Friday, 13 May 2016

The Brain and Pain: Is Chronic Pain Changeable?

Brain and Pain
A while ago, I (Colleen) was having a discussion about pain with a friend who has fibromyalgia. One of her comments was that she believes it’s “all in her head.” (I cringed as she said that, but then listened to her reasoning.) She feels like there isn’t anything wrong with her tissue and body. It seems like her brain is hypersensitive to “pain signals,” just like it is to many other things (stress, sound, etc). I stopped cringing, and commented how cool it is that our brain’s perception of those signals can be changed.

Her reply was “Do you really think that can change?”

I responded: “Absolutely”

Why that answer? Back when we were in OT school we didn’t learn a lot about chronic pain other than, it was chronic. But since then, we’ve learned enough to convince us that it isn’t as static as we once thought. Yes, it is persistent, and yes, it is real. And no, there aren’t any magic wands to make it completely go away. But the research suggests that it is definitely possible to change our nervous system and our experience of pain.

So let’s take a peek at this idea. How did it become a part of the pain picture? And what is the evidence?

Some (Very) Basic Neurophysiology 

This idea of looking at the brain’s connection to pain is relatively new. A lot of it has come into play in the last few decades as new technologies have become available. We are now able to see what is going on in the brain during different activities (fMRI). Researchers and clinicians have begun to understand just how much the brain can, and does, play a role in pain. For the sake of this post, we are only touching on a few ideas. 

  • Neuroplasticity: One of the key points that has come out of this research is the idea of neuroplasticity - that is, our brains are changing every day and will continue to change for our entire lives (Butler, 2014).
  • Neurotags: Our brain is made up of tons of neurons that are interconnected in a complex way. A neurotag is a network of neurons from different areas of the brain. When this network is activated, it “generates a particular experience” (Cundiff & Schellinck, 2015; Moseley, Butler, Beames, & Giles, 2012). We have all kinds of neurotags, for a variety of different experiences, and the components that make up these neurotags are individual. For example, if you have experienced food poisoning after consuming a chicken burger, you could have a “food poisoning neurotag.” This neurotag would include neurons that are related to the smell of chicken, the appearance of a burger, the type of bun used, the restaurant you were at, etc. When enough of these neurons are activated, the whole neurotag gets activated, and you experience nausea (Cundiff & Schellinck, 2015)
  • Activation threshold: The activation threshold is the amount of input that is needed to cause a nerve cell to fire. Just like nerve cells have an activation threshold, neurotags need a certain amount of stimulation to be triggered. The activation threshold is the amount of the neurotag that has to be activated before it produces an output (Moseley, Butler, Beames, & Giles, 2012). In the above example, maybe just seeing a similar burger wouldn’t be enough to activate that whole network, but seeing the burger at the same food truck in the summer would activate the nauseous sensation.  

neurotag, activation threshold, brain, pain

So How Does This all Relate to Pain? 

There is a prominent approach called the neuromatrix theory of pain that takes all the concepts we explained above, and turns them into a way to explain and address pain.

Back in an earlier post we talked about how pain is not simply a representation of what is happening in our tissues, but rather a judgement about the signals from our body. Our brain makes decisions about what these signals mean. Basically, “pain is produced whenever the brain concludes that body tissue is in danger and action is required” (Moseley, 2003). 

Now combine this definition of pain with the neurophysiology described above. All the concepts like neurotags and neuroplasticity can be applied to pain. The brain is always receiving signals, or messages, from the body. These signals have the potential to trigger a “danger” or “pain” response in the brain (neurotag). If enough of the neurotag is triggered (activation threshold), then the whole network is triggered. Many areas of the brain become activated at the same time and they work together to produce pain as a way to bring your attention to the threat. Because of neuroplasticity, this whole process can change over time (Moseley, 2003; Moseley, Butler, Beames, & Giles, 2012). These concepts can guide treatment planning.


The idea that pain involves many areas of the brain interacting with each other can also be helpful when considering treatment options. It means there are many more mechanisms involved in pain than previously thought. As David Butler (2015) said, this is exciting because it “underpins the ENORMOUS power of context. Say 500 areas of the brain are in action when we’re in pain - it means that there is kind of a formula for your pain.  We’re all different, and it can be changeable.” 

So back to our initial question “is chronic pain changeable?”  As our knowledge of the brain changes, so does our view on pain. Chronic pain is not as static as once thought. Current research on the brain’s role in pain has led to new ideas and theories about treatment. This post has been all about the idea that pain can change, and why we believe this is important. In future posts, we will discuss techniques and strategies that are built on these concepts.

Acknowledgement

Diagrams by Ashley and Colleen. Graphics are from freepik.com

References

Butler, D. (2014). noijam blog: Explain Brain. Retrived from https://noijam.com/2014/12/09/explain-brain/ on April 16, 2016. 
Butler, D. via  Arthritis Victoria. (2015, August 3). Treating Pain Using the Brain - David Butler [Video File]. Retrieved from https://youtu.be/4ABAS3tkkuE on April 22,  2016. 
Cundiff, L. & Schellinck, S. (2015). The Physiology of Pain. In Occupational Therapy Best Practice: Chronic Pain Management [Course Manual]. 
Moseley, G.L. (2003). A pain neuromatrix approach to patients with chronic pain. Manual Therapy, 8(3), 130-140. 
Moseley, G.L., Butler, D., Beames, T.B., & Giles, T, J. (2012). The Graded Motor Imagery Handbook. Adelaide, Australia: Noigroup Publications.

1 comment:

  1. What a great approach to "it's all in your head"! I read about how people living with chronic pain have their pain receptors turned all the way up. We are more sensitive to pain, and more aware of the pain happening in our body. Some people may not be aware of their daily aches and pains, but there are many of us that do.

    I also tell my husband that it's the reason a massage or rubbing my feet feels so amazing to me. My body is more receptive, or more alert, to a touch - good or bad.

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