over, coughing, moving too much all cause a marked increase in pain.

Central sensitisation takes this one step further and simply put means our whole nervous system becomes hyperexcitable and overly responsive to inputs. We might experience a decreased pain threshold overall, so that even the lightest touch can hurt. We might also have an exaggerated pain response to a normally painful stimulus. So, our brain creates more pain than is necessary for the situation. I don’t know about you, but I feel like my brain does this often for Migraine attacks, and the pain of these attacks has been increasing gradually over time. It’s almost as if my brain was getting better and better at creating Migraine pain, and started to do so more efficiently and viciously with each attack.

We can directly shift the physiology at play here with medication, such as the new CGRP medications, Botox or other preventatives. However we can also indirectly disrupt the cycle by chipping away at the fear component, the anxiety, the expectation that this attack will be worse. Personally, I have found that learning about how pain is created has actually already changed my pain response. I know the pain will pass, I understand that it doesn’t mean my brain is in actual danger and I can remind myself that I just need to relax until it is over. The attacks of the past few months (give or take a few awful menstrual moments) have been less intense. The meditation, exercise, Botox, journaling, supplements and understanding about pain have all helped here I’m sure.

Safety vs danger

According to the Explain Pain model (a wonderful approach outlined in this book), one way we can successfully lower our pain experience is by shifting the balance of safety beliefs and danger beliefs. If pain is created when the brain thinks we are in danger, and the pain is more severe if the danger is sensed to be greater, then by lowering the perceived threat we might be able to lower the pain.

One way to do this is to focus on all the things that are good, safe and positive in any given situation. So, when a Migraine attack is beginning, we can remind ourselves all the reasons that we are SAFE and not actually in danger. For me these phrases have become part of my attack toolbox:

“I am safe, I am OK”
“My head is in pain now but it will pass” & “I have survived this before”
“I can get through this” & “I can handle this”
“I have everything I need to get through this right here”
“My home is so comfortable and reassuring”
“I am loved, and I am worthy”
“I am strong and resilient”
“This is not how it will be forever”


What to do with this information

This post has become an essay! I hope all the information here isn’t too overwhelming. I find it empowering to think that there ARE things we can do that will have an impact on our pain. After experimenting with these ideas myself over the past six months I would say these are the four key things I try to focus on now:

  • Lowering my anxiety levels overall
  • Managing my fear
  • Keeping myself healthy
  • Recognising the good things, the safety messages I can send my brain

If you would like to read more about pain the following sites are particularly great, and there are references down below for the really nerdy amongst us! If you have any questions for me, head over to Instagram and ask me there.

References

Burstein, R., Jakubowski, M., & Rauch, S. D. (2011). The science of migraine. Journal of Vestibular Research, 21(6), 305-314.

Louw, A., Diener, I., Butler, D. S., & Puentedura, E. J. (2011). The effect of neuroscience education on pain, disability, anxiety, and stress in chronic musculoskeletal pain. Archives of physical medicine and rehabilitation, 92(12), 2041-2056.

Moseley, G. L. (2003). A pain neuromatrix approach to patients with chronic pain. Manual therapy, 8(3), 130-140.

Moseley, G. L. (2007). Reconceptualising pain according to modern pain science. Physical therapy reviews, 12(3), 169-178.

Disclaimer: I am not a Doctor, or a headache specialist or an expert in this area. I studied this at an undergraduate level as part of my Exercise Physiology degree, and the information here is a blend of what I learnt plus further research on my own time.

  • Post by Emily Cordes
  • Feb 28, 2020