Saturday, July 20, 2019

Treating cutaneous nerves and reducing muscle hypertonicity: What's the connection?

This question was posed to me in the DNM group on Facebook a few days ago. It's worth a blog post, I'm sure, because way too many practitioners out there in the big wide world still think they must have magic hands or something, and their instructors never explained to them that they don't.

Here was the question: 




I will reproduce my answer and alter it slightly so that it contains (I hope..) more clarity and expand it with links.

The whole physical basis of DNM is neurodynamics, as treatment described by Butler and Shacklock (although they only discussed long deep nerves), plus neurodynamics, as normal nerve movement as described by Lundborg in his nook, Nerve Injury and Repair, 1988

TWO DEFINITIONS FOR NEURODYNAMICS
It's important to realize there are two definitions for "neurodynamics":
1. the "normal" "physiological" movement of nerves through neural tunnels, with ordinary active movement as so well-described by Lundborg in his book, Nerve Injury and Repair, from 1988, with all its gorgeous, rich illustrations
2. the "applied" "treatment" kind, defined by Michael Shacklock in his pivotal 1995 paper, "Neurodynamics" (Type the word into the box and click on the teeny box beneath to read the full paper, or download here instead.)  



PERIPHERAL NERVES ARE NAMED IN FAVOUR OF THEIR MOTOR FUNCTION
(cont.)
... I like to think of nerves as information highways inside tubes throughout the body - 72 kilometers of them. The cutaneous nerves are fascicles branching away from the deeper named nerves, as are the motor branches, even though the motor branches are not usually given their own names the way cutaneous branches are. If you think of a highway in normal driving life, let's call it Highway 315, it would be like exit 42 goes to a muscle; the branch to the muscle contains motor neurons, but the name of that branch isn't separate from the name of the nerve itself (which is odd in my view, but oh well..). So we say, Highway 315 innervates the blahblah muscle, or even several muscles.
The nomenclature of peripheral nerves has always been biased in favour of the motor function of the nervous system. Even though ALL the main peripheral nerves are "mixed" (both sensory and motor), only cutaneous nerve branches are selected out for being "different" enough to get specific names. Motor branches of peripheral nerves do not.
From one perspective, this makes cutaneous nerves easier to learn from an anatomy text.
From another perspective, it can present a cognitive chasm - how does handling affect motor output? Pain output?
For manual therapists, it means that to understand how our handling affects nerves/nervous system we have to delve a lot deeper into the body of knowledge and are forced to be more rational


From this wonderful youtube video with Rafe Kelley and John Vervaeke, about minute 51

Back to the answer to the question:

But then we have exit 73. As soon as you take that exit, you find yourself on a "new" highway with a "new" name, maybe "Lake Road" or something. It's a different branch of the same big nerve, but it goes away from muscle instead of into it, doesn't contain any motor neurons, only autonomic motor neurons and sensory neurons, and it goes to skin. 

I want to rename this highway branch, "Vista View Road."
It doesn't go to a lake, it goes out to skin, and skin is open to the world.
To the environment.
These nerves pick up on everything out there.
Ambient temperature, breezes, contact with the planet through the soles of the feet.
Furthermore one can argue that special senses also have "skin" or at least, specialized membrane containing receptive neurons for picking up on light levels, different noises, different scents in the air depending on what season we are in, humidity levels, all sorts of inputs that are mainly subliminal and are handled efficiently by very old predictive processing systems in our central nervous system.
But I digress.
And I got carried away with the sensory function in cutaneous nerves. Lest we forget, they also contain numerous autonomic neurons, which are sympathetic, which are motor, and which regulate all the enormous vascular function of the skin organ, which contains 10 times more blood supply than needed for its own metabolic function, acting as a reservoir for emergencies and a thermodynamic regulatory organ for keeping body temperature within the narrow optimal homeostatic range necessary for life processes in mammals (of which we are a kind). I learned all this from reading Gray's Anatomy.
And I digressed again.
Back to the original answer: 


With me so far? 
Now, imagine that you can put your hand on "Lake Road", and physically move it, because it's embedded right into the underneath side of the skin! It's got its own fascicle inside the tubular Highway 315! When you move the skin, you move that fascicle (physically) all the way up Highway 315 (or at least a long way up it), and even, in fact (sensorially), all the way up to the brain. 

This is an important manual therapy concept to get: imagine pulling a string through a tube.
Imagine the tube (which is the peripheral nerve itself, containing lots of strings) goes all the way to the spinal cord.
Imagine the string you pull is easy enough to pull because it embeds right into the skin (organ), which you can "KNOW" (for a fact!) that you can get your hand directly on and move.
Plus, you are activating all kinds of computational low-threshold mechanoreceptors right at the skin organ surface. Of course the brain will know that someone is touching its organism, and how. 




ASCENDING PATHWAYS

This might be where Descartes got off track thinking there were specific "pain" neurons going to the brain. The thick heavily myelinated low-threshold A-beta mechanoreceptive neurons in skin certainly do - they go up the dorsal columns of the spinal cord to dorsal column nuclei in the medulla, synapse there, cross over, synapse again in the thalamus, and end up in the primary somatosensory cortex with high fidelity.
Nociceptive-capable, high-threshold neurons end in the dorsal horn of the spinal cord.
Well, unless they are A-delta nociceptive neurons, which are a bit thicker and faster with a bit more myelination, seem to have a lot more sensory-discriminative capacity, and are usually well and quickly inhibited.
See link.
And I digressed yet again.


(Furthermore, "Lake Road" has multiple turnoffs that go straight to the skin organ's surface, called rami, each inside its own little tube called a skin ligament!)
Yes. I took pictures of them.
With special permission.
Specifically, these are cutaneous rami of the lateral cutaneous nerve of the forearm (highlighted with a black felt marker).
I did this dissection in 2007 at UBC.
See Nash 2004 for a description of skin ligaments. 




ANASTOMOSING


Anatomically things are a lot more complex of course, fascicles anatomose and diverge right inside the nerve, and nerves themselves diverge and anastomose inside the plexuses from which they differentiate, etc.. PLUS all these fascicles have blood vessels going into them from accompanying arteries and out of them into accompanying veins and all this attached vasculature will ALSO be moved a little.

To see images of all this anastomosing business, plus neurodynamic elongation of nerve fascicles, go here

AND (we hope) moving said vasculature can mechanically affect, for the better (we hope!), said vascular function within the nerve (intraneural blood flow). Particularly if there is local pain, which MAY be a tunnel issue secondary to insufficient drainage/consequent intraneural engorgement/entrapment. 
But be all that as it may, Lundborg showed that fascicles can slide a bit to afford nerve elongation (sort of like a telescope can elongate by its inner parts sliding outward). 
And Butler and Shacklock (and whoever came along before they did) took these ideas and pain science at the time (late 80's, early 90's) and developed nerve sliding etc. as a treatment approach. Neither one of them worried much about cutaneous nerves, however, which is where I picked up the ideas and have included neurodynamics in treatment approaches to skin, i.e., moving of cutaneous nerves and their multiple rami, 1.) not just trying to have a sensory influence on the brain via skin receptors (although that is responsible for a lot of treatment effect), 2.) completely eliminating all irrelevant operative erroneous superfluous assumptions (still floating around like stinking bloated corpses in the river of ideas... 🙄👎 ) imagining we could possibly in a billion years affect mesodermally derived tissue (e.g., the myo, or the fascia..) directly
Then after some time had elapsed, I realized I still had not addressed the actual question:

TOP-DOWN, BOTTOM-UP

Gad, I wrote all that stuff but didn't get around to answering the question did I? >>> "I have not found a concrete explanation as to how affecting the cutaneous nerves reduces hypertension in a muscle. So, what is the mechanism?"The only mechanism that has a ton of research to back it up is "non-specific effects", more specifically, top-down "descending modulation" by the brain, of the spinal cord. The brain's usual order of business is to inhibit gross spinal cord reflexive behavior. It's like the spinal cord thinks its job is to make everything BIG and the brain's job is to say, now now, not so big, and not right now. Remember the spinal cord can elicit withdrawal reflex in response to nociceptive input BEFORE the brain even registers a problem (i.e., be VERY protective. Maybe even over-protective.) (Plus the spinal cord came along earlier than the rest of the CNS so it tries to play the seniority card I suspect.)
Anyway, 50 years after Melzack and Wall's paper on gate control theory, a paper came out in 2015 that afforded it some direct evidence. (Foster et al 2015, see link) so there is now a shred of support for a bit of bottom-up inhibition of nociception as well. 
Yay. 

The Foster et al. paper is here

SPINAL CORD WITHDRAWAL REFLEX

I added a bit later on in the thread that is my hunch (can't find any definitive reference for it yet) about why muscle hypertonicity occurs, even though it irritates the heck out of peripheral nerves that may be getting squeezed on in the process. 




From this thread
........................

I hope this rounds out the discussion a bit more.

............

1. Shacklock, M. (1995). Neurodynamics. Physiotherapy, 81(1), 9–16. doi:10.1016/s0031-9406(05)67024-1
2. Neurodynamic Solutions 20th Anniversary Newsletter, "Nerve movement in 2015 - 20th Anniversary of neurodynamics in physical and manual therapy." Contains nerve movement video showing proof of concept and download link to full Neurodynamics paper cited above.
3. 
https://thebrain.mcgill.ca/flash/d/d_03/d_03_cl/d_03_cl_dou/d_03_cl_dou.html
4. Nash, L. G., Phillips, M. N., Nicholson, H., Barnett, R., & Zhang, M. (2004). Skin ligaments: Clinical Anatomy, 17(4), 287–293.doi:10.1002/ca.10203 
5. 
Foster, E., Wildner, H., Tudeau, L., Haueter, S., Ralvenius, W. T., Jegen, M., … Zeilhofer, H. U. (2015). Targeted Ablation, Silencing, and Activation Establish Glycinergic Dorsal Horn Neurons as Key Components of a Spinal Gate for Pain and Itch. Neuron, 85(6), 1289–1304.doi:10.1016/j.neuron.2015.02.028

Wednesday, June 19, 2019

Scroll of Truth

I don't know who made this cartoon but whoever it is, THANK YOU!


So true. So very true.
Haha at all the spinal HVLA manipulators out there. 
The majority of patients having manual therapy for back or neck pain report adverse events. 

Meanwhile, this might be what manual therapy is REALLY all about..
The interoceptive turn
"The science of how we sense ourselves from within, including our bodily states, is creating a radical picture of selfhood."

Is it ever.

This new paper, just out, proposes that the effects of massage on depression may be all about helping this inner sense of self to change. I would argue this is not limited to only massage but pertains to all slow, kind, interactive, intelligent manual therapy. 

Wednesday, June 12, 2019

What lurks at the bottom of the chasm?



When Dave Nicholl's published this particular blog post, I rejoiced.
Excerpt:

The model does not explain the real world. If it did, it would reside in the real world and one wouldn’t have to study to become a trained health professional to understand and apply it. Biomedicine then, at its worst, sits at odds with the people it is meant to serve; looking, again, rather like a spoilt (white, male), only child of very rich parents, in a room full of people whose lives are very different indeed.

But, then this piece caught my eye, and I rejoiced even more. Philosophical bias is unavoidable by science.
Excerpt: 

One school of thought viewed the new plant as a conventional hybrid and argued that, in most cases, one can deduce the safety of the new plant from knowledge of the safety of its parental GM plants. This means thinking about complexity as being various combinations of unchanging parts. The other school, however, argued that one cannot deduce the safety of the new plant from the safety of the parental GM plants. Here, complexity is thought of as an emergent matter where parts lose their properties and identity in the process of interaction.
Imagine: one idea of complexity is all about nouns (like plant parts) moving around as though they had autonomy or something, and another idea of complexity is that of emergence, that the plant parts are moved by their environment and relationships, interactively, and it's all contextual. 

Then I really rejoiced when I noticed this, today: The Burning Question





Trying to find anything specific in therapy of various kinds performed on alive awake cognizant individuals with pain reminds me of Tim Conway skits on the Carol Burnett show, ones in which he would play an old guy trying to open a door but banging it shut with his head, over and over.  


Why did I rejoice?
Because the mystery is becoming more clear. Not what can clear up the mystery.
So is the chasm.
And what is at the bottom of it. 


1.  https://criticalphysio.net/2019/06/05/critique-of-the-biomedical-model-2/
2. Philosophy of biology: Philosophical bias is the one bias that science cannot avoid.
3. 
https://www.facebook.com/photo.php?fbid=10161759445590183&set=gm.2231921840431689&type=3&theater

Teacher upgrade



When I got back from teaching DNM in Montreal I was exhausted as usual, but I feel like I can see a new vista in my internal landscape. I feel like I was enclosed in my own tunnel of ignorance about teaching for all this time, and didn't even realize I was in one, was dimly aware though how I was out there in the world teaching away with absolutely no teaching skills or tricks, just blurting out foundational stuff and showing a lot of powerpoint slides.
Yannick Wenger from France showed me a few new tricks - like how to draw more out of the minds of the people in the class by asking them what they remembered from the previous day, and making sure their purpose for being there was being fulfilled adequately. The French have been onto all this stuff ever since their revolution, it seems.
Thank you, Yannick.

Theory U
Social constructivism
Universal method of education (Jacotot)


What the class remembered. 

Saturday, April 20, 2019

"People need to feel HEARD, not HURT" (Lissanthea Taylor)




Is it really April? Already? 

("Time keeps on slipping, slipping, slipping, into the future..")

.............


So far this year has been technically prolific.
Technology is all around, and people who know how to use it, and want to use it.


1. An interview Lissanthea Taylor did with me at the San Diego Pain Summit in February. She came up with the great tagline, "People need/want to feel HEARD, not HURT".  PainChats is her brainchild, her attempt to get accurate information about pain out into the world and into the lives of as much of the public as possible, to change attitudes toward pain and the culture itself. She is part of Pain Revolution, an annual outreach bike tour in Australia that brings updated pain information to rural communities.

Know Your Nervous System And How It Causes Pain



2. A trip to Australia, and two more workshops done. Antony Lo filmed the first one in Noosa. All his filming will make it to Embodia, an online education resource for physios, affiliated with CPA, and the brainchild of Maggie Bergeron. It will be whittled down (a lot!) and (we hope) produced into an educational video.
He also interviewed me for his podcast, for PhysioDetective.



Antony Lo and his PhysioDetectivePodcast interview, March 2019




3. Nick Efthimiou hosted my workshop in Melbourne, and wrote up an overview of the time we spent together for his blog at Integrated Osteopathy.


10 Things I Learnt From 10 Days With Diane Jacobs

Previous to the workshop, he arranged for Stephen King of 21st Century Physio Podcast to interview me - Episode 017 - Diane Jacobs Brings You Into the 21st Century


Stephen King interviewing me at home, from Australia


..............................


Now it's time to go to Paris and teach the workshop prepared and hosted by Louise Tremblay. It will be fun to hang out with Louise there - she is Francophone,  knows the city well.
The rest of 2019 workshops are all on this continent - relief from jet lag until 2020.


...............................

















Thursday, November 29, 2018

The importance of STORIES

So many threads in my head coming together today.
Convergences!
Just one of those days I guess...
They are rare enough and welcome when they arrive.
Days when I feel inspired.

STORIES! 

1. An interview Mark Kargela has just done with Peter O'Sullivan and Joletta Belton (about an hour long on Facebook). Peter describes how important the patient's story is - the narrative they will offer (if you just ask them to tell it to you!) will contain all the bits needed for them to move on. Joletta concurs.
He is trying to develop a way of teaching clinical interaction in his work as an instructor, continue having a clinical practice, and how something had to give so it was the traveling/teaching workshops around the world, for a year*.  If anyone can manage to do it in a way the profession itself will notice and adapt, it will be him!! Go Peter go!!
In it, Mark mentions manual therapy that is "supportive, not corrective" and comes across that way to the patient. Very important, if you are out there in the world doing manual therapy and trying to cross the chasm from being operative toward being interactive. If you are trying to deal with a predictive brain, you have to set it up so it thinks recovery was its own idea.
(Here is a blogpost I did about Peter's workshop on Cognitive Functional Therapy at the San Diego Pain Summit a couple years ago.)

2. Monic Noij's wonderfully evocative blogpost, her story about how it felt/feels to do just that, cross the chasm, deal with cognitive dissonance, change the way you were taught how to 'be' (i.e., operative) into something else almost entirely (less operative), and the feeling of the ground disappearing out from under you as you step through the necessary cognitive changes.
It reads like a real adventure story fraught with danger, disappointments, eventual survival and after that, who knows?
Just read it:
What's on the path ahead? Adventures in crossing the chasm.
(Her blogposts are all very well-written - read them all.)

3. A wonderful description of the biopsychosocial model by Julie Tudor
The entire post is good, but this part is my fave, her story about how BPS model is like a lava lamp:

"We all see BPS or SPB (or PBS, for all I know) as being represented by this neat little Venn diagram of overlapping circles, each of the same size and importance. This is a fantasy, created by people who were still seeped in the priority of the biomedical approach. In reality, there are NO clear delineations.
NONE. ZIP. ZERO. ZILCH.
Those borders are smeared and loopy and smudged inextricably. It looks more like a triple colored blob inside a lava lamp, entangled in a constant ebb and flow, with little bubbles of each breaking off and dancing in and out of each other, while larger clumps may loll about at the base or flow up to engulf their errant offspring. One blob may appear bigger than the others, and then collapse into the weight of another color. These primary colors may also blend with those, and create a rainbow effect with no discernible beginning or end (...and no pot of gold, either)."
I really like the metaphor of the model described by her as being an impossible-to-ignore-or-manipulate verb, not a static, easy-to-manipulate-and-make-assumptions-about-or-ignore-entirely noun.

 4. A glowing book review by Harriet Hall of the book by James Alcock, Belief: What It Means to Believe and Why Our Convictions Are So Compelling.
For sure, this resonates with the whole cognitive dissonance experience (see point 3. above) that lays waste to any cherished beliefs we may have previously clung to as practitioners. It sure does suck bigtime, and hurts. You have to figure out how to grieve your own ego, then let it go.
The part that jumped out at me most in this book review however was Harriet Hall's account of the author's description, his story of three types of healing: 

"Belief and healing:  Feeling better after a treatment doesn’t necessarily mean we actually are better. Suggestion is powerful, healing rituals are persuasive. He covers Mesmer’s “animal magnetism,” placebo effects, sham surgeries, learned responses, expectancy effects, conditioning, social learning, and theological placebos. He says there are three types of healing: natural healing (the body heals itself), technological healing (drugs, surgery) and interpersonal healing that depends on context and personal interactions and that leads to improvements in illness but not in disease."

I had never thought about healing that way. It makes sense though - the third category is what most of us are in, as allied health professionals.
I hope we are all there for each other that way.

5. At last, this: The Difference Between Fixing and Healing, the transcript of an interview with Rachel Naomi Remen, a medical doctor and author of Kitchen Table Wisdom and My Grandfather's Blessings. She discusses how important the stories are - it's through the stories that people can find their way. Find their way out of pain (Peter O'Sullivan and Joletta Belton). Find their way across chasms (Monica Noij). Find their way to understanding something complex and abstract (Julie Tudor).
Her own story is that her mystical grandfather, a rabbi, told her a creation story when she was four years old. It was (roughly paraphrased) about how the light of the world broke up into many pieces, how humans are here to put the light back together, how each human has a little bit of that original light to bring to the effort. When she was 15 she was diagnosed with Chrohn's Disease, and her mother reminded her of the story her grandfather had told her when she was a little girl. It strengthened her. She went on to become a medical doctor, which is a chasm of its own kind, and now she walks (my take on this) with one foot on each side of that chasm, being both a medical doctor and a "healer"- counselor of gravely ill patients - on the other. Plus a fabulous writer. She acknowledges the operative side of medicine and does a great job or highlighting the interactive side. Of the chasm.
Really, not to diminish anyone's journey across their own chasm, because it will always feel huge and insurmountable, but the size of the chasm she has successfully navigated with so many gifts to bring makes me feel like the one I crossed a few decades back (then had to find language to describe) was more the size of a scratch with a twig in the sand at the beach.


...................................

REFERENCES

1. Mark Kargela's interview with Peter O'Sullivan and Joletta Belton (2018)
2. What is the operator model? What is the interactor model? (2011)
3. 
Ownership and agency in a predictive brain, implications for manual therapy (2017)
4. Peter O'Sullivan San Diego Pain Summit 2017 blogpost (2017)
5. Monica Noij's blogpost on crossing the chasm (2018)
6. Julie Tudor's essay on the biopsychosocial model (2018)
7. Harriet Hall's book review of James Alcock's book on belief (2018)
8. The interview transcript with Rachel Naomi Remen (2018)

FOOTNOTE

(*I am thinking about giving up traveling too - maybe just for a year, maybe longer - it really grinds down one's gears, physiologically. It gets to the point where it takes so long to recover from the traveling that one's entire life becomes scheduling recovery time between workshops, and feeling quite out of it for days. That is no way to waste one's physiological capital let along build upon whatever one managed to glean by way of being stimulated in a new context. Just no way to consolidate any thoughts or themes - too much recovering to do, too tiring. Sucks away whatever tiny shred of creativity one may possess.)

Wednesday, October 17, 2018

Ongaro and Kaptchuk 2.1



This blogpost deals with the first reference in the introduction of the paper I'm currently reading and absorbing (Ongaro, Giulio, Kaptchuk, Ted J., 2018, Symptom perception, placebo effects, and the Bayesian brain. PAIN, Aug 6, 2018. (To read the full paper, click on "Article as pdf").

The references are cited in the last sentence of the intro:

"It expands on recent high-quality empirical work on predictive processing (1,7,19,24) and outlines, more broadly, how Bayesian models offer an altogether different picture of how the brain perceives symptoms and relief."

The first reference is 
Anchisi D, Zanon MA. Bayesian perspective on sensory and cognitive integration in pain perception and placebo analgesia. PLoS One 2015. First, the authors
Davide Anchisi and Marco Zanon are both in Italy. Italy is a hotbed of placebo research (Fabrizio Benedetti* is in Italy as well). Both authors are at Department of Medical and Biological Sciences, Università degli Studi di Udine, Udine, Italy, according to PubMed, although Zanon may be in Bologna now.
Here is a 
list of publications by Anchisi;  Anchisi is an MD and PhD.Here is a list of publications by Zanon;  Zanon is a post-doc research fellow with the psychology department. 



Excerpts 

1. "How can an inert treatment cause a response?"
This is the first sentence. Good question. My follow-up question is, who decided that any given treatment was "inert"? What were their criteria? They certainly left out a lot of info or maybe their info was incomplete. Right? An awake alert human brain is always going to respond to context of said treatment, so nothing can ever truly be "inert." But I digress.  


2. "... living organisms and their perceptive systems deal with uncertainty and face transposed conditional probability problems: they have to infer the features of activating stimuli (related to the state of the world) from nervous signals elicited by those stimuli, and come to a reliable perception (i.e., make an effective decision) in spite of the noisy and incomplete information that sensory signals provide about the world."
Yup, that's pretty much what the nervous system is doing from the moment it switches itself on as an embryo to the day it dies.


3. ".. experimental and theoretical work showed that perception is a multisensory task and support the hypothesis that, in perception, different pieces of information are near optimally combined in a Bayesian way."
Note to self: learn whatever I can grok about "Bayesian." This link states: 


"Bayesian statistics is a system for describing epistemological uncertainty using the mathematical language of probability. In the 'Bayesian paradigm,' degrees of belief in states of nature are specified; these are non-negative, and the total belief in all states of nature is fixed to be one. Bayesian statistical methods start with existing 'prior' beliefs, and update these using data to give 'posterior' beliefs, which may be used as the basis for inferential decisions."
Apparently there was a guy in 1763, Thomas Bayes, who came up with this.  

4. "
In this study we focused on the placebo effect because it is one of the best examples of experimentally controllable modulation of pain experience, and has been extensively investigated in recent decades." OK...

5. "Our aim was to develop a Bayesian framework which could describe and explain pain perception and its modulation....As we argue here, the nociceptive signals are not the only source of information used to compute the inference: past experience and cognitive information also play a role."
As Melzack's Neuromatrix framework states.

6. "
A total of 55 healthy human volunteers (mean age ± s.d.: 21.40 ± 1.03; 29 females) were recruited by advertising at the University of Udine (Italy) and randomly divided into two groups: Experiment 1 (n = 24); and Experiment 2 (n = 31)." And then they "conditioned" the subjects (gave a bunch of twentyish-year-olds the opportunity to organize their expectations), and applied TENS.

7. "
The main findings of this study concern not only the placebo effect but a wider range of effects also due to past experience." I wonder what results would look like if the subjects were in their 60's or 70's? Just a thought.

8. "
The Bayesian decision model we developed comprises three key elements: the prior probability, which conveys previous experiences and expectancy (e.g. through information derived from the context); the likelihood function, which implements the sensory inputs and also information from multiple sources (whether sensory, cognitive or psychological); and the decision process, which eventually determines if and to what extent pain is perceived."

9. "
The model we developed shows how the placebo effect results from the evaluation and integration of nociceptive stimuli with context information, and how the relevance of the context (through expectation/conditioning) comes, at least in part, from past experience. The process of information integration would be at the very base of pain perception, and would lead to the placebo effect and to other phenomena such as those predicted by the fBD model.

Overall, our findings support the hypothesis that pain perception can be described according to the rules of Bayesian probabilistic reasoning."

.....................................................................................
Ongaro and Kaptchuk 1: Intro 
Ongaro and Kaptchuk 2: Intro

*I spent a great deal of time with Benedetti's book, The Patient's Brain, read it cover to cover, made lots of notes; I also had the pleasure of hearing him speak about his work at the San Diego Pain Summit in 2016.

























Monday, October 15, 2018

Ongaro and Kaptchuk 2: Introduction

See Ongaro, Giulio, Kaptchuk, Ted J., 2018, Symptom perception, placebo effects, and the Bayesian brain. PAIN, Aug 6, 2018. (To read the full paper, click on "Article as pdf") This is all the introduction.


What I like about it (so far) and the predictive processing model for looking at the brain is that it treats the brain as a verb, not a noun.

First line of the introduction:

"The standard and ideal biomedical model of symptom perception treats the brain largely as a passive stimulus-driven organ."

Yup, that's the Cartesian way of looking at another human being.
Lest we forget, "being" is a verb. Or at least a gerund.

Second sentence:

"It embraces the notion that the brain absorbs sensory signals from the body and converts them, directly, into conscious experience."

It may do that before it has any experience to also draw on, e.g., within the first few months of life..

Third sentence:

"Accordingly, biomedicine operates under the assumption that symptoms are the direct consequences of physiological dysfunction and improvement is the direct consequence of the restoration of bodily function."

Yup, very convenient. Also useful. Has been successful to a large extent.
Also very Cartesian. Easy to blame the patient if their particular "pain" doesn't fit into the model, i.e., "the patient must be crazy"

Fourth sentence:

"Despite its success, the biomedical model has failed to provide an adequate account of 2 well-demonstrated phenomena in medicine: (1) the experience of symptoms without pathophysiological disruption, and (2) the experience of relief after the administration of placebo treatments."

Yup. E.g., (1) phantom limb pain, and (2) resolving it by stabbing a screwdriver into the artificial limb (one of the stories in Painful Yarns by Lorimer Moseley).

Fifth sentence:

"This topical review advances the idea that “predictive processing,” a Bayesian approach to perception that is rapidly taking hold in neuroscience, significantly helps accommodating these 2 phenomena."

At last!!

Sixth sentence:

"It expands on recent high-quality empirical work on predictive processing (1,7,19,24) and outlines, more broadly, how Bayesian models offer an altogether different picture of how the brain perceives symptoms and relief."

Ah yes... inevitably, there is always going to be a ton of side reading to do. Not that I mind side reading when motivated! I see we will have to go to blogposts 2.1 - 2.4.

7. Büchel C, Geuter S, Sprenger C, Eippert F. Placebo analgesia: a predictive coding perspective. Neuron 2014;81:1223–39.
19. Grahl A, Onat S, Büchel C.The periaqueductal gray and Bayesian integration in placebo analgesia. Elife 2018;7:e32930.
24. Kaptchuk TJ. Open-label placebos: reflections on a research agenda. Perspect Biol Med 2018;61:311–34.

.......................... Other blogposts in this series