Practical Science on Movement and Pain

Review of Moseley/Hodges Talk Part Three

This is part three of my review of the Lorimer Moseley and Paul Hodges conference on pain and motor control. You can read parts one and two here and here. This section will describe Lorimer’s discussion of the body maps and their connection to pain, motor control and immune responses.

The brain’s map of the body

Like pain, body perception is an output of the brain, not an input. It is something that the brain constructs based on information from the body, not something that is given. Various names have been assigned to the neural structures or neurotags which create this output – body maps, cortical body matrix, virtual bodies or body schema.

Moseley discussed a great deal of research showing how the cortical body matrix is intimately connected to various other outputs of the brain that basically comprise everything we care about in relation to manual therapy or corrective exercise – pain, coordination, and immune responses such as inflammation. Prepare to have your mind blown if you haven’t read up on this stuff before.

Phantom movement maps

Body perception and movement ability are fundamentally linked. We can only do what we can imagine doing. Here’s an interesting example. Moseley asked phantom arm owners to try to move their phantom hands into physically impossible configurations. First they were unable to do so, but with practice some of them succeeded, presumably due to changes in the way the arm was represented in the brain. Their newfound ability coincided with a subjective inability to perform normal movements with the phantom limb. The lesson – we can only move in accordance with our maps. If there is no map for the movement, it cannot even be imagined, much less executed.

The sense of ownership

One fundamental aspect of perceiving the body is the sense of ownership over body parts. We take it for granted that our brain knows which physical objects in its vicinity are part of the body and which parts are not. But the sense of ownership is not so simple. Moseley has shown that it is fairly easy to encourage the brain to take “ownership” over inanimate objects, and “neglect” actual body parts. One of the best ways to cause this confusion is with the rubber hand illusion.

Rubber hands and neglect

I have previously discussed the rubber hand illusion. This involves placing one hand on a table, the other out of sight behind a screen, and a rubber hand to the side of the hand in sight. The subject’s hand behind the screen is then stroked with a brush while he watches the rubber hand stroked in the same way. Pretty soon he will get an uncanny sense that the rubber hand is part of his body, and he will even flinch when it is threatened.

What has happened here is that the brain has basically taken ownership of the rubber hand. This is amazing enough, but what I find particularly incredible is that the brain also disowns or “neglects” the hand that is out of sight. How do we know this? There is a change in blood flow to the neglected hand. Yep, the hand behind the screen actually gets colder. And it just gets weirder. It turns out that coldness and neglect are a two-way street, so that it is easier to experimentally induce neglect in a hand that is already cold, than in one that is warm.

Here’s another cool experiment. A hand which has been disowned through the use of the rubber hand illusion will suffer less inflammation in response to a physical insult then a normal hand. Wow.

But what relevance does this have to situations not involving deliberately constructed illusions? Lots. Research shows that similar forms of neglect and map confusion are involved in many common forms of pain.

Chronic pain and fuzzy back maps

Try to imagine the outline of your back. Some parts will seem clear and others might seem fuzzy, harder to define. Research shows that your the ability to form a clear outline of the back will decrease in the area of chronic pain.

Moseley discussed a great deal of other research showing map disturbance in cases of chronic pain. For example, subjects with one sided back pain tend to locate their vertebra closer to the painful side than the non-painful side. Two point discrimination (the ability to know whether you are being poked with two needles or one) is less sensitive in areas where there is chronic pain. There are many other studies showing that pain is associated with disturbances in the cortical body matrix, and that body parts in pain tend to get neglected

Why the neglect?

So why does the brain neglect body parts that are in chronic pain? I have previously speculated that this is due to sensory gating – more nociception means less attention to proprioception, which means less information necessary to fill out the details of the body map. But Moseley introduced another speculation to account for poor body awareness in areas of pain: that neglect serves a useful protective purpose. To describe this idea Moseley used the example of a patient with CRPS (complex regional pain syndrome). Such patients can experience pain and inflammation of their affected limb simply by thinking about itPerhaps neglect is a way to avoid the overactivation of pain and immune response neurotags that have become too facilitated or imprecise. (Recall that neglected hands suffer less inflammation in response to a wheal.)

And consider this study that Moseley also discussed. Subjects with CRPS who view their affected hand with magnifying glasses experience increases in their pain, while wearing “minimizing” glasses will reduce pain. It seems that greater awareness of the hand creates more pain. Perhaps neglect is a way to protect the hand from too much awareness. Interesting idea, and a caution that body awareness, like movement, can be a double-edged sword, capable of causing harm if it is to threatening.

Maps of space

Apparently the brain’s outputs in regard to a certain body part, including the sense of ownership, extend not just to that body part, but to the area of space associated with that body part.

In other words, if you have a painful or neglected right hand, you might also have a painful or neglected right “space” around the hand. Patients with CRPS tend to neglect their painful limb and it is consequently usually colder than the unaffected limb. Guess what happens when you have a person with CRPS sit at a table and swap the positions of their hands for 10 minutes? Their unaffected hand gets colder, showing that the patient not only has a cold right hand, but a cold right side.

Other research shows that if you move a neglected hand close to a certain part of your back, then your two point discrimination in that part of your pack is reduced. In other words the brain will continue to neglect the space of the painful right hand wherever it goes.

I think it was at about this point in the presentation when Lorimer asked his audience – “Now how hard is your job?” The hard reality is that the body is not a simple machine, and mechanical factors are just a small part of the whole pain story. Unfortunately, we can’t fix back pain by just stretching the hip flexors and strengthening the abs. It ain’t easy folks!

Coming up next

That’s it for now. In the next part I will try to wrap up the Moseley talk with his discussion of nociception, the variety of ways it can be modified, and the ways we can classify the different kinds of pain.

Read part four here.

If you want to read more about pain and some of Lorimer Moseley’s research, check out some of the posts below:

Great Ted Talk on Why Things Hurt

Great New Paper on Targeting the Brain for Treatment of Pain

The Thermal Grill Illusion

The Rubber Hand Illusion

More on Pain and Illusions

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19 Responses to Review of Moseley/Hodges Talk Part Three

  1. davie nolan says:

    Really interesting Todd, thanks for this.

  2. Dave Nolan says:

    Todd, do you think your practice will evolve from being on the course and if so how?

  3. Todd Hargrove says:

    Good question Dave. Well I knew most of this stuff before going to the course anyway, so it doesn’t cause that much of a paradigm shift. But it does emphasize that I want to get better at giving my clients pain education.

  4. ian stevens says:

    Sandra Blakeslee’s book covers all this really well and I am sure you have it Todd.
    Dave ,for me and not being boastful or anything I am well versed in all this stuff and I would go along to see the reaction of people who dismiss it all —it has to be delivered by someone with charisma and authority for people to take any notice . Even then its hard to tell as David and Lorimer have taught here and the effect in the long term is negligible !

    • Todd Hargrove says:

      Hi Ian,

      Yes Blaskeslee’s book is a gem. It’s hard to integrate new ideas if they require throwing out old cherished ones. I think Silvernail’s analogy of crossing the chasm is a good one.

  5. Becky L says:

    Just wanted to say that the effect on me of dicovering this website, and being introduced to Lorimer/Feldenkrais etc. has been anything but negligible! But yeah, other people have looked at me strangely when I’ve tried to explain it to them…

  6. TMS Mike says:

    I have been a big believer in Dr. Sarno’s Mind Body Connection since reading his book helped me overcome my back pain 10 years back.

    Really enjoying this blog and the discussions. Thanks.

  7. darius says:

    seriously great stuff. i’ve been dabbling with this for maybe 6 or so years since i learned some alexander technique and then meditation/hypnosis. i still have chronic pain issues and try to play around with my internal body maps using NLP techniques to see what changes i can bring to both my relationship-to-the-pain/sensations (stories i am telling myself about the pain/sensations) & the sensations themselves, as well as how it all effects performance. i haven’t gotten very far, but the best is when i’m in a particularly altered state and seem to have much more space between my Self and my “State”. if that makes any sense.

    i’m hoping to start some feldenkrais here in SF soon, to see if i can discover anything new. looking forward to more blog posts.

    • Todd Hargrove says:

      Thanks Darius,

      More coming soon!

      Sorry to hear about the chronic pain. Sounds like you are using a great approach though. Best of luck.

  8. Rod says:

    Hey Darius,
    You probably dont understand how profound your statement about the seperation of self from state is, but it is the key to going to the next level in understanding all this. Excellent.

    • darius says:

      thanks! i aim to be humble about any achievements i may have made in this life, but in reviewing my own history as well as talking with others and internet researching, i do think it is a particularly novel yet ancient altered state to realize.

      i often muse about my pain, as if it were just any other sensation, as it if were just any arbitrary story… thinking along the lines of “maybe what i’m feeling is actually pleasure, or actually something else, but something in me is choosing to register it as painful…” things like that.
      it doesn’t necessarily change the intensity of the pain signals, but it changes the meaning of the pain signals.

      my greatest goal in life is to be able to be self-aware, and maybe the pain is my personal mechanism to remind me to be a good person and make ethical decisions regardless of “how i feel”. it’s easy to be ‘nice’ when you feel ‘good’, it’s challenging to be nice when you feel bad. so even if i feel bad all the time, i still want to behave ethically, so my state of health may really be my personal “shaolin training” in this area..

  9. Sophie Rose says:

    I found the comment regarding body awareness potentially maximising chronic pain interesting. I’ve always been under the impression that improved awareness will lead to the body maps in the brain becoming clearer which leads to less pain. I can’t help thinking that perhaps the magnifying class experiment isn’t necessarily increasing ‘true’ body awareness to the hand (at least from a felt, proprioceptive standpoint) in a way that would improve the clarity of the body maps in the brain? But instead by visually ‘enlarging’ a sore area you trick the brain into thinking there’s a larger area to be sore, resulting in more pain – I imagine making a cut or graze appear larger than it is would have the same effect.

    • Todd Hargrove says:

      Hi Sophie,

      That is my bias as well – that accurate info is always good. But lorimer suggested that neglect is a protective mechanism. If that is true, then accurate info may take that protection away, which is a bad thing. Sometimes mere awareness is an exposure that is to too threatening at a particular stage.

  10. Becky L says:

    What Darius says is really interesting – trying not to let pain control how you act. From my experience, pain massively alters how you feel about yourself, and then that in turn (if I read Feldenkrais corrrectly) affects your posture and self-image, and then of course it affects your pain.
    And it is a journey to work through these things because they are incredibly complex.
    I am finding it a real challenge to do the Feldenkrais exercises, because there are so many times when I’m tired or cold or annoyed and can’t relax my mind enough to get into it. So the progress is slow! However, what I’ve experienced on the successful days has been so striking that it gives me a lot of drive to carry on.
    I am now trying to challenge my habits, of both thought and action, in as many situations as I can! The stuff I’m learning here has made me feel a lot more in-control of my progress in a way that physiotherapy exercises/advice never did.

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