Cortical Maps

[BB]

Well, I've finally been coaxed out of the mental vacation I needed after a recent discussion on another forum that felt more like a battle than a discussion. The culprit for my mental recovery is Blakeslee's book, "The Body has a Mind of Its Own." You are all correct. This book is awesome and refreshingly short, similar to "A brief tour of human consciousness" in that way.

It has me thinking about many things that I want to discuss if anyone is interested. The first is on Mental Imagery.

From p 55

The students were then assigned to 1 of 5 groups. The first, a control group, was instructed never to play darts; they only needed to return after eight weeks to throw another fifty shots. The 2nd group threw fifty darts for thirty minutes a day, 5 days/wk, for 2 months, and kept track of their scores. The remaining 3 groups were assigned one of the 3 mental training programs. They alternated between nental training and physical practice. They would spend one day throwing the fifty darts for half an hour, and next day they would wear headsets, relax, and listen to training tapes for thirty minutes.

And the results, also from p. 55

After eight weeks, 70 students (5 had to drop out due to scheduling problems) took a post test of fifty dart throws, and the scores were tallied. As expected the control group showed no improvement. The group that threw daily improved, on average, by 67 points. The three groups that practiced along with mental training improved, on average, by 111, 141, and 165 points.

And on p. 60 an explanation of what is happening with motor imagery vs. actual physical practice:

When you mentally rehearse a movement, all but one of the brain regions that control your movements become active in the absence of movement. You imagine throwing the dart buty your body is immobile. You imagine pressing the piano dey but your muscles are still. So motor imagery is the off-line operation of your brain's motor machinery unfolding as if it were happening in real time.

And on p. 61:

When you imagine a movement, your primary motor cortex is inhibitied.. You do not move a muscle. Yet your higher motor regions are screaming along at full speed, carrying out familiar motions.

What all of this reminded me of specifically in what we are most interested in here is a quote from Patrick Wall in "Pain, the Science of Suffering." Paraphrasing it says that, when monitoring the brain activity of those in pain, their motor planning areas are lighting up, yet they are not moving.

I thought this was a very interesting similarity and has some large implications for us. It is as if, non-consciously they are taking themselves through mental imagery. A glaring difference is the net result. Those throwing darts got better by mental imageray, those in pain remain in pain. Why would that be?

More soon.

[Diane]

What all of this reminded me of specifically in what we are most interested in here is a quote from Patrick Wall in "Pain, the Science of Suffering." Paraphrasing it says that, when monitoring the brain activity of those in pain, their motor planning areas are lighting up, yet they are not moving.

I thought this was a very interesting similarity and has some large implications for us. It is as if, non-consciously they are taking themselves through mental imagery. A glaring difference is the net result. Those throwing darts got better by mental imageray, those in pain remain in pain. Why would that be?

Maybe those in pain are actually, unwittingly, practicing "pain" instead of "no pain". And getting better at it (pain) instead of 'moving' away from or out of the experience.

[BB]

Here are some things from Moseley to look through that I think may help in the answer:

http://rheumatology.oxfordjournals.o...rint/44/9/1083

http://www.ncbi.nlm.nih.gov/sites/en...ubmed_RVDocSum

http://www.ncbi.nlm.nih.gov/sites/en...ubmed_RVDocSum

http://www.ncbi.nlm.nih.gov/sites/en...ubmed_RVDocSum

[BB]

Good point, Diane. That is one direction I was thinking in as well. Before going on I'd like to add to my query.

We speak here on how the inhibition of a necessary movement expression that is already occuring mentally, but not carried out physically, allows for continued pain.

However, the dart example shows that mental imagery alone creates an effect that is as if the movement actually did occur.

Why the apparent inconsistency?

[Diane]

As I recall, the book example was to point out that physically exercising the skills inherent in throwing darts, playing a musical instrument, playing golf etc. was liable to "wear out" the important cortical neurons responsible for actually carrying out the movements (resulting in persistent and annoying dystonias like golf yips etc.); but practicing mentally resulted in enhancement of performance, while sparing the important space and grid and point motor neurons necessary to propel a physical something through space (including one's body I guess..).

In the case of pain, perhaps the habit of practicing pain mentally while doing nothing about it physically, is supported by the inappropriate coupling of this learned "efficiency" with mechanosensitivity. Just a thought.

I think this thread is going to be an important one.

[BB]

Hi Diane,

I believe that the "yips" or dystonias were more an issue of map expansion, similar to map smudging. Only it is brought on by repetition. I think it must be a similar mechanism to compulsion. But, smudging of maps in the sensory cortex makes sensation less acute, and in the motor cortex makes movement less precise.

Here is another article that's got me thinking as much as this book does.

It states that there is an incongruence between intention and action in people in pain. It has evidently been argued by McCabe that this is a possible cause of pain and there appears to be some support to this claim. However, the possibility that it is merely a correlation is supported as well. This incongruence could also be created rapidly by induced pain, and reduced rapidly by reduction of pain through anesthetic.

So, it appears a good possibility that the phenomenon is an effect and not a cause.

So, this is what I'm thinking. Consistent with Wall's 2nd stage, a smudging of the motor cortex would effectively reduce the number of movement possibilities in a way consistent with protective posturing. The result would be an incongruence in motor intention that is specific and actual movement which has become more gross/less fine tuned.

It appears, through the mirror therapy literature and others in this editorial, that reduction in pain tends to correlate with a restoration of congruence between intention and action. This sounds familiar to Barrett's theory of Simple Contact's effect.

This has me thinking about the question "if ideomotion is all that is needed then why don't people figure it out on their own?" Of course one answer is cultural inhibition or posing for other intentions than the one needed to be carried out for pain. But, I'm thinking another is a reduced movement repertoire that is created by pain. We see this all the time in our patients, and we've talked about it here as well, but not from this angle.

To answer my own question below, I think that the answer is that the dart players were mentally developing their motor planning areas, then using this to improve the action areas by actually practicing. Those in pain do not ever actually go through the movement.

[Barrett Dorko]

I should re-title my course "Creating Congruous Movement."

Therapists reading this would probably assume that the creating is done by the therapist, but, of course, I'm talking about what the patient creates. Fortunately, I already do a whole lecture on the importance of creative movement for pain relief. This thread is helping me finally understand what it is I've been talking about.

Please don't tell anybody.

The dispute between body image and body schema accounts for a number of conditions we've found mysterious and virtually impossible to treat. This has led to the use of "alternative" approaches that seem to have an effect we can't understand. Body mapping explains this, and it is undoubtedly good science

[Luke Rickards]

Moseley's editorial suggests that caution is needed in interpreting McCabe results.

The model advocated by McCabe et al. may apply to some pain states, but discordance between motor intent and movement seems insufficient alone to cause pain.

[Barrett Dorko]

That sounds good to me. I was growing concerned about the absence of origin within this model. There are plenty of people desperate to move out there who don't do so - yet they don't complain of pain.

It appears that you have to add sufficient amounts of mechanical deformation to the mix and combine that with a deficient amount tolerance (adaptive potential) in order to end up with a complaint. Can't forget about threat either.

This is a "strange alchemy" (as Walt Whitman would say) bu I think that just now we are gaining another foothold in our understanding.

[BB]

Luke and Barrett,

Sorry. I thought I had implied these things in my post.

The fact that there is an incongruence when pain is present does not seem to be in dispute. It does also occur in non-painful problems like tinnitus. Also, when the incongruence was created artificially with mirrors, many symptoms arose, only some of which were pain.

Also, the editorial gives evidence that the incongruence may be created by pain, or that they both may be created together by something else.

In my hypothetical I went with the thought that pain creates the incongruence. So, 1st comes the threat, mechanosensitivity, etc. Then comes the incongruence along with stage 2 of Wall's progression. My thought is that the incongruence would bring about the movement behavior that we see in the second stage.

The restoration of congruence then would still depend on 1st a reduction in pain, threat, mechanosensitivity. This alone appears to bring about an improvement in congruence as was seen in the anesthetic citation. However, if it is correct to assume that a reduced movement reportoire of movement results from the motor map smudging, it would make sense that movement itself would be needed to resolve this. Thus the dart thrower example and answer to my question.

This is also consistent with what is demonstrated in clinical trials. In order for the pain reduction seen with manual therapy to influence disability it must be applied to movement.

My thought is that threat is the driver for the map incongruence. When the threat is real or potential bodily harm the resulting perception is pain. Once pain is reduced, the driver is reduced. Movement awareness then helps restore the accuracy of the maps and helps restore congruence between intention and action.

So, origin and threat are preserved in this model. Also, I think it respects the editorials warning. What do you think?

[Luke Rickards]

Nice!

[Gil Haight]

Cory,

"if ideomotion is all that is needed then why don't people figure it out on their own?"
Good question. Perhaps it is primarily because we don't leave them alone to discover. Socially, we have all been lead to believe that the experts have the answers. Since science is, culturally speaking, more real than our subjective experience, the belief has become the problem.

Gil

[christophb]

Cory, I have a few thoughts on this hopefully I'm on the same page.

With the neuromatrix theory, input along the sensory discriminative pathways (mechanical deformation of tissue) can result in a output of pain along with movement intended to protect or reduce the threat. Incongruence would not be not the cause of pain but possibly the correction itself which isn't being expressed and therefore doesn't allow the reduction of the threat and therefore maintains the pain state. I think what Mosley says about habituation may be true, perhaps habituation would occur in normal’s given enough time and the system would learn that everything’s OK, and the sensations perhaps to correct the illusion of incongruence would disappear. In our patients, typically, the deformation is not illusory and it remains as does the incongruence until the corrective movement is expressed.

Does this sound about right?

Thoughts about the dart throwers vs. people in pain, the big difference I see is that one group is practicing some extrinsic goal, the other is trying to resolve some intrinsic need state.

[BB]

Hi Chris,

Incongruence would not be not the cause of pain but possibly the correction itself which isn't being expressed and therefore doesn't allow the reduction of the threat and therefore maintains the pain state.

I'm thinking this may be true. I'm also thinking that initially the incongruence is protective through limiting movement variation but may also drive the corrective process through a desire to reconcile map congruence. That would be interesting to test in the mirror studies.

perhaps habituation would occur in normal’s given enough time and the system would learn that everything’s OK, and the sensations perhaps to correct the illusion of incongruence would disappear.

I think this goes along with Barrett's "do you feel lucky" statement. I think that maps can be unsmudged in a number of ways and I would think that a gradual filling in of the missing spaces would occur during habituation. Of course, then the intended movement may be carried out, if we're lucky.

the deformation is not illusory and it remains as does the incongruence until the corrective movement is expressed.

I agree.

I think all of this demonstrates the importance of what Gil is saying as well:

"if ideomotion is all that is needed then why don't people figure it out on their own?"
Good question. Perhaps it is primarily because we don't leave them alone to discover.

It would seem that, if what we've been saying is true, 2 things must occur. 1) A carrying out of the intention, thereby bringing about congruence, and 2) a re-drawing/de-smudging of the motor maps. It would seem that if intention was able to be expressed without social inhibition that a resolution of map smudging would also likely occur gradually. But, just redefining maps alone doesn't mean the person will carry out the intended movement necessarily. Otherwise, feldenkrais exercises alone would likely resolve all mechanical pain, not just when it gets lucky.

[Barrett Dorko]

There’s a perfect storm brewing.

In the current issue of Skeptical Inquirer Kendrick Frazier discusses two recent studies in the journal Science (summary and full text available for purchase here) that demonstrate precisely what the Blakeslees’ are talking about and the text is mentioned favorably.

Even better, one of the studies created in the subject a sense of a body outside their own with a carefully constructed virtual viewing device, then they “hit” the virtual body with a hammer in view of the subject. An “emotional response” was noted by virtue of changes in skin conduction response.

How cool is that?

Oh yes, Tavris and Aronson of dissonance theory fame (discussed voluminously here) contribute a piece to this issue (Nov/Dec) and you can get it at the news stand now.

[Diane]

I think incongruence between and among maps in conjunction with pain could be between
1. cortical and subcortical maps
2. maps in the same level of the brain that don't have matching laterality
3. maps that map one kind of tissue or depth of tissue against another level or kind of tissue within the same brain part.

I think there are likely all sorts of incongruities possible that have yet to be "mapped".

[EricM]

How is an incongruency determined? I haven't finished reading the Blakeslee's book yet, but is there a map comparator in the brain? Or, is that essentially what 'brain' is, a place to compare maps?

[Barrett Dorko]

Comparator?

Eric, I really like this word, but I'm guessing you just made it up.

The resonance between thought and movement is exemplified in improvisational dance or Sacks' "perversion or inversion or subversion of will" (see this thread for more on this).

We can see and sense it in some way but I don't know that it's ever measured and "compartorated" objectively in the brain.

[BB]

Well, according to my understanding of Damasio's work, grouped mapping comparisons make up the proto, core, and autobiographical self (his categories). Maps are constantly being compared with one another as well as with themselves over time to look for differences and similarities. These differences represent patterns. Then the patterns can be compared with past similar patterns to recognize context.

I tend to think of it as transparencies on an overhead. You take 2 very similar ones and place them on top of each other. The brain notices the similar areas between the 2 and the differences. It then makes a new transparency of representing only the similar areas, and only the difference areas. These are then compared with transparencies taken from the file cabinet of experience under the desk. It finds the ones that it is similar to, then looks for the file the old experience transparency had come out of. If it was in the "danger to physical body" file the boss causes pain.

Diane,

I agree. However, do you think that the motor plan and action would come directly from these representations, or would they then send their findings to the motor cortex? I mean, can we simplify it down to think of it as the eventual motor intent/action modules will come from the motor cortex no matter where it got its info from?

[BB]

Oh, and Eric,

I think the places that Damasio and LeDoux find to be the most likely areas for comparisons, (or comparatoring) are called convergence zones. The hippocampus and its surronding area are packed with them.

[Diane]

Cory, Buzsáki would talk about cycles of EEG type waves. Coincidentally, he talks about the hippocampus not as a convergence zone but as a place of origin of the cycling.

My understanding of S1M1 (so far) is that S1 responds directly to whatever is happening in M1, and vice versa. One can't make a "move" without the other. At least I think I got that straight. It's what I remember from one of those incredibly dense and dry and precise motor books I have, not exactly page turners..

[BB]

More to chew on regarding reduced repertoire of movement and pain:

Behav Neurosci. 2006 Apr;120(2):474-6. Reduced variability of postural strategy prevents normalization of motor changes induced by back pain: a risk factor for chronic trouble? Moseley GL, Hodges PW.

Variability is fundamental to biological systems and is important in posturomotor learning and control. Pain induces a protective postural strategy, although variability is normally preserved. If variability is lost, does the normal postural strategy return when pain stops? Sixteen subjects performed arm movements during control trials, when the movement evoked back pain and then when it did not. Variability in the postural strategy of the abdominal muscles and pain-related cognitions were evaluated. Only those subjects for whom pain induced a reduction in variability of the postural strategy failed to return to a normal strategy when pain stopped. They were also characterized by their pain-related cognitions. Ongoing perception of threat to the back may exert tighter evaluative control over variability of the postural strategy. ((c) 2006 APA, all rights reserved).

[Diane]

I can't help but think about those studies Luke provided and with which I've been struggling lately;
1. the one that say puffing cold air on the face unexpectedly (engaging sympathetic response) diminishes sensitivity of cutaneous receptors
2. the one that says sympathetic blockade increases tactile sensitivity (makes sense - if they are blockaded/offline, they aren't online to diminish anything..)

Putting this together with all the stories about how pain vanishes when a greater threat (e.g., to life itself, to survival) presents itself -
1. Run from the bear, the sprained ankle doesn't even hurt at the time.
2. Your toddler runs out into the street - you forget all about your back or hip or knee pain and run out to catch the kid before it gets hit by the big bus coming down the street, running as if there had never been a pain. It is simply eclipsed for a time by a bigger "threat".

Seems to me that animals get over their pain because their brains tell them to run away from the predator, even if they are mechanosensitized. And they do, as if there was nothing wrong with them. For a few minutes at least. Probably long enough for success to have prevailed enough, to pass on the trait. A big allostatic scare will trump "pain" as a protective mechanism, if "pain" is less protective than running. The subcortical centers (insula maybe as well) make this decision all by themselves. No thought required.

We humans are so protected by our cultural shell. We don't experience physical predation threat on a daily basis, just symbolic predators, financial mostly. It makes us cranky but is insufficient to mount enough of a heightened fear-escape-success cycle to wipe out the pain, provide the motivation to move, really really move. Move for our lives. We have a pain epidemic because we do not have enough of the major stress of life and death to rev our system hard enough to get it up out of its rut. (I'm not suggesting that I'd prefer the former to the latter.)

Manual therapy is a very dilute, very staged form of this, perhaps. Just a thought. Sorry if this is off the map topic. On second thought, does anyone suppose that A Huge Stress Response (to a threat to physical existence) might fix those maps back up in a jiffy? (presuming they are out of synch with each other and that out-of-synch-ness might correlate with pain production, not necessarily cause it ...)

[nari]

If a huge threat appeared that threatened life, I suspect that remapping would occur depending on how long the threat persisted.

I remember a guy who was dysfunctional and in constant LBP for three months after the initial perception of pain. He was a typical "McKenzie" patient - lateral shift, loss of extension, etc etc. He was off work, at home with his kids. Sometime during the day, both disappeared. Immediately he set off, running and jumping fences, slithering down drains and so on. He was panic-struck.

They were found safe and sound about a mile away from home. He reported that during the frantic pursuit, he was totally unaware of any pain, and this intrigued him no end. At the time, I wasn't aware of the answer to his 'recovery', but I muttered something like: Finding the kids was a greater priority than the pain. From then on, he improved steadily.

I don't know if any remapping occurred but I suspect he worked out that he didn't need this pain.

It was one of those occasions one never forgets, clinically.

Nari

[Diane]

Nari, that's exactly what I mean. Great story.

[Luke Rickards]

How is an incongruency determined? is there a map comparator in the brain?

Eric, as far as I'm aware, the 'reafference principle' is one of the stronger theories in relation to this.

Cullen, 2004
Over 50 years ago, Von Holst and Mittelstaedt [11]
proposed that the brain generates a sensory expectation
based on the motor command, compares it with the actual
sensory feedback, and subtracts the self-generated sen-
sation. In this way, the nervous system could theoreti-
cally differentiate sensory inputs that arise from external
sources from those that result from self-generated move-
ments. Recent work in several systems has provided
evidence in support of this hypothesis, as well as evi-
dence for other mechanisms that suppress reafference in
the early stages of sensory processing. It remains a
challenge to understand how the differential processing
of sensory inputs in the early stages is used by the
upstream networks that mediate perceptual stability
and guide behavior.

[Luke Rickards]

I just remembered another implication of incongruent feedback from the ideomotor (intention-based) movement crew.

Koch, Prinz, Rosenbaum and Keller, 2006
Importantly for the concept of the subjective experience
of free will, the temporal attraction between actions and
their effects appears to be contingent upon the actions being
voluntary. Haggard et al. (2002b) demonstrated that
temporal attraction is reversed, – thus, becoming temporal
repulsion – when “effects” (tones) are triggered by transcranial
magnetic stimulation (TMS) of the motor cortex
(which induces involuntary muscle twitches) rather than by
intentional, self-paced, key presses. This finding suggests
that action-effect binding may be the mechanism behind
the experience of one’s own causal agency: Events that
match the anticipated effects of an action are attributed to
the self, whereas events that do not match such predictions
are attributed to an external source (see Frith, 1992). More
specifically, it may be the activation of combined actioneffect
representations that leads to the conscious awareness
of the intention to act (see Haggard et al., 2002b). If so,
intention-based and stimulus-based actions should differ
not only in behavioral indices, such as temporal attraction
measures, but also in terms of their electrophysiological
signatures.

[Diane]

Luke, you find the best stuff...

All I can offer is this partially eaten and digested carcass of a thread I started ages ago, and didn't finish, because I got so lost in it I think... I still don't really get any of this, much, yet. (I get terminally confused when I try to see the brain as a movement producer first, rather than as a sensor first, as is my usual habit, and unsubstantiate-able.)
Moving right along.

Seems to me that the biggest glitches in the system happen between cortical and subcortical, or else inTRAcortically. In fact, intracortically is where I'd lay most of my odds, with the subcortical functions coming in to take over when they see that the newest brain part can't cope. Which keeps the organism alive, alright, but results in that annoying mechanosensatization, pain with movement.

Not really knowing anything (permanent, terminal beginner's mind) I'm going to ponder it all as though S1 and M1 were only separable conceptually, not in fact, see where that line of thought goes.

Maybe handling skin stirs M1 and S1 in a simultaneous and equivalent way. Maybe S1M1 needs to "feel" itself separate for a little while before the cortex can take its task up again, i.e. motor inhibition and downregulation among other things. The whole point of the cortex is, after all, to command voluntary function. It sees pain as a mutinous act. The subcortical structures see it as necessary for preservation of life, with the exception of when a stronger threat to existence emerges, whereupon it will default to a no-pain state for a time or else longterm.

The brain parts are a family and can't just leave each other behind. Manual therapy, especially skin deep manual therapy, is relationship counseling for them, somehow.

[Nick]

So, apparently I've fallen drastically behind in my reading.

Can someone give a brief explanation of map incongruence while I await my newest book?

[BB]

Hi Nick,

Map incongruence was the topic of the editorial by Moseley posted a bit back. It basically says that people in pain display an incongruence in the mapping of their intentions and of the actions that they actually perform.

[Jason Silvernail]

Nick-
You're not the only one. This thread left me behind at post #1.


This is why I love Soma. I'm always finding things I have no clue about that seem perfectly relevant to practice yet aren't discussed anywhere else.

[nari]

Jason and Nick,

Ditto what Jason said.
But with time I will make sense of it - I think.
Somehow I get the feeling that I know what is being implied, but the lingo leaves me behind.

Nari

[bernard]

I think and was told that every movement is carried with an immobile one: It is why we observe skin resistance changes, circulatory...

It comes why the preparation of a movement, even with a virtual one.

It implies a congruence within the premotor and "effective" areas.
Many silent input are carried (and waited) with this immobile movement as in the effective motion.

[bernard]

Cereb Cortex. 2007 Sep;17(9):2214-22. Epub 2006 Nov 23.
Related Articles, Links

The sight of others' pain modulates motor processing in human cingulate cortex.

Morrison I, Peelen MV, Downing PE.

Centre for Cognitive Neuroscience, University of Wales, Bangor, Bangor, Gwynedd LL57 2AS, UK.

Neuroimaging evidence has shown that a network including cingulate cortex and bilateral insula responds to both felt and seen pain. Of these, dorsal anterior cingulate and midcingulate areas are involved in preparing context-appropriate motor responses to painful situations, but it is unclear whether the same holds for observed pain. Participants in this functional magnetic resonance imaging study viewed short animations depicting a noxious implement (e.g., a sharp knife) or an innocuous implement (e.g., a butter knife) striking a person's hand. Participants were required to execute or suppress button-press responses depending on whether the implements hit or missed the hand. The combination of the implement's noxiousness and whether it contacted the hand strongly affected reaction times, with the fastest responses to noxious-hit trials. Blood oxygen level-dependent signal changes mirrored this behavioral interaction with increased activation during noxious-hit trials only in midcingulate, dorsal anterior, and dorsal posterior cingulate regions. Crucially, the activation in these cingulate regions also depended on whether the subject made an overt motor response to the event, linking their role in pain observation to their role in motor processing. This study also suggests a functional topography in medial premotor regions implicated in "pain empathy," with adjacent activations relating to pain-selective and motor-selective components, and their interaction.

PMID: 17124286 [PubMed - indexed for MEDLINE]

[bernard]

http://www.ncbi.nlm.nih.gov/books/bv...i.section.1190

Thus, in contrast to the neurons in the primary motor area, when a monkey is trained to reach in different directions in response to a visual cue, the appropriately tuned lateral premotor neurons begin to fire at the appearance of the cue, well before the monkey receives a signal to actually make the movement.

=> unconscious movements.

[Jon Newman]

Last year Barrett Dorko posted this at NOI:

Perhaps this will add something to the topic.

From John R. Searle’s “The Mystery of Consciousness” in the chapter “Consciousness Denied” concerning the ideas of Daniel Dennett (a highly regarded philosopher and, along with Richard Dawkins, the originator of the study of memetics), “His claim is in fact we are zombies…that there is no such thing as conscious life; there is only complex zombiehood. (His) idea is that pain is not the name of a sensation but a matter of having one’s plans thwarted and one’s hopes crushed.”

In a very real sense pain is a consequence of inaction - if that action would have relieved the pain. To me, this sounds like what movement therapy is for.

Perhaps it will add something to this topic also?

[Barrett Dorko]

Yea Jon, what you said, or, rather, what I said, or Searle said what Dennett said, that I then said, sort of.

It's nice to know that somebody's reading and remembering all this old stuff because I certainly can't keep track of it.

Dennett's description of "plans thwarted" fits perfectly with the concept of "defense or defect" in evolutionary reasoning that I teach. Without seeing the system in pain this way it's easy to misinterpret the muscular action we see and feel.

[Diane]

In case no one else has already linked to this paper from Pain that Luke brought, I'll slot it in: Pain and Motor System Plasticity.
It doesn't mention maps specifically, but I'm sure it has something to do with this thread.

(I'd not have remembered it except that it is a current thread again.)

[Jon Newman]

Dennett's description of "plans thwarted" fits perfectly with the concept of "defense or defect" in evolutionary reasoning that I teach. Without seeing the system in pain this way it's easy to misinterpret the muscular action we see and feel.

Hi Barrett,

I've included some relatively recent research here. I'll post some thoughts after I've actually read and digested some of it.

[BB]

I'd like to look into the moseley movement variability article. I think there are some very interesting similarities.

First, an experimentally induced pain reduced variability of postural strategy. 2 groups were identified. One, resolvers, regained the variability when pain stopped. The other, non-resolvers, did not.

The reduction in variability manifests as a reduction in trunk torque and an increase in stiffness.

I find this very interesting, because if this reduction in variability is manifest cortically as a "smudged" motor map, then this study may be describing the physical correlates of motor-sensory incongruence.

Right now I don't have an article to link the two together, but I remember hearing Lorimer describe such a thing. We'll see how accurate my memory is.

Also interesting is what was predictive of who would be a resolver and a non-resolver. It was their beliefs about pain.

Am I being clear of why this has got me so excited? If not let me know and I'll try again. I think that this is an article that describes what we discussed below!

[BB]

Here are some conclusions I've come to and questions I've generated so far. Comments are welcome, as always.

Sensory-Motor Incongruence...what is it? A mismatch between intended movement (predicted movement as described in bernards abstracts below) and actual movement.

Motor planning involves predicting an outcome. The motor cortex is driven to move based on this prediction. See goal states, end state comfort effect.

As the actual movement is occurring, sensory feedback is occurring.

This information of the movement that actually was performed is compared to the predicted/intended movement. Differences are noted. The differences are called efference.

Question: Efference is normal to a degree. An abnormal degree of efference or a recognition of past threatening associations could generate pain conceivably, couldn't they?

Pain causes such an efference experimentally, and it disappears when pain is relieved (moseley editorial).

Pain has been shown to reduce variability of movement and increase stiffness in those with certain beliefs about pain.

Question: Are these (decreased variability and stiffness) signatures of motor cortex representation smudging?

[bernard]

Cory,
Modifying muscle tone is only necessary to increase stiffness and reduce variability at the same time =>

http://www.somasimple.com/forums/sho...9&postcount=21
http://www.somasimple.com/forums/sho...9&postcount=22
http://www.somasimple.com/forums/sho...4&postcount=23

ps: some animations have several stages, you need to click the play button to see the next.

[BB]

Thanks Bernard. Damn, you're good with animations!

I'm trying to consider all this may mean.

[BB]

Modifying muscle tone is only necessary to increase stiffness and reduce variability at the same time =>

Agreed! And the Moseley has shown that this stiffness is present along with with reduced variability and has shown even the the change is manifest by a change in function of the deep and superficial muscles.

At the start of a movement, brain knows already if the movement will be correctly achieved because it has calculated the trajectory and the possible goal.

If brain knows that the movement will inevitably fails, is it really necessary to try it or is it another way to say it?

This is exactly why variability is crucial. An increased repertoire of movement giving the body options. In absence of options stiffness remains.

What I'm real curious about is how this stiffness is represented in the brains motor maps. Smudging of the sensory maps increases the representational area, intruding into neighbors to create phantom sensations and such. It would make sense that the same phenomenon in the motor cortex would manifest as the stiffness that we see. Would it not?

[bernard]

Originally Posted by BB

What I'm real curious about is how this stiffness is represented in the brains motor maps.

IMHO, it is not located there but in cerebellum.

Neurosci Res. 1998 Mar;30(3):257-69.
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Augmentation of postural muscle tone induced by the stimulation of the descending fibers in the midline area of the cerebellar white matter in the acute decerebrate cat.

Asanome M, Matsuyama K, Mori S.

Department of Biological Control System, National Institute for Physiological Sciences, Myodaiji, Okazaki, Japan.

In a reflexively standing acute decerebrate cats, the cerebellar white matter was systematically stimulated and the effects on the level of postural muscle tone were studied. A stimulating microelectrode was placed systematically at 0.1-0.5 mm increments from H + 2 to H - 2 at levels ranging from P7.0 to P8.0 rostrocaudally and mediolaterally from LR0 to L1.5 or R1.5. Stimuli delivered to the restricted region of the cerebellar white matter along its midline resulted in simultaneous and bilateral augmentation of tonic activities in the neck, lumbar back, fore- and hindlimb extensor muscles along with increased levels in the forces exerted by each of the left and the right fore- and hindlimbs. Effective stimulus regions were located in the cerebellar white matter rostral and ventral to the most rostral part of the fastigial nucleus. Microinjection of a retrograde neural tracer, cholera-toxin b subunit conjugated horseradish peroxidase (CTb-HRP), into the lesioned effective stimulus sites resulted in a retrograde labeling of cells in the fastigial nuclei, bilaterally. All these results suggest that the augmentation of postural muscle tone was evoked by a selective activation of fastigiofugal fibers which course through the 'hook bundle'.

Publication Types:

• Research Support, Non-U.S. Gov't

PMID: 9593336 [PubMed - indexed for MEDLINE]

[bernard]

Med Pregl. 1990;43(3-4):172-4.
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[Regulation of muscle tonus]

[Article in Croatian]

Krkljes M.

OOUR Institut za neurologiju, psihijatriju i mentalno zdravlje, Novi Sad.

The regulation of muscle tonus takes place at least at six levels of the central nervous system: the spinal cord, vestibular nuclei, the cerebellum, the reticular formation, extrapyramidal system and the motor cortex. A multiple complexity of the connections of these systems in the regulation of muscle tonus is presented, so that therapy can be usefully applied in states of muscle tonus disorders.

Publication Types:

• English Abstract

PMID: 2233558 [PubMed - indexed for MEDLINE]But you're right, too.

[bernard]

Postgrad Med J. 1977 Dec;53(626):713-8.
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Physiology of abnormal movements.

Marks J.

The units of the central nervous system controlling voluntary movement are described and the roles of the motor and sensory cortex, of the basal ganglia and cerebellum and of the final common loop are outlined. The pathophysiology underlying disturbances of movement, power and tone of the limbs is discussed, with particular reference to the more common dyskinesias.

Publication Types:

• Review

PMID: 343077 [PubMed - indexed for MEDLINE]

[bernard]

Zh Nevropatol Psikhiatr Im S S Korsakova. 1977;77(6):826-32.
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[Hierarchy of nervous system structures in regulating muscle tone]

[Article in Russian]

Khrolenko DE.

An analysis of mechanisms regulating the muscular tone, conducted on the basis of a study of the phylogenesis of nervous structures, as well as on experimental and clinical studies of the mascular tone in normal conditions and in pathology permitted to distinguish the following 6 levels of muscular regulation: segmento-peripheral, general suprasegmental, cerebellar-stem; pallidal, strial, cortical. The author discusses some clinical syndromes of disturbed muscular tone (parkinsonism, hormetonia, decerebrated regidity). It was demonstrated that each higher level exerts an inhibitory action on the lower level of muscular tone regulation and in this way there is a distinct ierarchy of the tone regulation. The ierarchy system of muscular tone regulation should be taken into consideration when determining the level of the nervous system lesions and in intervention in order to normalize the muscular tone.

Publication Types:

• Comparative Study
• English Abstract

PMID: 899486 [PubMed - indexed for MEDLINE]some old studies may help?

[bernard]

Eur J Pain. 2007 Oct;11(7):743-55. Epub 2007 Jan 16.
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Autonomic activation and pain in response to low-grade mental stress in fibromyalgia and shoulder/neck pain patients.

Nilsen KB, Sand T, Westgaard RH, Stovner LJ, White LR, Bang Leistad R, Helde G, Rø M.

Norwegian University of Science and Technology, Department of Neurosciences, N-7489, Trondheim, Norway. kristian.b.nilsen@ntnu.no

OBJECTIVE: Psychosocial stress is a risk factor for musculoskeletal pain, but how stress affects musculoskeletal pain is poorly understood. We wanted to examine the relationship between low-grade autonomic activation and stress-related pain in patients with fibromyalgia and localised chronic shoulder/neck pain. METHODS: Twenty-three female patients with fibromyalgia, 29 female patients with chronic shoulder-neck pain, and 35 healthy women performed a stressful task lasting 60min. With a blinded study design, we recorded continuous blood pressure, heart rate, finger skin blood flow and respiration frequency before (10min), during (60min) and after (30min) the stressful task. The physiological responses were compared with subjective reports of pain. RESULTS: The increase in diastolic blood pressure and heart rate in response to the stressful task were smaller in fibromyalgia patients compared with the healthy controls. Furthermore, fibromyalgia patients had reduced finger skin blood flow at the end of the stressful task compared to healthy controls. We also found an inverse relationship between the heart rate response and development and recovery of the stress-related pain in fibromyalgia patients. CONCLUSION: We found abnormal cardiovascular responses to a 60min long stressful task in fibromyalgia patients. Furthermore, we found a negative association between the heart rate response and the pain which developed during the stressful task in the fibromyalgia group, possibly a result of reduced stress-induced analgesia for fibromyalgia patients.

Publication Types:

• Research Support, Non-U.S. Gov't

PMID: 17224287 [PubMed - in process]

Something that we already know?

[bernard]

Originally Posted by BB

Thanks Bernard. Damn, you're good with animations!

Cory,

They may be improved.
You have to consider this example as a simple one (that's normal on this site).

A movement is a collection of sub-movements that are associated to produce a sequence. Perturbing a single step perturbs the whole sequence.
The animation is incomplete since it shows only two situations:

1. movement done without problems
2. movement undone

But the most interesting is the one that is done with problems:
You can imagine a curve that reaches the goal but that has incidents (not smooth).