Yoga Research: Study Explores the Brain’s Role in the Experience of Pain
For many decades, neuroscientists have wrestled with the notion that the brain itself might play a key role in the modulation of pain. Several researchers, most notably Melzack and Wall, have theorized on the various systems that are activated through the “gating” process that allows the brain to dampen pain from local injury or even to burn more hotly through various unconscious reflexes.
But the real burning question that has mystified the scientific establishment for so long is this: can the brain itself be the sole cause of pain in the absence of any nociceptive input from the spine?
Pain management researchers and manual therapists have suspected for some time that some portion of chronic back pain represents ongoing dysfunction in the brain and nervous system rather than any local spinal injury. To buttress their case, they point to the fact that it is difficult to identify and verify a specific, obvious local pain generator in most chronic neck and low back pain cases.
Study Suggests Brain Involvement in Pain
A recent study from the University of Pittsburgh suggests that the brain can indeed generate pain in the absence of any local nociceptive input. Stuart W. Derbyshire, Ph.D., and colleagues hypnotized eight experimental volunteers (1). They then studied patterns of brain activity:
While the subjects received a painful thermal stimulus
While they believed they were receiving a painful thermal stimulus but were not
While they were aware, they were not receiving painful stimuli.
The hypnotic state in which the subjects believed they were receiving a painful stimulus resulted in a similar pattern of symptoms and brain activation as pain from the real thermal insult. There was notable activity in the thalamus (the great sensory integrator) and prefrontal and parietal cortices.
“These findings compare well with the activation patterns during pain from nociceptive sources and provide the direct experimental evidence linking specific neural activity with the immediate generation of a pain experience,” according to Derbyshire and colleagues.
It’s Not “All in Your Head”
This cleverly designed study provides direct evidence of the brain generating pain in the absence of any actual noxious input. The significance of this study is profound for pain management therapists since many functional disorders are commonly seen in the clinical setting that appear idiopathic, such as fibromyalgia and some low back/neck pain cases. Now we know that these are real disorders and may actually have roots based upon the mechanisms described by Derbyshire.
It is helpful to remember that if you or your clients regard an experience as pain and if you or they report it in the same way as pain caused by tissue damage, it should be accepted as pain. This definition avoids tying pain to the stimulus.
Because brain scanners can’t be fooled, the new brain imaging technology is an extremely effective and objective way to explore reported experiences of pain. The fact that hypnosis was able to induce a painful experience in the absence of an actual external stimulus suggests there is a neural network for pain. In other words, some pain could really be in the brain.
Yoga and the Pain Response
Slow, mindful yoga practice can be a powerful tool in pain management. Gentle movements that encourage settling into the parasympathetic (rest-and-digest) side of the autonomic nervous system can be especially helpful.
Restorative Yoga is designed to elicit the relaxation response, but you can practice traditional poses such as forward bends and twists, with a “cooling” intention. For example, instead of practicing with the intention to get somewhere, focus on the internal experience unfolding at the moment. Breathe slowly, deeply, and without strain, allowing your body to settle into each asana in its own time.
Reprinted with permission from Erik Dalton.com
Erik Dalton, Ph.D., is executive director of the Freedom From Pain Institute, creator of Myoskeletal Alignment Techniques, and author of three best-selling manual therapy textbooks and online home-study programs. Educated in massage, osteopathy, and Rolfing, he resides in Oklahoma City, Oklahoma, and San Jose, Costa Rica. View his articles and videos at www.erikdalton.com or Facebook’s Erik Dalton Techniques Group.
1. Derbyshire S. et al, Neuroimage, 23 (1):392-401. https://www.ncbi.nlm.nih.gov/pubmed/15325387