Saturday, April 02, 2016

Pain does not equal nociception

Reading about pain can be very confusing. Why? Because those who are writing unconsciously or deliberately, from a biomedical standpoint, continue to conflate nociception and pain.
Once you learn the difference it is not so bad. Your brain will grow an automatic translation program that kicks in all by itself.

Here is the one I use:

1. Pain is a perception, perceived as a sensation.
2. The nervous system is separable, for mental exercise sake, into "central" and "peripheral"
3. Spinal cord is "central" nervous system, as is brain.
4. Once a signal reaches the first synapse in the dorsal horn, bam! it has reached the central nervous system.
5. Up to then, a noxious signal is merely nociception.
6. After that, if it makes it past that first hurdle, up to the thalamus and beyond, it may contribute to a pain experience.
7. Note that I said may contribute, which leaves space for a lot of other processing and inhibition before something else, called "pain," might be even potentially experienced.
8. Pain is multifactorial. Which means, experiencing it depends on a large number of factors.

It is good to know something about general features of sensory systems, the difference between tonic and phasic firing, and the difference between temporal and spatial summation, the difference between interoception (which, as far as I am concerned, includes proprioception) and exteroception. It's also good to know about the skin organ and where neurons came from. But none of those is what this blog post is about.

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