Wednesday, April 16, 2014

"We are nature" and nature is fractal, so let's work with that idea



Yes, we are nature.
We are a connection of cells, in relationship with each other. Cells that have decided to live together in a coordinated fashion to enhance their own lives. The ultimate coordinator, supporter, manager, protector and initiator of all this multicellular existence and function is the nervous system, and, before it, ectoderm. 

The river running through us, and through each nerve, through our whole nervous system, is our blood supply. 

At every level of function, a more complex version of this nervous system can interrupt and substitute another pattern upon a function - provided all the cells can make the right kind of proteins, and provided the immune system remains obedient to the nervous system, and doesn't try to stage some kind of coup d'état.

.......

Out in the social world, things often seem organized along similar principles. In fact, society (any society, based on any idea, in any era) seems to make every effort to convince us there is a vast social order with us residing at the bottom.
Mostly, schooling reinforces this. Please see Seth Godin's remarkable little free e-book all about this; Stop Stealing Dreams. It's great. He would like to see schooling change, a lot. So would I.

Here are a few excerpts, and some thoughts I have about the profession I inhabit. And am trying to not just redecorate, but renovate, from the studs out. From:
Stop Stealing Dreams - - Seth Godin



EXCERPTS:

1. "Be ashamed to die until you have won some victory for
humanity." Horace Mann, Civil War era, who installed public schooling.

2. " To efficiently run a school, amplify fear and reduce passion....fear must be used to keep the masses in line... the flip side.. is that passion will be destroyed. There's no room for someone who wants to go faster, ..do something else, or someone who cares about a particular issue."

3. "There really are only two tools available to the educator.
"The easy one is fear.”
"Fear is easy to awake, easy to maintain, but ultimately toxic."
"The other tool is passion. A kid in love with dinosaurs or baseball or earth science is going to learn it on her own. She’s going to push hard for ever more information, and better still, master the thinking behind it."

4. "The industrial structure of school demands that we teach things for certain. Testable things. Things beyond question. After all, if topics are open to challenge, who will challenge them? Our students. But students aren’t there to challenge—they are there to be indoctrinated, to accept and obey... The obligation of the new school is to teach reasonable doubt. Not the unreasonable doubt of the wild-eyed heckler, but the evidence-based doubt of the questioning scientist and the reason-based doubt of the skilled debater."

My "profession" (physiotherapy) is WAY tilted toward factory style learning and delivery. When I think about it, I'm rare in that my passion managed to stay alive somehow... I carefully nurtured it, like some subversive. I have a LOT of gripes about my profession, and now I see that most of them revolve around style, same style as Seth Godin is saying is obsolete, not because my interior human primate social grooming instincts were wrong. (These instincts were right all along. The style of "training" almost killed them! Good example - the deliberate imposition of biomechanical thinking upon otherwise [already perfect] human primate social grooming in manual therapy. Teaching groomers to groom too hard, too fast, too deep, too operatively. Not letting the brains of the patient, their critter brain and human brain, the opportunity to make new sense from new input, together, and mutually pleasantly. )

5. "One of the things that school is for is to teach our children to understand and relish the idea of intellectualism, to develop into something more than a purpose-driven tool for the industrial state."

The zombie model.
Is it any wonder zombie movies are so popular?
I caught up on movies while flying to and from Brazil. One of them was WorldWar Z with Brad Pitt.
Maybe zombie movies are a clue that pushback is happening against the outer social world having tried to turn us *into* zombies. Or at least intellectually suppressed, domesticated humans.

6. "An artist is someone who brings new thinking and generosity to his work, who does human work that changes another for the better. An artist invents a new kind of insurance policy, diagnoses a disease that someone else might have missed, or envisions a future that’s not here yet. And a linchpin is the worker we can’t live without, the one we’d miss if she was gone. The linchpin brings enough gravity, energy, and forward motion to work that she makes things happen."


Can any physiotherapist be either, given our (ahem) "training"?
Remember, our training teaches us:
1. Outdated concepts
2. In order to pass exams
3. To prepare us for an industrial version of health care
4. That has little or nothing to do with actual individuals or their needs to have their main positive feedback loop interrupted.
... See Erik Meira's blogpost about positive feedback loops, http://ptpodcast.com/getting-rid-of-something-positive/ , fear being the main one, and how we must break these loops to help people return to "thoughtless, fearless movement" as per Louis Gifford (2005).

Passion and drive and some intelligent reworking of concepts, plus some decent information about how the nervous system works, how pain works, could reverse a lot of zombie-like behaviour in my profession and restart its engine, rekindle peoples' intelligence/critical thinking, ability to entertain doubt, embrace uncertainty, reboot PT's effectiveness out there in the world. Support its capacity to become way more than it is right at the moment..

7. "What we *do* need is someone to persuade us that we *want* to learn those things, and someone to push us or encourage us or create a space where we want to learn to do them better."

Exactly what the PT profession needs... more teachers willing to be honest about how zombified our profession made us/we let ourselves become, how we each have to take steps that point away from this.

8. "In a post-industrial school, there is no us and them. Just us."

And in an ideal post-graduate manual therapy class, there is no "patient" vs. "professional"; there is only the nervous system, and how to learn to help it work smoother so it doesn't bother the person living inside it so much.

What a lot of work it would save everyone if this were just taught matter-of-factly at the
undergraduate level!

9. "Every great teacher you have ever had the good luck of learning from is doing the irreplaceable labor of real teaching. They are communicating emotion, engaging, and learning from the student in return. Emotional labor is difficult and exhausting, and it cannot be tweaked or commanded by management."
"As our society industrialized, it has relentlessly worked to drive labor away and replace it with work. Mere work. Busywork and repetitive work and the work of Taylor’s scientific management. Stand just here. Say just that. Check this box."
(Evaluation forms, anyone?)
"I'm arguing that the connection revolution sets the table for a return of emotional labor. For the first time in a century, we have the opportunity to let digital systems do work while our teachers do labor."
"But that can only happen if we let teachers be teachers again." - Seth Godin

As PTs, we are educators crossed with animal trainers. I say that because mostly we deal with critter brains in people. Just because they are in people doesn't mean they aren't critter brains. We want them to stop biting the person trapped in there with them.
We have to educate nervous systems out of doing whatever they are doing that doesn't work, and help them learn how to do something else. That "something else" is not under our direct control. It will always be under the control of that particular nervous system, unique and individual. All we can do is our best, and hope for the best. Nothing is for certain.
Still, we have to do our best.

At the profession level, we have to stop seeing ourselves as trained monkeys, eager to perform for mere cucumber slices or grapes dished out only if the “health care” system approves of our behaviour, and develop our reasoning and critical thinking capacities. How else will this profession truly grow up and become a real profession?

10. "Leadership isn’t something that people hand to you. You don’t do followership for years and then someone anoints you and says, “here.” In fact, it’s a gradual process, one where you take responsibility years before you are given authority. And that’s something we can teach."

11. "The librarian isn’t a clerk who happens to work at a library. A librarian is a data hound, a guide, a sherpa, and a teacher. The librarian is the interface between reams of data and the untrained but motivated user."

My sister is a librarian.

12. "Five years from now, electronic readers will be as expensive as Gillette razors, and e-books will cost less than the blades...Librarians who are arguing and lobbying for clever e-book lending solutions are completely missing the point. They are defending the library-as-warehouse concept, as opposed to fighting for the future, which is librarian as producer, concierge, connector, teacher, and impresario... "We need librarians more than we ever did. What we don’t need are mere clerks who guard dead paper. Librarians are too important to be a dwindling voice in our culture. For the right librarian, this is the chance of a lifetime."


We need PTs too. What we don't need are zombie PTs who fill out paper reports and forms and micro-manage. We need PTs who are willing to stick their necks out and teach more people how to be caring human primate social groomers, and to he11 with any negative opinions on my choice of language for *this* valuable service we can easily provide, once we know what is actually entailed..

"I don’t know what your destiny will be, but one thing I know: The only ones among you who will be really happy are those who sought and found out how to serve."– Albert Schweitzer, via Seth Godin
.............

Sunday, April 06, 2014

Reflection on meeting Jan Dommerholt: Trigger points II

The computer appeared to be working much better this week. I'm all set to go to Brazil tomorrow, stick loaded. Last minute fussing over this and that. Had a moment of panic when I couldn't find my ziplock bag with the adaptors and phone charger in it. Looked all over. Finally found it in the new computer bag I bought on my way home from the Vancouver MTABC Pain Conference last weekend, while I was killing some time waiting for the finishing touches on my dead computer. Turned out it wasn't dead after all.. just comatose again. It smartened up with a new library rebuilt by the technician. So, yay.. staved off having to buy a new one, yet again.

Anyway, the weekend went well, I think.. Doug Alexander from TouchU.ca is going to put all the presentations online, accessible by the conference attendees for a year, and available as online courses to anyone.

A highlight was that I got to meet and have a nice long conversation with Jan Dommerholt, who up until now had had email exchanges with years ago, but had never met in person. He was very nice to me.

I still don't buy the idea that "trigger points" of the sort that are palpable are actually in muscle, despite his protestations that a) he can palpate them there, and b) he can prove they are in muscle through modern day imaging. The only picture of one (supposedly one), is from the 1950's.. he had it in his presentation.  



Here is a pic someone took of us after lunch. He is in a wheelchair these days because he is recovering from a hip fracture sustained in a freak car accident five weeks prior.
From Jan's presentation I learned several things -
1. he does not discount any sort of input into the left side of the neuromatrix, including cutaneous input 
2. he does include nervous system considerations, including the neuromatrix model itself 
3. he admits there are "trigger points" that are too deep for him to get a fix on/palpate 
4. the work done so far has shown that contracture in striate muscle is *not* because of acetylcholine leakage at motor end plates (i.e., at least one hypothesis is disproved) 
5. the "bibles" by Travell and Simons need a massive update, which is unlikely to happen, as long as they keep selling the way they still are/do. Lots of $ for the estate.  
(I forgot to ask him, but this may be the source of all that money the trigger point people use to fund all the research they do on trigger points.)
He took us through the history of his meeting with Travell and Simons and becoming hooked up to their enthusiasm. They found an inexhaustible promoter-scholar-researcher in Jan, that's for sure.

ON THE CURRENT STATE OF "NEEDLING"
He teaches courses in dry needling. From our conversation I learned he feels despair (as we all do) about all the needling going on out there that is not accompanied by any neuroscience or pain science (he makes people pass a test on all of that before they can be certified by him.)  He deplored the state of affairs, with way too much needling going on based in poor training. I gathered he didn't approve of the Chan Gunn model (the one that took over Canada like a strangler fig tree).


WHAT EXACTLY IS A TRIGGER POINT, DEFINED?
He answered my question re: what exactly is being "triggered", & why are these points (so far inside the body, so supposedly responsive to a needle) called "trigger" points, with this: If they trigger a "muscle" twitch, then they are trigger points.
He doesn't differentiate between teeny muscle contracture "trigger" points and other "sore" spots, as near as I could determine: if there is a twitch to palpation, that defines it as a "trigger" point in his mind - nothing else, like for example, a crabby nerve with secondary hyperalgesia creating protective reflexive motor output from the cord (which would be palpable much more superficially). 
To me this represents a confound that has not been satisfactorily answered or eliminated. Simon Gandevia tried hard to eliminate cutaneous confound from ordinary "muscle" reflex testing and as far as I know, couldn't.

ARE THEY CAUSATION OR JUST CORRELATION?
He didn't say much when I asked him, "what if the teeny muscle contractures you study are just secondary to altered physiology that is secondary to nervous system dysfunction, and not a "cause" of anything"?
He slid past the idea that perhaps other things buried in the skin organ, contracted up by smooth muscle, secondary to physiological disturbance, might be a confound to the notion of being able to reliably palpate trigger points in striate muscle. He insisted his hands could find them except where "they are too deep" - one was left wondering if he meant the muscle was too thick, or if the cutis/subcutis was four inches thick and hard to feel through. This was unclear.
HE DISAPPROVES OF SOMASIMPLE
He thinks SomaSimple is mean to people. He has the right to entertain that opinion. Certainly SomaSimple isn't any friend to trigger point hypothesis, or ideas about treatment that are based on fascia. It's there to critique ideas, not people, but if people are too wedded to their ideas they may feel it's an inhospitable place.. that isn't SomaSimple's fault though.
I countered with this: people who are trying to think for themselves and who have become burdened by popular (but wrong, from a nervous system standpoint) opinion need a place to get gripes off their chest, and argue with (not from) "authority."

MY TAKE ON JAN DOMMERHOLT (FWIW)
Even if I still think trigger points don't exist except (*maybe*) as fleeting physiological phenomena that need no intervention of the stabbing or skewering sort, I appreciate that he has enough energy to continue researching. (He finds it effortless, apparently, whereas I found my one lone foray into it exhausting and a complete waste of my precious life that I'll never get back again.)
Maybe one day he'll manage to disprove "trigger points" as any sort of clinically important entity to his own satisfaction and to all, but meanwhile he is still invested in the hypothesis, and has funding to continue. He was clear about the model not being a scientific model yet, but only an hypothesis. Which he loves to test endlessly. And is paid to test endlessly, I gather, or else maybe gathers enough credibility equity from to make it worth his while.
Anyone who can fluently speak and write in four languages has a cortex at least four times thicker than mine and earns my respect. English as one's lone language is so limiting.  
On the other hand, there is surely something to be said for weeding out ideas that are mutually exclusive. I imagine that decluttering concepts from one's brain is at least four times harder to do when one thinks fluently in four languages.
A HUMOROUS MOMENT During the panel session he recounted a woman he treated with ultrasound, three visits to her home, with the machine not plugged in. He said, "I don't know how she got better because I didn't do ANYthing." 
I pointed out he had touched her skin.
At which point the crowd laughed. To which he replied, "Touche." About which I was pleased. (But I hope not too smug.) ........... ADDITIONAL THOUGHTS The fascia people are excited about finding "nociceptors" in fascia. One of the questions that came up during the panel discussion was an open-ended query into the significance of that. I replied that since C-fibres are everywhere (most of those polymodal) and that their main job was to assist tissue health by providing trophic factors (e.g., Substance P, CGRP, etc) to tissue to help it stay healthy, I wondered aloud if researchers were conflating "C-fibre" with "nociceptor" as if the two terms were completely interchangeable. The panel discussion closed on that note.
But back to trigger points for a moment: apparently there is a needle in existance that can suck up fluids in tissue very precisely. The procedure is a) find a trigger point b) stick it and suck up the fluids. Then, I guess, dry needle, then test again. Write up another paper noting that after dry needling, trigger points are usually gone. Interestingly the substances picked up by the needle are the usual - Substance P, CGRP, etc. However, those are just regular C-fibre products - and trophic factors! - the cell gets rid of through exocytosis, as far as I know. Everyone gets excited and thinks it automatically means they've found a "nociceptor" which usually becomes conflated with pain generator, or something. Seriously, that stuff is going to be in tissue everywhere you look, probably. Including in the skin organ. Anyway, my point is that you'll often find sand on a beach. Maybe these substances aren't anything too special - strictly correlative, not causative.
FURTHER READING (OLD BLOG POSTS)

1. Melzack & Katz, Pain. Part 19c: Implications of the Neuromatrix concept - fibromyalgia. (Aug 2013: Discussion of Fred Wolfe's current thinking while studying Melzack's latest paper.)

2. Digesting the Moose Jaw adventure: Part I (October 2012: reflections on how the medical people relate to the (ahem) hypothesis of "trigger points" from their terminally operative perspective)
3. To sum up.. (Feb 2012: A synthesis of blog posts to do with operator mentality and treatment models)
4. Letter to a biomechanically-minded therapist (July 2011: About pattern-seeking behaviour and how we have to remain vigilant about it)
5. Why I don't buy the idea that "trigger points" are in muscle (July 2011: could be all sorts of things besides muscles misbehaving)
6. Yet another "trigger point" discussion (January 2012: Lots of quotes, discussion re: pain as a brain output not a muscle input)
7. 
Trigger point model deconstruction, models in general (January 2012: A Spanish blogger retweets a paper debating the existence of trigger points (I'm an atheist myself, in case no one noticed...)
8. Fred Wolfe, trigger points, fibro (Feb 2013: a welcome surprise, a voluntary withdrawal by the guy who married tender points to a diagnosis of fibromyalgia, of this same diagnostic criteria.)

Inside these blog posts are links to papers, etc. that further discuss the issues at hand. 




Friday, March 28, 2014

Me and exercise

Imagine. 

It's fairly early in the morning. You haven't slept very well - you're a bit excited and nervous, because later that day you are going to be flying off to another city where you will be a keynote speaker at a conference for the first time in your life.

The night before, you woke up around 2am and couldn't go back to sleep - instead of tossing and turning you got up and checked your packing, made sure you had everything - passport, clothes, personal item kit, all the cables for all your devices, phone charged, camera charged, everything ready for the workshop you also had to teach later in the weekend. You went through your presentation one last time. You went back to sleep around 3:30am.

You get up around six, get some coffee, do your morning ritual of sitting down and reading email, new posts on Facebook, SomaSimple, Twitter..

The only thing you have left to do is get your presentation off your iMac and onto a stick and onto your laptop. You pat yourself on the back a little bit for being so organized.

You reach around, unplug the printer cable from the iMac port so you can plug the stick in, then plug the stick in.

At that moment, your computer goes dead. Stone cold dead.

Well, it isn't cold yet, but it's certainly dead.
And you cannot get it to turn back on. You do all the usual tricks. Check the plugin. Let it cool down.. decide, I'll deal with this after I have a shower. Have a shower. Dry your hair. Get dressed. Try to revive it. Use the trick they taught you at Apple Hospital the last time your computer went comatose - turn it on, press p, r, option and command all at the same time to make the files all sort themselves out.

Nada. The screen wakes up but stays grey: no reassuring "bonnnnnnng" sound, no apple icon, not even that little bunch of dots circling around. You wait 5 minutes. Still nada.

Uh oh. Now what?

Your mind has already hatched a plan. You know you have enough time to get the beast to the hospital before your plane leaves. Using your laptop you send a distress call to the only other human on the planet who has your presentation - the entire keynote presentation in its final state, and ask him to send it. Your email is titled "Computer disaster". 

He is there! He emails back immediately - no prob - I'll send it. And he is very soothing about all this. Incidentally he's a massage therapist.

One problem solved.

The other problem is, you've lost all the slides you were going to use for the workshop, to which he says, don't worry, just wing it and it will all be fine - same thing happened to me once, computer problems, so I winged it and the class went great.

I go get the box, get the heavy computer into it, drive an hour and a quarter to the computer hospital. I arrive about 10:45 am. I notice this time I can carry it with much less difficulty all the way from the parking lot to the store - about a ten minute walk - with way less stress and strain. Yup, having gone for regular workouts for the last two months has done me some good. No one sees me huff and puff, no one offers to carry my monster computer for me this time, like they did in November...

A tall guy named "Oak" helps me at the store. Excellent customer service. He listens. His brain ticks over. Would I like him to send me the presentation? No, it's OK - thanks, but I've got that covered.. I need you to diagnose the problem and email with me about what is wrong, how much it will cost, all that. He says, let me show you some replacement models just in case. We can do a complete data transfer onto a new unit for $49 dollars. We can give you a discount. You do a lot of photoshop so you would do better with the next grade, this one with... (bells, whistles, trunk space...). 

We agree that will be plan B - plan A will be try to fix the one I have. If possible.

I give him my external hard drive and the guy behind the counter gets all the paperwork organized, and I'm out of there and off to the airport. When I get to the airport, through security, all that, I sit down and open my email and voilá, the presentation has arrived! All will be well. As it downloads I sip my extra large mocha latte. No whipped cream, but only because Tim Horton's has run out of it. Or I would have it. I'm treating myself after having been stressed out.
......

The main point of this long tale is just to set the stage for saying that I'm convinced that this time round, I have less stress and more physical capacity. I was a bit surprised, actually. Exercise really has done me some actual good, it would seem.
In the past, when I did long bouts of exercise, some judgey part of me always stood back, arms folded, waiting to see if it could improve my mood. It never did.

This time, I went back without any expectations at all. I just wanted to stave off decrepitude, see if I would be able to fly long distances without developing ankle swelling, like after travelling home from Brazil in 2010, or a couple weeks of wheezing, like after my last trip in January.

With no expectations, the arm-folding part of me never made an appearance. 
Yet, bizarrely, I think my mood has improved. Imperceptibly.
I mean, it wasn't like I didn't feel stressed out about the death of my beloved computer, or dread the thought of lugging it, after the last time when I vowed I'd get a dolly (I ended up forgetting to buy a dolly). Both stress and dread did happen... 
What was different was that the stress seemed ... smaller, and further away, not as sensorially overwhelming as it has in the past. And the dread was much less because I felt physically stronger.

Stress/anxiety is a horrible experience. It feels so visceral. It feels like the abdominal cavity is being flushed with acid, repeatedly. It feels like everything in the thoracic cavity is being squeezed up into the throat - like there would be any extra room in there for anything extra... 

This time, my stress and anxiety felt like flutters. That's all, just flutters. Like a bunch of tiny black bats with sharp claws on their wings were flapping around inside, but not nearly as painful, and a lot more easily suppressed.
And I was favourably impressed with my improved cardiovascular stamina, carrying that monster computer all that way to the store from the parking lot. Lots of rests, but only for two seconds, and lots of scurries (carrying a heavy load on one side is easier if you scurry with small quick steps, dampening the sinusoidal gait curve all you can); no major out-of-breath-ness. 

Yup, this exercise thing might just finally have made its way into my life in a permanent way. I might just marry it, make it a lifetime commitment. 




Thursday, March 13, 2014

"50 Shades of Pain" - Lorimer Moseley quotes, compiled by Lars Avemarie in Sweden





This is just excellent. Fifty quotes by Lorimer Moseley, compiled by Lars Avemarie from a DVD produced just last year by Laree Draper, available from http://otpbooks.com for the DVD or http://movementlectures.com for download. 

It's one of those labours of love that requires the right mix of slight OCD, desire, determination, dedication, thirst for deepening into a particular topic, all that stuff. Thank you thank you thank you Lars. I've attached this to my blog so that I won't be as apt to lose it in the depths of Facebook.

I have the DVD and it's great. I was always planning to do something like what Lars has done, but have been too busy all year making cartoons in photoshop of nerves and where they go to.

If you want to sample the DVD content, Laree has posted several bits to Youtube. Here is one of them



Sunday, March 09, 2014

"Joints" that the brain might actually take quicker, closer notice of

A long time ago I wrote about "trigger points" and why I didn't think they were in muscle.

Lately I've been working hard on a bunch of images of the neurovascular array around major joints. Also I've been working on a presentation I'm scheduled to give in a few weeks at the Massage Therapist Pain Conference in Vancouver.

I decided to make a slide that depicts some of the tubing array, and joins between them, and mechanical deformation, all at the same time. 


Here is my effort: 


Green is nerve, blue is vein, red is artery. (Ignore the blue bit in the top right corner - it's part of the slide format, not part of the image.)

Bear in mind that nerves and vessels can never exist very far apart from each other. Nerves need constant access to oxygen and glucose. Bear in mind that nerves don't have (according to current thinking) any lymph drainage. If any connector vessel were to become kinked or flattened by adverse mechanical tension, for a long time, like for example, by constantly sitting and never moving, the nerve, innervated by nociceptors, is likely to complain. This would be because of a high enough threshold stimulus of the mechano-, or chemo-, type (presumably thermo- would not be an issue).  


The thing is, the physiological tubing of the body is attached all the way along. It twines and braids and twirls through the body, sliding through the same or very close "grommet holes" in stiff tissue layers to travel to the surface, into hypodermis. 

By the time it reaches the cutis/subcutis layer, the vessels are small, but still, they remain attached to nerve which although is also smaller, has fewer fascicles and is therefore more vulnerable to compression and/or deformation.

Luckily, most of us have lots of padding. Still, if your hide is always pulled sideways somehow, always the same way, by some sort of contact with a surface, the tubing inside that layer will be pulled too - maybe it won't like it. Maybe the strain will be felt quite soon, or eventually, or be broadcast out along entire branches from related spinal cord segments. Sore spots will turn up before actual pain does, probably. 




Wednesday, February 05, 2014

What Patrick Wall said about the relationship of nociception and pain

I am looking at a paper Patrick D Wall wrote with SB McMahon:


... published in Trends in Neuroscience in 1986. 

(Gee, that doesn't feel like almost 30 years ago. Time sure flies by.) 

Anyway.. 

In paragraph 1, the authors say this:


"The word nociceptor is a purely physiological term meaning fibre that responds to stimuli that damage tissue or would damage tissue if they were prolonged. The word pain is a purely psychological term defined as 'an unpleasant sensory and emotional experience associated with actual or potential tissue damage or described in terms of such damage'. What then is the relation between the physiological existence of impulses in nociceptors and the psychological response? For visceral pain, the question may not even arise, since the existence of specific visceral nociceptors is strongly doubted. But nonetheless, most textbooks of physiology and neurology imply that pain is a unique consequence of impulses in nociceptors by referring to pain fibres, pain cells and pain tracts. For instance, a recent text specializing in neuroscience states 'primary pain afferents terminate in the dorsal horn of the spinal cord', and 'the pain projection pathways are collectively called the anterolateral system'."

My bold. The reference for that is none other than Kandel, E. R. and Schwarz, J. H. (eds) (1985) Principles of Neural Science, 2nd edn, Elsevier. It's a classic. Anyone who wants to know anything about neuroscience has this big thick book on their shelf. I have the 4th edition. It is a good three inches thick and filled with wonderfulness. I don't have the latest 5th edition - something might have changed, but generally what Wall and McMahon said is true - people who write textbooks make that same sloppy error, over and over. 

In the second paragraph the authors refer to Hagbarth and Vallbo, two Swedes who developed single afferent nerve fibre recording in humans in 1968, direct comparisons they made of sensation with primary afferent discharge patterns. 

They say:

"For cutaneous sensations, the results do not support the classical view, which is still adopted by so many. Rather they demonstrate that the threshold, intensity, quality, time course and location of perceived pain is determined by central mechanisms that take into account several specifiable factors in addition to the firing of nociceptors. This article will consider these factors in some detail."

Right there is a good reason to do human primate social grooming - persuade the brain at the other end of those neurons to change its mind about how the world "feels" to it. But I digress. For more about microneurography, you can check out these cited references: Hagbarth, K. E. and Vallbo, A. B. (1968) Exp. Neurol. 22, 674-694, and Vallbo, A. B. and Hagbarth, K. E. (1968) Exp. Neurol. 21, 270-289. 


Wall and McMahon go on about very specific advanced (in the day) microneurography technique "in which they pass current through their recording electrodes and claim to stimulate the same fibre that they had been recording from, and that fibre only." And they cite:  
Schady, W. J. L., Torebjörk, H. E. and Ochoa, J. L. (1983) Brain Res. 277, 249-261 5
Torebjörk, H. E. and Ochoa, J. L. (1980) Acta Physiol. Scand. 110, 445--447 6
Vallbo, A. B. (1976)Acta Physiol. Scand. 97, 66-74 7
Vallbo, A. B. (1981)Brain Res. 215,359-363 8
Vallbo, A. B., Olsson, K. A., Westberg, K-G. and Clark, F. J. (1984) Brain 107,727-740
They continue describing how this approach has been used for a range of tactile cutaneous afferents, how this has led the researchers to conclude that "activation of a single afferent nerve fibre gives rise to a sensation that corresponds to the properties of the receptive field of the fibre." That "these findings endorse the concept that the quality of sensation is coded in specific sensory systems", that "they provide novel evidence that sensory quality, magnitude and localization can be exquisitely resolved at cognitive levels on the basis of input initiated in a single mechanoreceptor unit." The reference provided is Ochoa, J. and Torebjörk, E. (1983) J. Physiol. (London) 342, 633-654.

Apparently Wall and McMahon must have protested the neatness and tidiness and conclusiveness of all this: the arguments they mounted are "fully discussed elsewhere" in Wall, P. D. and McMahon, S. B. (1985)Pain 21, 209-229.

They continue:
"Here we wish only to point out that there are objections to these conclusions and to correct any impression that the work supports the notion that pain is the equivalent of afferent nociceptor discharge. In fact, even the microneuronographers themselves do not make the same claims for pain as they do for touch, although it is easy to see how their general conclusions regarding cutaneous sensibility might be taken to apply to pain."

A bunch of technical stuff follows: tungsten electrodes, who was who and who did what. Comments are made about how the size of the electrode is the same as that of the axon being tested. They remark, "The most likely explanation of these single unit recordings is that the presence of the electrode and its manipulation induces a pressure block of the majority of the nearby fibres allowing only one or a few axons to conduct impulses into the region of the recording tip."

Details reside in  
Hallin, R. G. and Torebjörk, H. E. (1970) Acta Soc. Med. Ups. 75, 277-281
Torebjörk, H. E. and Hallin, R. G. (1970) Acta Soc. Med. Ups. 75, 81-84
Van Hees, H. and Gybels, J. M. (1972) Brain Res. 48, 397-400

Then the discussion turns to A deltas and Cs:
Hallin, R. G. and Torebjörk, H. E. (1970) Acta Soc. Med. Ups. 75, 277-281
Torebjörk, H. E. and Hallin, R. G. (1970) Acta Soc. Med. Ups. 75, 81-84
Van Hees, H. and Gybels, J. M. (1972)Brain Res. 48, 397-400
Gybels, J., Handwerker, H. O. and van Hees, J. (1979) J. PhysioL (London) 292, 193-206
They continue: 
"It might be expected that the onset of firing of one of these types of fibre would invariably coincide with the onset of pain, but this has not been observed. Both groups of fibres begin to respond to pressure or chemicals or heat at stimulus intensities well below those that evoke pain. To take C fibres responding to heat as an example, most fibres begin responding at 41°C while the pain threshold can be as high as 49°C. In this study, the authors conclude that central spatial summation from many nociceptors is necessary before pain is sensed (Torebjörk, H. E., La Motte, R.H. and Robinson, C. J. (1984) J. Neurophysiol. 51, 325-339). Another group show that 'subjective ratings give a better estimation of stimulus size than did the discharge rates of the individual C fibres' (Gybels, J., Handwerker, H. O. and van Hees, J. (1979) J. PhysioL (London) 292, 193-206).
It is apparent that the ability to establish a threshold and to estimate intensity is not determined by the properties of single peripheral fibres or even types of peripheral fibre. Rather the periphery feeds information that is then interpreted in terms of threshold and intensity by central structures."

See what they did? They spotted an inconsistency in the work itself, an oversight, a contradiction between what was actually stated, and how most people went on to blithely interpret it. Then they pointed it out, in writing.

They go on about that for awhile longer, point out how subjects can't tell the difference between hot punctate stimulus or just punctate pressure, how much of a difference there is in pain threshold: "The C fibre firing rate when the stimulus becomes painful is 0.5 Hz for the heat stimulus and over 10 Hz for the pressure stimulus." How the difference is predicted by gate control theory, explained by the fact that pressure stimulus activates both high and low threshold fibres, that low threshold fibres exert inhibition over central excitation produced by small afferents (Melzack, R. and Wall, P. D. (1962)Brain 85, 331-356). How a larger afferent barrage is required in small fibres to produce the same central effect if large fibres are being stimulated at the same time. How this reflects the way the CNS responds to combinations of inputs from many different fibre types. This sort of reflection continues for a good length of time in the paper with minute detail about pain thresholds, size of area being stimulated, what size probe results in what sort of perceived sensation. 
"This evidence shows that the CNS is analysing modality and intensity not only on the basis of firing frequency in particular afferents but also by taking into account the spatial gradient of the stimulus. This contradicts the classical view that modality is determined by the activation of modality-labelled specific fibres that end in local skin spots. Spot-like variations in sensitivity exist but they cannot be attributed to the local presence of special nerve fibres for the following reasons. The spots rapidly move, appear and coalesce. They are not associated with particular types of ending. There are far more endings than spots. The size of the spot depends on the size of the stimulus (Melzack, R. and Wall, P. D. (1962) Brain 85, 331-356; Boring, E.G.(1942) Sensation and Perception in the History of Experimental Psychology, Appleton-Century-Crofts; Johansson, R. S. and Vallbo, A. B. (1979) J. Physiol. (London) 286, 283-300; Johansson, R. S. and Vallbo, A. B. (1976) in Sensory Functions of the Skin in Primates (Zotterman, Y ., ed.), pp. 171-184, Pergamon Press).
"These facts require that the central processing of the afferent barrage take into account which groups of fibres are responding, what is their relative frequency of discharge, and what is the spatial gradient of responding fibres."
Then more technical detail about A deltas and Cs.
Then,  "It is evident that the time course of sensation is determined by central factors other than the arrival of the afferent barrage (Vallbo, A. B. and Johansson, R. S. (1976) in Sensory Functions of the Skin in Primates (Zotterman, Y., ed.), pp. 185-199, Pergamon Press)."

This is true. So very true. Which is why we human primate social groomers need to be careful with our handling. 

They go on about what sort of subjects volunteer for such experiments, and comment that "It is not surprising that the slings and arrows of of the real world produce pain by mechanisms that require more factors for their explanation than the firing of a specific type of afferent. At one extreme, 90% of patients with brachial root avulsions suffer severe pain in the absence of afferents let alone impulses in afferents. At the other extreme, 40% of patients admitted to a civil accident hospital suffered no pain at the time of their injury in spite of being fully aware that they were severely injured. Between these extremes, pain is perceived in terms of injury in the context of the afferent barrage in nociceptors and of other afferents and of analytic processes in the brain."

My mind drifts back to Kevin Ware, who swore he felt no pain when his leg broke and he collapsed on the basketball court last spring, his tibia sticking out a good three inches beyond the skin it tore through, leg bent at a crazy angle, foot dangling helplessly; I am reminded of the guy who suffered acute agony in a construction injury, wouldn't let anyone touch him or the boot from which protruded a large spike, until he was give a big dose of pain meds, but when the boot was removed, it turned out the spike had only pierced the boot, not the foot. 

Wall and McMahon conclude,
"The awareness of touch by itself may be a neutral event without implicit meaning. The labelling of nociceptors as pain fibres was not an admirable simplification but an unfortunate trivialization. The writers of textbooks will continue to purvey trivialization under the guise of simplification. The experimental results show that the final analysis that produces the perception of pain is not monopolized by the peripheral receptor properties of nociceptors. The response of nociceptors is one of the factors incorporated into the central analytic mechanisms that can generate many perceptual syndromes including pain."
My bolds. 
Life grinds on. 
The 'unfortunate trivialization' continues. 


Patrick Wall
1925-2001




By Sigurd Mikkelsen, Norwegian PT

FURTHER READING:
Mechanisms of Pain, Chapter 2 in Recognition and Alleviation of Pain in Laboratory Animals. Very clear straightforward elucidation of the difference between pain and nociception.