What is Central Pain, at the basic level? We know it is acids around the neurons, which drive current successively through voltage gaged sodium 1.3 and calcium 2.2 channels, and ultimately, the TRPV-1 receptors, but what does it mean to the thalamus and cortex, which must lens it all into a sensation? The following are excerpts from a discussion conducted with one of our pain consultants, Dr. K McHenry, who had collaborated with our founder, Dr. Patrick Wall, in times past.
What is your theory of pain?
Thank you Kevin for your efforts at this site. I will attempt to give an answer of help to the layperson, while including a little higher grade theoretical information.
As is already known to you, the sheer imprecision of the terms used to describe central pain prevents any simplified discussion of it, in theory or otherwise. Therefore, I will speak mainly to pain in general, slanting the discussion to the central pains, which are most likely due to some kind of miscommunication between thalamus and SII.insula such that an oscillation, also called a reverberation, which is persistent, occurs. When someone develops a stroke which results in central pain, the second stroke most likely to abolish it will be a stroke in the tracts between the somatosensory area behind the central sulcus and the inferior parietal cortex. This is strong evidence that some sort of discordancy has developed between the way these two pain areas communicate.
If this fact alone were weighed, we might move to discontinue the idea of oscillations between the thalamus and somatosensory cortex. However, pain signal from thalamus goes to S1, S2, and insula, so given the coordination of input this implies, it is not hard to see why thalamic dysfunction is central to central pain.
Also, one must always remember the quote from Francis Crick, “A theory that accounts for all the facts is bound to be wrong, because some of the facts are bound to be wrong”.
It is self flattery to call the following a theory, because it is not readily testable, so it is merely a hypothesis. In a prior article here, the author mentioned someone who won the Nobel Prize for showing that memory is holographic. In other words, you can hear again in your mind a musical number, or see a person’s face, but you cannot create a pain sensation in the same fashion. Consequently, you have “forgotten it”. You can only remember the fact of having suffered. You cannot recreate it by memory.
However, despite the earlier Nobel, it is now passe to speak of memory as holographic any more. Instead, scientists prefer to speak of it as “holographic-like”.
The first hologram was invented long before the laser. By using interference between light from different directions, what creates colors on soap bubbles, color could be created.
Once light could be made pure, with the invention of the laser, holography was much, much easier. Crystals with multifaceted sides could be made so that the image looked like the real thing. You already know what a hologram is going to look like before you start rotating it, because you have seen the front. The laser can bounce off the sides of a crystal (lithium niobate is a common crystal used) so that a three dimensional image results, no matter from which direction the electrons are aimed at the hologram. The electrons excite and are focused by the crystal.
The holographic memory model satisfied everyone for a while, beginning about in the 1960′s. The problem is that all scientists everywhere had begun to come face to face with the fact that reality is not built like we would imagine. There was a great deal of uncertainty in things. The divisions of reality simply would not fit the data. Their minds were maturing on the idea of quantum physics, which obeys the Second Law of Thermodynamics, matter (and everything else) seeks the lowest energy level, and anything with any “ordered order” is NOT at the lowest energy level. Mathematical calculations had established that immediately after the BIg Bang, no matter at all existed, because the “matter” concentrated inside the black hole had exploded with such heat that no matter at all could exist for some time.
This was peculiar. Enough matter to make up the universe suddenly had no matter at all, beccause it was too hot for matter to form. Conclusion, Matter formed from cooled down energy. And if things seek the lowest energy level, how do we explain protons, or any “matter” at all? The answer was in uncertainty. Matter was energy at the greatest degree of uncertainty and in some unexplained fashion, “unordered order” facilitated this low energy state. It sounds like we are cheating, but if one considers that undordered order is order capable of emerging by being lensed or focused, it gets a little easier. This, essentially, is quantum physics. Oddly, this nonintuitive theory described the behavior of subatomic particles. It was hard to deny.
One could formerly speak of matter or energy, or matter and waves. With the development of quantum physics, this became more and more difficult. At a fine enough level, the definitions broke down. Even Einstein refused to accept that something could be both matter and energy. Over ten years time, he attempted to invent a “theory of everything” so he wouldn’t have to accept quantum physics. Later, he called his effort a huge waste of time.
As the science of MRI became really bigtime, it was only too obvious that the spin of electrons and associated energy (such as light) had some property of waves and some of the properties of matter. Wave scientists tried to describe reality using wave formulas, but it turned out that if you go small enough what you find is not waves and is not matter, but something in between, with some of the characteristics of both.
There was no reason to believe that electrons in the brain behaved any differently. This sort of thing began to eat at neuroscientists as well as physicists. They had formerly been prone to speak of the body and the mind as separate. So, then, what was the mind? Well, it was hard to say. The mind was awareness, but of what? Well, mainly it was awareness of being aware—that was the mind (to use some of Pribram’s terminology). If you take an image from a camera lens and take it out of focus you have a very crude hologram. The image is still right there, of course, but it must be brought into focus before it appears, and there it is, NOTHING was SOMETHING.
But where did the lensing come from? Is it inherent in matter/energy? Does reality have elements of both certainty and uncertainty?
Pain is a type of awareness, so where does it come from?
Since it was the only show in town, quantum mechanics, which really was borrowed from Heisenberg’s uncertainty mathematics and the Second Law, could not be ignored. The brain was a bunch of electrical signals, if it was anything. In fact, trillions of electrical signals, almost uncountable, were there, in “bits and pieces”. These signals seemed to be at the core of life, so what was life? Things were pretty tough to answer until some of the quantum experts began to take a look at the mind, or was it vice versa?
Whichever sequence you believe happened, they began to doubt that holograms were forming in the brain. And in fact, they do not. However, awareness and memory had many of the characteristics of holograms, which means the mind seemed to be the “emerging” of many hologram-like bits of matter/energy in the brain. What was the focus that turned this into thought? There is still no concrete answer, only theory.
However, we will not wait until consciousness is solved before we consider how pain might operate in the brain. Lensing by the brain of bits and pieces of activity, is how it is similar to a hologram.
It is there, but needs to be “lensed”. In the brain, there is this tremendous amount of information being passed, most of which is in meaningless bits and pieces, what used to be called “noise”.
However, certain brain structures appear to be able to “lens” the bits and pieces until something specific emerges, in hologram-like fashion.
The memory of pain does not follow this arrangement as we said, for we cannot recreate the actual sensation by thinking about it. Therefore, something different is going on there.
Pain must emerge, and be lensed in the present, without being capable of being lensed in the memory. It must return to bits and pieces. Yet, it is so specific while it is occurring, for reasons that survival could depend upon accurate analysis of pain, yet we are destined to forget it. This is at variance with most learning, but spared us some brain space to focus on survival NOW.
Consequently, pain was “subcontracted” out to different brain parts which were not designed to be lensed together at some future date.
The location, or body area, of the pain goes to the primary somatosensory cortex, S1, found just behind the central sulcus.
In front of the sulcus is the primary motor cortex, M1. Transcranial DC current applied to the Motor Cortex, or M1, seems to be able to treat central pain. This suggests a defocusing of the nearby SI, perhaps by supplying too much information.
There are not many good researchers on the thalamus, but most of them believe the thalamus writes software on the fly for the cortex, which is then attached to messages passing on up to the cortex. Using the word, “up” can be misleading, because it is likely that the information is already there, but has not been lensed, or brought into a form which is subject to a formative event by the cortex.
Models for the processing of unimaginable bits of synaptic information are difficult to come by. I apologize for bringing physics into it, but as you know, there is talk of dark matter in space. In my opinion, dark matter, and dark energy as well for that matter, are unseen because they cannot be seen. They are outside the mathematics of seeability and the mathematics of physics and will only be detected when we learn to change some of it into detectable form. It will then be realized to have been there all along. We know that every synapse and every nerve in the body fire constantly, but there are more synaptics possibilities than there are atoms in the known universe.
One must consider how thoughts emerge from nearly limitless possibilities and how one “spark” exists at any one moment to allow discrete ideation.
One could think of this as a rotating cone shaped hard drive, or a spinning top, standing on a point, of almost infinite information capacity. Spatially, it can be thought of with a hierarchy at the top. This is not your coventional hard drive since as the information emerges its nature depends both on the paths it has traveled to reach a point on the surface and on the lensing of it, ie the focusing of it by hologram-like functions.
The cone may be thought of as a “content” cone, and surrounding is a “comparator” cone. (Remember, this model works just as well if the content cone is stationary and the comparator cone are both stationary. Either could be computative, ie. moving. The content cone may be thought of as surrounded by this comparator or “template” cone, shaped to match the solid cone, but capable of lensing and also of detecting discordancy. For this model to work, the brain would have to have unimaginable capacity for synaptic possibilities; and in fact, it does. Every neuron in the central nervous system has perhaps six thousand synapses, and the permutations and combinations of such pathways, even allowing for strengthening of some synaptic pathways, results in a number that is greater than the number of atoms in the known universe.
The brain is no slouch when it comes to capacity. Ten trillion cells with six thousand synapses, the possible combinations almost reach mathematical infinity. How could a comparator be designed to manage such a quantity. The answer is that only with a comparator, which generalizes massively could such a quantity be abbreviated into something matching human thought. Eight notes in the scale and we have never run out of melodies. Now try ten trillion notes and you get the idea.
Discordancy itself is a lensing of sorts. When a spark passes between the two cones, an “awareness” occurs, which might be a thought, as modeled by the instantaneous sequences of many sparks, or it might be a sensation, also composed of many component focusings.
Is it possible to overlens, to overfocus? Could this sensory realm be the realm of pain? Does overfocused imaging seek a higher level of hierarchy to attempt to make sense of it? We do not know, but perhaps information is meant to be diffused, to havea soft focus, with sensations that are too intense having the potential to excite pain. Such an event at a high level of hierarchy would be more intense pain. Sensation itself, if it focuses out at too high a level may become pain.
I apologize for fanciful comparisons, but to assist in perception, think of the transporter in Star Trek. The bits of a human or object are disassembled and reassembled. Bits of nerve signal are actually assembled in the thalamus, and meaning made of it by the cortex. Since this whole process is quite comparable to holograms, scientists of consciousness speak of “hologram-like” processes. Since that is our era, we just as well use similar terms to describe pain, although it is of interest to consider how a template might perform matching.
The template comparator is not memory, nor is it reasoning, but it is plastic, meaning that the fetus may gather material for composition and construction of a template as life develops, along patterns buried in the DNA. Such a gathering would be influenced by the hereditary influences provided in formation of the organism via blueprints from our DNA.
In Rh disease, for example, it is necessary to transfuse O negative blood into the abdomen of an infant, perhaps several times. The blood vessels inside the abdomen are so thin that red cells deposited into the belly enter the circulation to replace blood destroyed by the mother’s immune system due to Rh incompatibility. The first time in, the fetus may lay docile, but the penetration by the needle teaches the infant something. On the second and subsequent transfusions, the fetus tries to move away from the needle. The fetus has perceived pain, so the template was in place, and got better in recognition due to experience. There is both a template and learning. Embryology now shows us that the orchestration of development is at a dizzying pace. Isoforms of peptides and proteins forming the body emerge and disappear and then reappear when it is time, in order for embryologic development.
A scientist might spend an entire lifetime studying the moments when the fetus is using the types of sodium ion channels, how it switches to another, and then switches back again at the speed of life. To make sense of these alternations is beyond our capacity at the present. We will need a supercomputer to analyze the choreography.
One could also argue that the pathways providing pain information were perfected by the first experience of the needle penetrating the abdominal wall (pain teaching or aversive learning) and this idea of synaptic strenghtening is almost certainly true. Yet, in some fashion, the brain must have been ready to compare, and must have a place to compare. This place is the template.
The model of a solid cone surrounded by an empty one, between which sparks may pass at levels of hierarchy is intended to be mathematical, not indicative of the actual shape of the brain.
The template is not not so much content, and it represents MANY templates, perhaps infinite in number, which cannot lens without being affected by the information in the content cone. Pain occurs when there is interaction between a template and information in the cone, information which appears to have concnetrated in the thalamus.
We must speak of things in flux to allow for the uncertainty mathematics, which quantum physics has shown is so important in the behavior or natural things.
When hierarchy, content, or their interaction is DISCORDANT with something the brain considers to constitute a focus or image, we have template mismatching. Remember, this is just a model, but it is consistent with the idea that our thoughts have something to do with who we are, and what we are.
As you know, the brain is most peculiar, because it seems almost as if there is a place for ANY kind of learning. Its state of readiness is such that it appears to be prepared for any idea, and in fact, “sees it coming” (which more or less recapitulates what Dyson said about how the universe fits together).
No matter what the idea, learning, or reasoning, the brain has a place for it. It is ready, or one is soon made ready. That is something to think about. Somehow, buried in our DNA is the creation of an organ which is in sync with the universe. To say it more poetically, we are “Children of the Universe”.
The English language resides in one part of the cortex, Spanish in another, etc. This sll suggests that as the brain develops, it allocates the lensing of various kinds of information according to species capacity.
The brain has many actions which we speak of as vegetative, but what we think of as consciousness involves activity in parts subject to acute examination, with a special type of processing. The roots of pain are in the vegetative, but it may be lensed into being by the conscious.
In an organ of such incomprehensible complexity, it is not hard to see that small imbalances might lead to serious consequences. An earlier article at painonline showed that experimental nerve injury leading to central pain result in merely quadrupling the number of glia in the dorsal horn of the cord. Yet, in an organism where homeostasis is one of the prime rules, capable of deriving great information from subtle nuances in signal, quadrupling is more than sufficient to explain drastic hypersensiization and really severe pain. If lensing of pain is diminished by one fourth, it takes no imagination to realize that marked derangement might occur.
The very universe we live in exists on the “knife edge of improbability”, as Collins stated. So many physical factors, if even differing by a millionth of a millionth of a millionth part would make not only life, but the universe itself impossible.
An intact pain system does not require much alteration of the thalamocortical oscillations to dredge up some truly awful feelings and sensations. The tolerances appear to be very finely tuned, and it is a marvel that more people are not caught up in the throes of really terrible nerve injury pain. It is not such a stretch to let the public know that light touch can be really unbearable in CP.
Pain has both vegetative and cognitive aspects, and because injury to either the reflex arm or the analytical arm can result in a pain state, it seemed that patterns of normality must exist, against which incoming information is compared. This is where the idea of template matching came from.
In a computer, you cannot uninstall a program if part of it is still running. The parts have to be available and free for access to be uninstalled. It would seem as if some of the identical structures which create pain sensation also eliminate it. It is perhaps possible to muddle the driving chemistry of these structures.
Deranging diffusion of signal at SI may give just enough redirection to allow pains to be partially “uninstalled” (ie central pain could be decomposed somewhat) in ongoing fashion without intefering totally in the pain operation. This should lessen pain, paradoxically, by increasing the information.
Alternatively, spillover from M1 may create “troughs” of statistical likelihood of signal arrangment so that information flow is rerouted just enough to prevent accurate lensing.
The significance of any physical pain is processed by the operculum, which is called SII, which is in the lower part of the parietal lobe.
Finally, as the article at this site by Crick, as well as his landmark article in the Journal “Pain”, showed, the “painfulness of pain” is processed in the insular cortex.
The insula is an area at the lower sides of the brain which is hidden by folds of the parietal and temporal cortex which grow over it, sort of like what is inside the cuff of trousers.
In addition, there are many other areas which process pain in certain ways, such as the cingulum, which tells us the pain “belongs” to us and not someone else. Oddly, there are patients with damage to this area who may say, “Uh oh. Someone in this room has terrible pain and is really in trouble”–they may have the emotional reaction to pain, but do not own the pain. Various pain areas are spread all over.
It may be that the spread of operations prevents hologram-like memory of pain. Reassembly does not occur because the parts are not wired to “run backwards”. It may also be that these areas are “running”, or “on alert” for present protection and so cannot be utilized to recreate a pain memory, which may require them all. The memory of “having suffered” is of course available to humans–we just cannot recreate the actual sensation in our minds.
These are the types of things neuroscientists discuss in their idle moments. Is any of it correct? Perhaps yes. Perhaps no. However, it may be that the spatial separation and subdivision of pain aspects, and their ongoing “running” prevents lensing at a later time, which prevents hologram-like memory of pain.
It is interesting to think on such things. It is also more consistent with our developing idea of the mind as representing the emerging of defocused energy, and both nociceptive and neuropathic pain as “lensing” of bits and pieces of information passing through the thalamus and cortex.
Fifty years from now this will probably all be solved. In the meantime, we hope to see pain effectively blocked much sooner, perhaps by preventing neuroinflammation or by flooding one of the core assembly mechanisms.
Right now, it appears that making the motor cortex run harder, makes the pain apparatus less able to coordinate the lensing of pain–if one believes quantum physics has anything to do with it. Flooding may not be necessary, if we can find a way to achieve total blockage of proteins in the ion channels. Right now, drug blockage attaches to small portions of the molecule, the remainder is inside the folded protein. If we try to cleave the protein, then it is worse because of neuroinflammation. Fortunately, the chemicals which activate ion channels are small and should be relatively easy to work with. Deformation of the channel proteins with peptides is also a possiblity. There is even a peptide which puts people to sleep, and that area deserves close attention.
Models help us to conceive of how to study pain. They are not truth. Pain appears to be the repetitive emerging of a pattern created by the brain. Discordant information, lensed poorly, and high on the hierarchy is what we seem to have in central pain.
Dr. Patrick Wall and I considered these matters and Dr. Wall was convinced that a template for normality existed in the brain, pain being a non-matching of the template. I was inclined to agree with him. Where we ultimately differed was that I saw pain as occurring discretely and not facing a broad template for comparison, ie. that a tiny locus of disagreement occurred, with realization of what that “spark” of disagreement represented occurring in designated portions of the brain elsewhere, perhaps far away, and perhaps in large areas. My reasoning was to allow for distraction by the thought process, and enhancement by stress, and the relatively inconsistent behavior of the central pains.
I also saw severe central pain as able to recruit nearly the entire brain resources. A potential for almost global involvement might explain the failure of pain memory, since the brain would later refuse to devote the resources necessary to recreate the memory, since they were needed to be on alert in the present. The cortex should also be able to have a hierarchy of severity, as well as spatial differentiation of template non-matching. Mere changes in this heirarchy of severity could convert light touch into pain, with a possibility but not an absolute necessity for template mismatching. Template plus hierar