Adventures in the Jungle of the Neuro-Myofascial Net

First published in ROLF LINES, May 1996
by Robert Schleip


Fascia and the brain

It is now years ago that I did some experiments with bodies under anesthesia (as had Milton Trager and Rolfer Bob Hall years before). The results lead me to the conclusion that our classical 'Gel to Sol Theory' was either not accurate or sufficient as a model to explain the immediate tissue response to manual pressure. Obviously the nervous system plays an important role in the maintenance of structure as well as in our myofascial work - and should therefore be included in our theoretical models. Working on a fresh piece of chicken meat or on an anaesthetized body is not Rolfing; something very vital is missing, something which I keep associating with the term 'aliveness', which seems to have to do with active nervous system self-regulation responses ... and which has fascinated me ever since.

Reading an article .... and going to the phone

Nov.94: an article in the German edition of National Geographer gets me excited, especially the notion of a Prof. Gollhofer that he has clear evidence that there is another muscle receptor of which we know little so far, except that it has something to do with gravity. Plus a little quote from Prof. Essfeld that the vast majority of the sensory neurons which come from the muscles carry information of unknown content; i.e. researchers don't know what they are measuring. That made me curious. How about if this new muscle receptor had something to do with fascia or with our work?

My curiosity finally led me to do something I had never done before:

I grabbed the phone to see if I could talk to this Professor Gollhofer in person. I wanted to learn more about those gravity receptors in the muscles. Two days later (through the help of the directory information, his wife, and finally his institute) I got to talk to him. Yes, he could send me some articles of his recent research. And yes, this new receptor function was indeed quite likely embedded within the fascia, he said, since he and his American colleagues are now suspecting that this "new receptor" is basically a new function of the already known Golgi receptors in the fascia.

Golgi receptors? Aren't those the ones that John Cottingham had informed us about that are distributed all over in fascial sheets (and only 'more densely' in the tendinous endings of them), and about which he had suggested to us years ago that they are probably the main input devices for the immediate tissue effects in Rolfing? This new discovery now sounded like "hot stuff" for any curious Rolfer!

European train rides are good for studying

Dec. 94. A long train ride to Cologne to visit a Prof. Essfeld at the sports university there. He is among the leading experts in the study of the so-called "interstitial muscle receptors" which seem to operate quite differently than the "gravity receptors" of Dr.Gollhofer. (I had arranged to visit Dr. Gollhofer in January, but through his research literature I had learned about Dr. Essfeld and about this other research dimension of muscle receptors). Encouraged by the positive response from Dr. Gollhofer I finally called Prof. Essfeld in person and had arranged for a personal visit to his research laboratory in Cologne. Sitting in the train now I review again the stacks of material that he had sent me or that I had copied at his recommendation in the state library. His research deals with something that has already known since some time; namely the existence of so-called type III and type IV receptors in muscles. Sitting in this comfortable train I reviewed again what is written about them in my anatomy text book:

The sensory neurons from the muscle spindles are known as type Ia, those from the Golgi receptors as type Ib (since they are of a similar large diameter). Besides them there is also a type II receptor in the spindles which is considerable smaller, and only little is known about its function. And then there are even finer sensory neurons - type III the myelinated "fee nerve endings", and type IV which are unmyelinated. These are now commonly called interstitial muscle receptors, and about which almost nothing (!) has been known concerning their function until recently. The new research material I now had in my lap was quite intriguing: it pointed out that we have much more of those mysterious type III & IV neurons in our muscles than of the more common types Ia, Ib and II all together. (In numbers: ¾ of all the sensory neurons in a muscle belong to this group of interstitial receptors ... of which we don't know much at all. See Fig. 1).

Fig. 1:  Proportion of the amount of neurons in a typical muscle nerve:

motor:                        about one quarter

vasomotor:               more than one third

type Ia, Ib, II:           less than 10%,  from spindles and Golgi receptors

type III & IV:            30%,  from interstitial muscle receptors

It is now believed that the main function of the interstitial muscle receptors has to do with 'cardiovascular reflex control'. They seem to be excited by noxious and nonnoxious mechanical, thermal, and chemical events in the tissue and lead to changes in arterial blood pressure, heart rate, cardiac output and venous tone. The few research data that deal with which type of stimulation leads to which cardiovascular response, are very complicated, contradictory and confusing. Nevertheless the current interpretation is that evolution has established these reflexes as a means for regulating and monitoring the cardiovascular responses to muscle activity.

Interesting detail for us Rolfers: some of the type III receptors are already excited by 'light touch with a painters brush'. Which means that even light manual work can lead to local and general metabolic changes. "Yes", I think while sitting in this train, "that's interesting ... but not so revolutionary either". So I wonder if this visit is really worth it, if this man's work has anything to contribute to our field of Structural Integration. "Nevertheless he's a person", I think, "who is on the leading edge of neuromuscular research, and I could ask him some of my the dozen questions I have written down in the last few days. And what about the research that he did with astronauts in weightlessness a few years ago? Would that have any relevance to our field?"

Half a day later ... same long train ride back to Munich. My notebook is filled with hasty sketches, my brain is full, stomach empty, but I am pleased and excited. It's been a very inspiring talk with a very knowledgeable man. Many new insights, information, and new questions that I am now typing into my laptop ... while gently rolling down the Rhine valley and waiting for my meal and a nice glass of wine in this InterCityEurope dining compartment. Here's some of my notes:

· The type Ia & Ib receptors (in the spindles and Golgis) don't just register length and stretch, but also "unexpected shocks" to them. Aha, so slow stretch is not the only thing that might trigger and excite the Golgi receptors in our work. Maybe sudden jerky movements that some osteopath make could lead to the same result.

· Fascia is indeed very richly enervated with nerve receptors. Mostly with Golgi receptors (type Ib), which are more dense around the tendinous endings. Furthermore there are (as in all other muscle tissue) lots of those mysterious interstitial receptors (type III & IV) which are located mostly along the small vessels, plus some Ruffini and Pacinian receptors in the fascia.

· A revolutionary new insight from research with spastic people: the normal nerve impulses are often there, but they seem to be limited by 'connective tissue restrictions'. Recent research has apparently shown that spasticity of the feet for example can often be avoided by putting the feet into artificial dorsiflexion early on. This is indeed a reversal of what I had been teaching all these years. Like many others I had assumed that the spasticity in cerebral palsy children was mainly a neurological problem, and had often referred them to a good Feldenkrais practitioner instead. I would not do this anymore after this information ...

· Quote from Dr. Essfeld: "Our muscular system is much more than just an apparatus for movement, it is quite possible our biggest and richest sensory organ." He justified this by showing that it contains many more receptors than our skin, eyes, or an other sensory organ. Our 'muscle sense' conveys much more information at a time than any other input or output device in our body. That sounds almost like the opposite of what Peter Schwind was humorously suggesting in the 1992 Annual Rolfing conference (and to which most of us had been applauding at that time) i.e. that "muscles are basically pretty stupid."

· This one should be interesting for Hubert Godard, who often differentiates in his language between a more alpha-motor system directed movement style and what he calls 'gamma movement', or 'gamma touch' (which, as far as I understand,seems to be usually more desirable for the client and the Rolfer): In a recent experiment they switched off all the pyramidal (alpha motor) connections in monkeys. Yet to everybody's surprise the monkeys rarely exhibited any motor deficiency or any visible changes in their movements. It was only with some "very fast and precise finger-movements" that the researchers saw any difference. Their conclusion: alpha and gamma motor system probably are always cooactivated to the same degree in all our movements, no matter how consciously we plan them or do them. I must admit, I myself liked that "more scientific" language and differentiation in Hubert's work between alpha and gamma movement styles very much. But after this information I would feel as embarrassed to use it now as I felt about my (and several other's) distinction of "left brain" and "right brain behavior" in the eighties (which drives most neuroscientists crazy who now know better).

· A recent Swedish experiment demonstrated that a higher potassium concentration in the muscular blood supply leads to a higher excitability of the alpha motor neurons in that region. Conclusion: there are at least "some" reflex loops from the interstitial muscle receptors to general motor control. Part of myofascial work might involve triggering some of those myriad of fineinterstitial muscle receptors which then could lead to a tonus change of some related muscle fibers.

· Dr. Gellhorn's research with an astronaut during a space mission confirmed his previous experiments on earth, namely that some of the interstitial muscle receptors are getting stimulated by 'local changes in interstitial fluid volume'. Not bad for us. Then a Rolfer's elbow could stimulate them too, I suggest.

· A great one for Peter Schwind and all other fans of myofascial visceral work: according to Dr. Essfeld the suspensory ligaments of the visceral organs are "very richly enervated by sensory receptors". (Yet he confirmed my understanding that unless they contain some red muscle fibers, e.g. like the Treitz ligament , most of those suspensory ligaments do not have any ability to actively changing their length or tonus within a few minutes).

· The type II receptors (or secondary spindle endings) are probably part of the so-called "flexor reflex afference system" which organizes the withdrawal of a stimulated leg together with an extension of the other leg. Which means that they are probably not used for the coordination of normal movements, like the type Ia or Ib for example.

· The development of muscle spindles occured only with land animals during evolution. Phylogenetically the polysynaptic reflex coordination came first, and only later the monosynaptic one appeared. For this reason the current trend in motor science is to associate the spindles with the "antigravity system". This is supported also by the fact that our antigravity muscles are especially densely equipped with spindles. And even more interesting: Within the animal kingdom it is human beings whose musculature contains the highest proportion (40%) of those spindle-rich antigravity muscles.


How Prof. Gollhofer got interested in Darrel Sanchez' Tuning Board

January 95. Several weeks later I am sitting again in a train and typing in my notes from a very inspiring talk by Prof. Gollhofer, the man to whom I had talked on the phone about his research on the discovery of new mechanoreceptor functions that seem to be related to gravity. Again, previous to my visit I had studied several of his articles and went into the state library for some additional groundwork to prepare me. He was indeed very pleased by my interest and spent a good 3 hours with me in his laboratory. Part of that had to do with the fact that I told him about the work Darrel Sanchez and several other Rolfers are now doing with the new "Tuning Board" (the client stands on a board which has thick foam underneath in order to allow constant shifting of the board in response to the balancing pressure of the feet). He was very interested and excited about it, since most of his recent research was done with people standing on platforms and measuring their responses when the platform suddenly moves. Let me explain.

Earlier in the eighties, scientists studying the regulation of upright posture had already found that the leg muscles of a person standing on a platform which suddenly tilts forward or backward (i.e. rotation around a transverse axis) show balancing responses that are so fast that they can only be regulated by monosynaptic reflexes. Yet it was unclear which receptors are involved in that. Then Dr. Gollhofer and his colleagues found that when people stand on a treadmill which suddenly moves (i.e. translatory movement forward or back) the muscular response takes about twice as long. This second reaction pattern to a moving support surface involves a polysynaptic reflex loop that could reach as high as the medulla. Both reaction patterns work independently whether one has the eyes open or closed. Further research revealed that it also worked when the soles of the feet were anaesthetized, so the foot's pressure receptors could not be utilized to maintain balance. The really interesting question then came up: what tells us so quickly about the position of our gravity center in relation to the support base? There are apparently some 'gravity receptors' below the head which transmit information about the projected position of our body's center of gravity in relation to the feet.

During the last decade a research team under Pierrot-Deseilligny in Paris and Nashner and Prochazka in the United States have produced a lot of research in this new field of gravity related receptor functions. In some of his most intriguing experiments, Dr. Gollhofer studied these balancing reflexes in 10 subjects who were totally immersed in water in order to simulate weightlessness (with individually adjusted weightsuits and snorkels). Here their bodies were pulled against a platform under their feet (both in a vertical position as well as in a horizontal position). When the platform suddenly moved forward or back - in either a rotational tilt pattern or in a translatory movement - he measured the responses of their leg muscles. Again he found the same muscular reaction patterns with the same short latencies as within the normal gravity field.

Meanwhile through some recent animal research it has become evident that it is not a totally new receptor type which is responsible for this, but that it is the Golgi receptors in the fascia of the muscles that can act as gravity dependent receptors. Depending on outer circumstances they can switch over from sensing stretch to become sensitive receptor for these two different balancing adjustments. My question to Dr. Gollhofer was then: who tells those Golgi receptors when to work as gravity receptors, and in which pattern? His best guess: presynaptic information (or presetting, or presynaptic inhibition) from supraspinal centers; i.e. the brain tells them when to measure what.