Page 71 - BBC Focus - August 2017

UNDERSTAND

PAIN

Everybody hurts, but why? We explore the science of pain

WORDS: PROF IRENE TRACEY

We may have learnt to tame it with CIP, in which a person doesn’t get the of things, which is why pain is often
drugs, but pain is one of the warning ‘hurt’ of pain after severely called a ‘multidimensional’
certainties of human existence. It can damaging themselves. Historically, experience.
b be both physical and emotional, they didn’t survive to adulthood due So, what do you do? Well, from past
ranging from a searing torment to a to the consequences of unfelt injury. experiences, learnt responses, and
mild soreness. But what exactly is it, potential outcomes (like being told off
what function does it serve, and how What does pain do? for dropping the pan) you make a
can we really know how much pain Pain motivates us to act. Think about decision and act. Recruiting
someone is in? that hot pan again. Now imagine extraordinary brain-based networks,
you’d picked up the pan before you are able to block the pain and get
What is pain? realising it was too hot to handle. the hot pan to safety – then it’s back to
Simple, you’d think. You touch a hot Your options are to drop it and make a that cold tap. Pain drives action,
saucepan by mistake and it hurts like mess, or bear the pain until a solution prompting us to run away, avoid it in
hell. You immediately withdraw your is found. In an instant, you detect that the first place, or signal to others that
hand, rush to the tap and run cold the pan is hot (thermal), it’s on your we need help and relief.
water over it. Phew. No need to rush hand (location), it’s painful
to A&E. But then it throbs for days, (intensity), you don’t like it How do we feel pain?
reminding you of the burn and your (unpleasant), it’s engaged your full J Just underneath our skin surface, we
carelessness until the pain fades attention (cognition), and you’re not have an intricate network of ‘pain
away. Lesson learned: you’ll be more hap at s a ot ne ith special
appy about t (e ot o a ).py about it (emotional). That’s a lot
ner e fibres that endrve fibres’ that end with special 2
careful ar nd cookers in f re.
This simple incident can tell us a
lot about pain. Mostly, it’s a brilliant
warning system. Without it, you
would not have withdrawn your
hand, and the injury would be much
worse. Pain like this – what we call
‘acute pain’ – is a good thing: it’s key
to our survival. That’s why the ability
to experience pain is shared across
species. A few people include plants
in this, too, but as plants have no
nervous system or brain, it’s hard to
know how they’d actually feel pain
when injured or cut. Pain is
evolutionarily old, an essential
warning that something in the
environment can cause us injury,
harm, or even death.
Without pain, you’re in trouble. We
know this, sadly, because there’s a
PHOTOS: GETTY X2 rare genetic condition, which we call Emotions can amplify pain: people who are nervous at the dentist may have a harder time than more relaxed patients
o
co ge tangenital insensitivity to pain’ or
‘co
ty to pa
se s t
71