Taking the Suffering out of Pain

July 10, 2012

I wrote this essay as an entry to the Max Pertuz Science writing award competition run by the Medical Research Council… it was quite a tricky task, writing about my research in no more than 800 words and in a way that would appeal to the ‘lay-reader’, but I really enjoyed giving it a shot, even if I wasn’t successful! There’s always next year…

Anyway, here it is:

I’m going to introduce you to a new a way of thinking about pain: It’s not just pain, or at least it’s not just what most people think of as pain. To explain what I mean, think of the last time you stubbed your toe, and how you would describe it:

“I can feel the pain only in my toe but it really hurts! It’s sharp to start with, but it soon dampens and becomes more of a dull throbbing ache that gets sharper again if I knock it.”

A network of nerves crisscross our bodies, the front line when it comes to detecting pain. These tiny fibres tell us not only that we have been hurt, but also where, and what might have caused it. The density of nerves dictates how precise we can be in pinpointing the source of the pain – we need more in our skin because something that hurts us on the outside can potentially be avoided if we know where it is, whereas stomach ache isn’t exactly something you can run away from!

“I was pretty stressed out at the time as I was rushing to meet friends – sitting on the bus, I was really aware of my toe still being sore and it put me in a bad mood.”

I don’t need to tell you that feeling pain affects your mood (usually negatively), but the opposite is also true, emotions can change our experience of pain. This association between pain and emotion is more useful than first appearances would have you believe – at the most basic level, it’s a protective mechanism, allowing us to learn from pain, and change how we behave to avoid getting hurt again.

“As soon as I met my friends, I was so pleased to see them that I completely forgot about my toe – I noticed it a bit on the way home but it was nowhere near as bad as it had been.”

With the million-and-one things the brain deals with on a daily basis, we’d be lost if it couldn’t prioritise. Luckily for us, it’s pretty good at knowing when we should make a fuss, and when there are better things ways to spend energy on – in this case, fun definitely trumps moping over a sore toe! We can distract ourselves, tell ourselves it’ll be ok (even if it might not feel that way at the time), and use a whole range of techniques to stop non-threatening pain from intruding upon our everyday lives.

So I think we’ve established that pain isn’t as simple as “ow” – only looking at the sensory side of pain means you could be missing out on a huge chunk of the story. Understanding how pain and emotion interact – what parts of the brain are involved, and how emotional behaviour changes when pain outlives its usefulness is at the heart of my research.

Mis-functioning receptors and overactive nerve fibres might be the root causes, but looking at pain in a more complete way, trying to understand how it influences behaviour, is vital to understanding pain as a whole. We are complicated animals and knowing how the brain interprets these signals and what happens to us when protective behaviour goes too far is crucial to easing the burden of pain in modern society.

The key player in the emotional brain is an area in the temporal lobe called the amygdala – its ability to link events with emotions allows us to recognise potentially harmful situations based on our experiences, and thankfully, as with pain, the brain has the option to over-rule when it thinks we are over-reacting!

I’m exploring what happens in the amygdala when pain stops being useful and starts being unhelpful, as is often the case when pain transitions from short-term (acute) to more prolonged (chronic). Alongside this, my work aims to understand how this is reflected in behaviours caused by anxiety and fear, the two main emotions originating from the amygdala and strongly associated with pain.

By comparing two very different forms of pain (the internal pain of cystitis, and pain in the hands and feet caused by nerve damage), I hope to highlight what they have in common, and how they change our behaviour towards the world, whether through a fear of re-injury or a more general sense of losing enjoyment of life.

Trying to understand why some people develop chronic pain, whereas others don’t is one of the major challenges in pain research today – by studying the emotional side of pain I hope to add a piece to this ever-expanding puzzle so we can not only predict who is vulnerable, but provide protection. Pain will always be inevitable, but one day, suffering may become optional.

Written by Rosie Posted in Science Tagged with 2012, health, Max Perutz Award, medical research council, MRC, pain, science