explain
pain
section
2
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Themessage is processed throughout the brain
Lots of others are processed at the same time
S
o, if the dangermessenger nerve from the tissues gets
past the synapse, the dangermessage goes up the spinal
cord into the brain. The dangermessage arrives along with
a lot of othermessages and they are all processed by the
brain.
The challenge for the brain is to construct as
sensible a story as possible, based on all the
information that is arriving and the vast amount that
is already stored inside.
The brain ‘weighs the world’ and
responds by doingmany things, one of which is giving you
a perception of what is happening. One way to think of pain
is that it is part of the response of the brain to the
information that is arriving. (Other responses could be
moving, sweating, speaking etc.).
In the last ten years, technology has allowed scientists to
take pictures of what is happening in the brainwhen people
experience things such as pain.
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We have probably
learnt more about the biology of pain in the last twenty
years than in the previous thousand years.
One of themost important things that we have learnt is
that in a pain experience, hundreds of brain parts are
involved simultaneously. Although consistent patterns can
be seen during pain experiences, the exact parts and
amount of activity vary between people and even between
measuring occasions in the same person.
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Every pain
experience is unique.
There is not just one pain centre in the brain, as people
used to think. There aremany areas whichmay be
involved in pain. We call these areas ‘ignitionnodes’.
These brain parts include clusters of nodes used for
sensation, movement, emotions andmemory. Pain just uses
these parts to express itself. In chronic pain, some of these
nodes become very sensitive and it is as though they are
repeatedly hijacked intowhat we call a pain neurotag. (See
Ornithology and Amazing Grace in ‘Painful Yarns’
17
)
In the figure overleaf, we have identified some of the brain
parts that are often active (‘ignited’) during a pain
experience. These parts all link up to each other electrically
and chemically. It’s a bit like the picture you find in the back
of an airlinemagazine that shows all the routes across the
country. The particular pattern of activitywhich creates the
perception of pain can be considered a ‘neurotag’ for pain.
We acknowledge its origins fromMelzack’s neuromatrix.
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