Sunday, September 23, 2007

Pain For Dummies - Part I

or: what you always wanted to know about pain but were afraid to ask.

What's this pain thing all about then?

Well - acute pain has a lot of useful functions: it is a warning signal that draws our attention towards a damaged area (or to the potential of damage occurring in the future). It enables our brain to react even before we become aware of it. It protects us from doing more damage, and signals - by way of muscular action - other people that we have a problem in a specific part of our bodies (just think of the way you hold your arm when it hurts).

It also interferes with cognitive processes by altering Emotions and Mood - which is another way that other people can tell that there is something "wrong" with us. What good is pain if you can't communicate it to the world around you?

Some used to think that there is a pain center in the brain. But all the brain imaging studies done over the past 10 or more years show a different picture: pain processing centers are everywhere. Pain is a so-called multidimensional sensation - it's the unique combination of effects it has that makes it so powerful.
It invades every aspect of life - and vanishes just as quickly when the danger is gone.

The most dramatic way to show how important pain is in everyday life is in people who are born without the ability to feel pain (congenital insensitivity to pain); it is a very rare disorder - but with very dramatic effects. If one of their bones is broken they still use it as if it were alright - leading to more and more damage and life threatening infections.

The best definition so far is the one provided by the IASP:
"An unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage."

Notice the "described in terms of such damage" - that's my favorite part. Think about a visit to the dentists office; for a lot of people there doesn't have to be pain in order to feel it. The smell, the sounds, the faces of others in the waiting area and the (bad) memories one has about previous visits is enough to elicit a stress response - and lead to "imaginary" pain.

There are two important lessons here:
1) our brains are pattern seeking and prediction making machines
and
2) the link between stress and pain

1) our brains start looking for patterns the moment we are born. Babies will smile at anything that resembles a face - even a piece of cardboard with two eyes and a mouth. Our brains are hardwired to look for faces especially - that's why we are able to see them anywhere - in clouds, in trees, ...
That's why highkey portraits work so well - they reduce a (human) face to the most basic structures our brains seek - eyes, a mouth and a bit of skull outlined.

Windows To The Soul

So if you brought your brain with you to the dentist it starts analyzing the situation: the smell of antiseptic, the high-pitched sounds of the drill, the facemask (very uncool and unintentionally threatening) - and perhaps bad memories from past visits.

How can your brain not see a pattern that says: "Beware - Pain ahead!". It has to do this - it's hardwired to protect you.
The same goes for every other painful experience you ever had - if your brain recognizes a similar pattern it will make you uncomfortable in advance of the actual experience. It prepares you for action.

2) The "stress response". How does your brain prepare you for such a situation when you are - based on the brains prediction - likely to experience pain?:
by up-regulating your natural stress response - changing the heart rate, shutting down digestion, pumping adrenaline into the bloodstream, ... - all the reactions your body needs in order to flee and or to survive.

You have to remember that our brains developed over several hundred million years - so they still expect sabre-tooth tigers to jump at us from behind mailboxes - not dentists who want to help you. Our brains have learned that overreacting is better than the other way round and essential for survival.

So today any stressful situation leads to the full array of stress responses.
And this is the simple link between stress and pain. Stress makes you more likely to experience pain - and as such relaxation techniques are helpful - they remove part of the pain experience which can make pain easier to live with.
Actually short term stress reduces pain (think the "shock" after a traumatic event) - but long term stress heightens it.

In the next posting we will look at the multidimensional nature of pain.

2 comments:

OAndreas said...

I know this stress response very well as you know:-)

Here are some good examples for pattern recognition regarding faces:
http://morgenbauer.com/2007/04/05/menschen-sehen-immer-menschen/

dermoneuromodulator said...

Hi Matthias, so glad to read your thoughts in English. I've got you bookmarked now. Looking forward to your next post.