Basic Training Series: Nervous System Principle #8: CHEMICAL MESSAGE CODING

OKAAAAYYYY...

Here's the last one according to Angevine. Before I get into it, I want to say thanks to those who have been reading these posts. It's been a tremendous education for me to learn these principles. Now that I have them under my belt, so to speak, I will get more detailed with form and function.


"Chemical Message Coding
The basic function of the nervous system, from which all others derive, is communication, performed (with unsung neuroglial support) by neurons. It depends on special electrical, structural,and chemical properties of these diversified cells with their long processes, on their exploitation and refinement of two basic protoplasmic properties, irritability and conductivity, on their external and internal neuronal morphology featuring multipolar shape and integrative design, almost infinite modes of dendritic and axonal branching, widespread, diversified connections, and specialized organelles, and on their use of chemical substances to encode, deliver and decipher messages of their own and other neurons.

Neural circuits are chemically coded. Neuroanatomy encompasses interneuronal connections and also chemical mediators and transmitters. Neuroactive substances comprise neurotransmitters, neuromodulators, and neurohormones. Their definition in contexts other than site of action, postsynaptic neuronal activity, and corelease of one or more additional neuroactive substances can be misleading. Neurotransmitters are small molecules acting swiftly, locally, and briefly on target cells. Neuromodulators are very small (peptides), regulating but not effecting transmission, and neurohormones are also small, with intrinsic activity mediated by neuronal and other cells, exerting slow, widespread, and enduring influence via the extracellular fluid or bloodstream.

Neurons releasing hormones are quasi-endocrine cells, liberating secretory products from axonal endings into the perivascular space to be conveyed to blood vessels and thence to target organs. The provincial concerns of neurophysiology and endocrinology have fused into neuroendocrinology, as psychoneuroimmunology has united psychobiology, molecular neurobiology, and immunology."

Last one but so important as it deals with how the Neuromatrix sends signals all over the body. 

1) I love that Angevine says that "The basic function of the nervous system, from which all others derive is COMMUNICATION (with unsung neuroglial support) by neurons." 

2) These neuromodulators, neurohormones and neurotransmitters are essential to every function in the body. From all my research we are JUST starting to understand how powerful and influential these are. Of course pharmacology has been dealing with them for a while but the extent to which all of the above neurochemicals are affected is not fully known. 

For a GREAT book that is easy to understand, see Robert Sapolsky's "Why Zebras don't get ulcers". This book talks about Prof. Sapolskys favorite topic "glucocorticoids."

Honestly, this topic can is become complicated quickly, so I'm going to leave it at that. I look forward to learning more about them as it's important to trainers and therapists to understand that while we cannot directly affect the chemical coding, the process can be affected by something as simple as proper nutrition. 

Well, that's all for the Principles of the Nervous System.


Again, thanks for reading, and if you have questions or comments, please do not hesitate to post them.

In mind, body and spirit,

Will

Basic Training Series: Nervous System Principle #7: PLASTICITY

Okay, here's Principle #7, according to Jay Angevine:

"Plasticity
Highly reliable in a healthy person, the human nervous system has inherent modifiability, though in adulthood this attribute cannot approach that in invertebrates (moths and snails) or certain other vertebrates (teleosts and amphibians). In mammalian development, neural plasticity is striking. In continues postnatally. Abnormal visual experience at certain sensitive periods profoundly affects ocular dominance and orientation columns in the visual cortex. If an eye is closed at birth, ocular dominance columns for the other eye enlarge at the expense of adjacent blind eye columns, with thalamic fibers arriving in the cortex expanding terminal fields into them. If, shortly after birth, visual stimuli are restricted for a few weeks or even days to stripes of one orientation, cortical cells develop a response preference to lines of that orientation.

In humans, PET imaging studies of cortical blood flow show that tasks requiring tactile discrimination activate visual cortex in people blind at birth or having lost sight in childhood. This suggests that cortical connections reorganize after blindness: that afferent fibers to nearby cortical areas serving polymodal sensory integration usurp the bereft visual cortex. Such plasticity may explain the well-known tactile acuity of the blind.

In later development, neural plasticity operates on many levels, as in fine-tuning circuits to changing body dimensions. Depth perception is recalibrated as the skull enlarges and interpupillary distance increases. Even in adulthood, plasticity persists. Vilayanur Ramachandran has shown that a stroke with a cottonswab on the cheek of a young man who had accidentally lost his left arm led him to feel touch on his missing left hand. Later, the whole hand could be mapped on his face. The findings suggest that the deprived somatosensory cortical region for the hand becomes innervated by fibers from the adjacent face areas and that secondary input to a cortical neuron's broad receptive field becomes functional when primary input is lost.

After injury to the CNS, intact neurons form new terminals, by axon sprouting, to replace those of other neurons lost to trauma and thus reoccupy vacated synapses. Such reactive synaptogenesis, the clinically proven effectiveness of long-range regrowth of PNS axons, and the evident potential for axon regeneration in the CNS (as in teleosts and amphibia) hold promise for circuit reestablishment. But in mammals, these factors are thwarted by myelin debris, glial scarring, usurpation of sprouts, unresponsive injured neurons, and complex central connections. Developmental neuroscience now focuses on the cerebral cortex. The human nervous system appears to learn very rapidly by using preconstructed circuits and by locking neurons into specific types and functions after cell origin."

So this one is just AWESOME!  I was first introduced to this idea of "neuroplasticity" in the book The Brain that changes itself by Dr. Norman Doidge.  This book pretty much changed my life and the way I approached therapy and training/conditioning. I COULD go on and on, but I'll keep this one short too. Here goes my observations:

1) The first sentence mentioned in the HEALTHY person that the nervous system is able to be modified but no where close to invertebrates like moths and snails. However, it is still impressive. 

2) Dr. Angevine then goes into an example of how loss of sense like vision affects the brain. It seems the  neural resources that would have been utilized for vision are re-appropriated and still used. It seems the system has inherent intolerance for low usage of important structures and systems. 

3) A special interest to therapists and trainers, the nervous system changes based on dimensions of the body. Well, this is pretty intuitive. Something happens in the body (the skull was used by Angevine) and the nervous system recognizes this and adjusts so as to keep the body trekking on. Amazingly, all of this is under our "conscious" radar.  

4) When there is an injury to the body, like a loss of a limb, research has shown that plasticity starts remapping and the sensations of the lost limb can still be "felt." Ramanchandran demonstrated this when by touching the face of a patient who had lost a limb but the tactile sensation was still experienced. Whoa! 

5) In the final paragraph, Angevine discusses how the when the CNS is injured it can replace some of the structure in FROGS. Ugh... He explains that the other body processes that accompany the injury can thwart the regeneration; HOWEVER, there was some research done that stated:

"Wernig et al in Proc Natl Acad Sci U S A May (2008) have achieved a real breakthrough. They have been able to convert fibroblasts to neurons. These converted cells form into neurons, glia, and even dopaminergic cells. There has always been concern that converted cells might form tumors, but these scientists painstakingly separated the cells turned into neurons from pluripotential cells with fluorescent stains."

So, there's hope after all. Ordinary cells can be converted into neurons given the proper transcription factors. 

This principle is so important to me as a therapist, trainer and coach as we see that changes can occur not only in the body but in the all important nervous system. If our brains couldn't adjust all the REMARKABLE changes that took place in the mesodermal-derived structures like bones, joints, muscles, fascia, etc, we would be always be stuck mentally "small" in a "big" container. I don't think that would be too much fun. 

Anyway, this post is running long, so I'll cut it short here. 

Questions? Comments? I'd love to see what you're thinking!

In mind, body and spirit,

Will

Basic Training Series: Nervous System Principle #5: PURPOSEFULNESS

Now we turn to Principle #5: PURPOSEFULNESS.

Here is another except from Dr. Jay Angevine's writing from the Encyclopedia of the Human Brain.


"The Purposefulness of Neural Components
Every part of the nervous system has at least one function, often many more. Small parts of the CNS may play crucial roles, as in the extensive distribution and profound influence of axons from inconspicuous brain centers. The locus ceruleus ("blue spot") on each side of the fourth ventricle contains about 12,000 large melanin-pigmented neurons. These synthesize norepinephrine and release it in the cerebral cortex, cerebellum, and almost every other part of the CNS. Electrically, they are almost silent in sleep, hypoactive in wakefulness, and hyperactive in watchful or startling situations. They serve vigilance and attention to novel stimuli. They contribute, indirectly but no less crucially, to perceptual and cognitive functions. By contrast, immense structures make large but expensive contributions, as in the cognitive and motor abilities afforded us by the billions of neurons in our cerebral and cerebellar cortices."


Even though the above paragraph is shorter, it's no less important to understanding that the EVERY part of the nervous system, has a purpose to it. No matter how small. Here are some things I picked out of it.

1) As I stated before, everything from the smallest "part" to the largest has a purpose or several purposes that we CURRENTLY know of; however, I am willing to bet that changes frequently as the science delves deeper into the NS.

2) I think a lot of folks concentrate on either the peripheral or central nervous systems but it seems that EACH part of each system (which is MANY) has a purpose and together those purposes start to add up into something that we really do not fully understand. Just my humble opinion.

3) The example about the locus ceruleus was great as it gave insight to how a small part affects the overall organism. This "small" part releases a very important chemical into critical areas of the brain which are charged with larger tasks like cognition and perception. Whoa. So what happens when one of these "small" parts stops working? Hmmmmm.... chaos maybe? For instance, the locus cereleus secretes norepinephrine in the brain, and its main function is directing attention to novel and potentially challenging stimuli.  Recently, they found that the LC also suppresses neruo-inflammation in the brain through the norepinephrine secretion. This is important in Alzheimer's Disease as there is a progression of the disease after the destruction of the LC.  The cognitive decline is well documented, so we see how small parts affect the whole.

4) Finally, the author informs us that the immense structures "make large and expensive contributions" like thinking and moving. Pretty important! Diane Jacobs, PT, always remarks how the nervous systems makes up 2% of the body BUT utilizes 20% of all resources in the body. If someone wants to debate the PURPOSEFULNESS of the nervous system, I'd like to see them do it without their cerebral cortex. ;-)

Pretty cool, stuff, huh????

I hope you are getting excited as I am about the Nervous System. The next post is Principle #5: UNIFORMITY WITH VERSATILITY.

Questions? Comments?

In mind, body, and spirit,

Will

Basic Training Series: Nervous System Principle #4: SPECIALIZATION

Okay, here we are at Nervous System Principle #4: Specialization. Lots of rich info here and a bit of foreshadowing into the complexity of the system.


"Specialization"
Reflecting its diverse tasks, the nervous system is specialized, from the single neuron to each brain region. Specialized subsystems analyze sensations. They differ in some ways, but data processing is progressive and networked in all. Neurons and the neuroglia have special shapes and roles, but both enjoy all criteria for cells and work in concert. Less obvious but equally specialized are subsystems for other functions: sleep-wakefulness, alertness, attention, affect, collating pages of a report, reading out loud from a book, self-awareness, brain damage control, and so on ad infinitum. 

Ubiquitous specializations include those for high nerve conduction velocity (large axon diameter, thick myelin sheath), space-saving bundling (small-axon diameter, thin myelin sheath, shared sheaths), short latency response (monosynaptic reflex), staggered, persistent latencies (parallel side chaining of long-axoned neurons), dependability (neuron redundancy), feature analysis (parallel processing), effect monitoring (feedback circuits), and force multiplication (feed-forward circuits). The neurons performing such tasks and the neuroglia backing them up are as specialized as these many diversified services. For neurons and the neuroglia, form indeed reflects function."

Now, this is just getting interesting! Looking at the paragraph above, I had to stop and do a little research about these specialized subsystems. To be honest, that will take SEVERAL posts and not something I want to go into now because ...well, I don't understand it fully. Later on that. 

Anyway, here's what I gathered from this excerpt:

1) The nature of the Nervous System is diversity in its activities, so this necessitates subsystems that are delegated for each task with the accompanying specialized "equipment" of neurons and neuroglia for support. 

2) Different subsystems analyze internal and external sensations. 

3) Even though the neurons and neuroglia (support staff for neurons) have different shapes and sizes, they are still cells and work together for the greater good of function. 

3) The nervous systems subsystem tasks are numerous and make up activities like wakefulness, brain damage control, alertness, attention, etc. 

4) The second paragraph gets into the specifics of how the specializations are combined and their resultant activity like feed forward and feedback circuits. We see how this is vitally important to the entire body in terms of organism survival and homeostasis. 

Another WOW moment for me as this Principle  touches on how the nervous system is ORGANIZED so that it can carry out functions. 

As promised, I'm keeping these posts shorter. 

Lookout tomorrow for Principle #5: PURPOSEFULNESS

Questions or comments, please let know.

In mind, body and spirit,

Will 

Basic Training Series: Nervous System Principle #3: Centralization

A PRINCIPLE is defined as "a comprehensive and fundamental law, doctrine or assumption." These principles are necessary to have a simple perspective of a very complex system. As I have started to learn more about the Nervous System, I have found that remembering these 8 Principles has made it easier to get through complexity to the simplicity of it all.

Here is Dr. Angevine's Third Principle of the Nervous System:

CENTRALIZATION

"The key feature of the nervous system is centralization. It offers few circuits for local interactions of body parts. The CNS is almost always involved even if the distance, as from thumb to index finger, is slight. Intercession of the brain and spinal cord ensures integrated and coordinated activity. 

Exceptions are instructive. The local cutaneous response to irritating stimuli (raking a blunt probe over the skin) has three components: local reddening (vasodilation from injury), wheal formation (transient edema from tissue fluid extrusion), and ensuing vasodilation (flare) with lowered thresholds and increased sensitivity to pain (pinprick). The flare and hyperalgesia represent an axon reflex. Nociceptive (pain) nerve endings are activated by substances released by injured tissue cells, and nerve impulses are conducted a short way centrally along nociceptive axons and then distally over branches of these axons to nearby arterioles, causing them to dilate. Advanced or primitive (it is sluggish, starting in about 20 sec. and developing fully in around 3 min), this reflex involves local nerve fibers only, not the CNS.

The "triple response" illustrates three concepts. Pain receptors sense chemical, as well as mechanical and thermal stimuli. Their sensitivity is increased by substances accumulating in the damaged area. Their response includes a neuroeffector component. They release substances (peptides) that initiate further events, providing further protection and favoring local tissue repair. 

Studies in invertebrate neural systems show extensive local control of visceral function. Exceptions to central control are also found in the mammalian ANS. Near-normal interaction of bowel segments persists in the absence of CNS innervation. Sensory fibers from the gut exert feedback in intramural autonomic ganglia on visceral motor neurons regulating smooth muscle in the intestinal wall. The nervous system has pattern generators, both central and peripheral: systems with cellular, synaptic, and network properties (cyclic firing rhythms, reciprocal inhibition of cell pairs, leader and follower cells) that provide automated mechanisms for generating rhythmic movements (breathing, walking) or periodic activities (sleeping, waking). Regulated by neural (sensory feedback, volitional override) or neuroendocrine influences, pattern generators are pithy examples of neural endogenous activity." 

Okay, looking at the above passage, I was a little confused for a bit but simplicity bit me in the backside again. Here's what I got out of it:

1) MOSTLY everything gets reported to and controlled by the central nervous system with a few exceptions which are important and "instructive" as Dr. Angevine says.

2) Regardless of distance in between two segments, the CNS is still involved.

3) The exception of when the CNS is not involved is something like a scratch to an arm that creates a local response of reddening, swelling, warming all which creates a stimulus to the nociceptors which CAN create the experience of pain. Since there is a local "axonal response," there is no requirement of integration and permission from the CNS. Given the givens, I can see why this is evolutionarily necessary. The body is going to, first and foremost, deal with survival as efficiently as possible, so including the CNS in an injury like that would be less than necessary initially. Eventually, it gets to the CNS though. Please don't forget that.

4) The enteric or "gut" nervous system does not require CNS innervation to function.

5) The nervous system has pattern generators that allow it to function efficiently and effectively that are regulated by neural or neuroendocrine influences.


That's enough for now. Stay tuned for the Principle #4: SPECIALIZATION.

I'd love to hear from you. Please let a comment or question.

In mind, body and spirit,

Will

Basic Training Series: Nervous System Principle #2: UNITY

A PRINCIPLE is defined as "a comprehensive and fundamental law, doctrine or assumption." These principles are necessary to have a simple perspective of a very complex system. As I have started to learn more about the Nervous System, I have found that remembering these 8 Principles has made it easier to get through complexity to the simplicity of it all.


Staying with Dr. Jay Angevine from the Encyclopedia of the Human Brain, we are now at Principle #2 of UNITY.



"Unity"
As in epithelium, all parts of the nervous system are physically coherent and functionally linked by nerves, tracts, and specified cell to cell contacts. Potentially each part communicates with all others. Some connections are direct (a two-neuron, monosynaptic reflex), whereas others involve myriad interposed neurons. Though complex, neural circuits offer total connectivity: fast, body-wide communication. Nerve impulses may originate in sensory nerve endings in any part of the body or anywhere in the system itself. Responsive activity complements endogenous activity, which is always evident in the human nervous system with its startling capacity to generate patterns of behavior and initiate events on its own. Sensory impulses, triggered by PNS primary sensory neurons, race over its nerves to the CNS, there diverging to clusters of secondary sensory neurons. Analysis begins. New impulses pass to central neurons on which related messages converge, which is a recombinant process providing integration. Other messages on stimulus modality, intensity, location, affective quality, body position and movement, visceral activity, fatigue, experience, and expectations are all integrated. Huge numbers of impulses are generated; untold numbers of synapses are activated. Almost instantly, nerve impulses that will elicit bodily responses stream out of the CNS to muscles and glands."

Wow! Wow! Wow!

What an important principle of understanding the nervous system. IT'S ALL LINKED TOGETHER! Not only is it everywhere, but it's physically coherent for maximum effectiveness. Here are some gems that I took from the above paragraph:

1) Again, IT'S ALL LINKED TOGETHER. 'Nuff said. 

2) The system is communicative in nature with every part potentially being able to talk to every other part. The mode of communication (monosynaptic reflex neuron, myriad interposed neurons, etc) may be different but the end result is TOTAL full-body communication required for action.

3) The nervous system is aware of what is going on in the body at all times and is complemented by bodily responses. Because of this awareness of activity, it is able to make decisions and carry them through for the organism.

4) Because of it's unity, information of ALL kinds is gathered from the periphery and communicated to the Central Nervous System where it is then processed/integrated and turned into action.

5) All of this processing requires MANY impulses to be generated from countless synapses from countless CONNECTIONS which almost instantly creates output of some kind to muscles and glands. 

It's easy to see why UNITY would be so vital to the nervous system as it controls everything we do on conscious and non-conscious levels. If there were a break in the unity, we would see varying levels of dysfunction and distress throughout the system.

Check back Principle #3 of CENTRALIZATION.

Questions or comments? Please do not hesitate to post.

In mind, body and spirit,

Will 

Basic Training Series: Nervous System Principle #1: UBIQUITY

A PRINCIPLE is defined as "a comprehensive and fundamental law, doctrine or assumption." These principles are necessary to have a simple perspective of a very complex system. As I have started to learn more about the Nervous System, I have found that remembering these 8 Principles has made it easier to get through complexity to the simplicity of it all.

Let's continue.

Here we are at PRINCIPLE #1 of Ubiquity.

According to Jay Angevine, PhD in the Encyclopedia of the Human Brain:

"Ubiquity
With 100,000 miles of nerve fibers the nervous system rivals the vascular system. Both pervade the body and function in harmony. By nerve impulses or circulating red and white cells, glucose, hormones and immune principles, they integrate body activity, protect the body, enhance its performance to met stress or demand, promote its growth and nutrition, and maintain its tone and vigor. The trunk and branches of both systems reflect body form. If either system and no other part of a person were visible, he or she would be recognizable. Density of innervation varies as the value of parts to sensory discrimination or motor control. In well-innervated areas (lips, fingertips) stimuli are sharply discriminated as to modality, intensity, and location, but in sparsely innervated areas (flanks, legs) these are less defined. Similarly, muscles vary in the ratio of motor neurons to muscle fibres. The higher the ratio, the more precise the control of the muscle and the movement it serves (a motor neuron may excite 2000 muscle fibers in a limb muscle or as few as 5 in extrinsic ocular muscles)."

Here's what jumped out at me: 

1) There are A LOT of nerve fibers in the body. Literally everywhere so there must be something to it, and if we ignore it, we are ignoring a HUGE component of the body. 

2) The nerve fibers and the veins/arteries pervade the body and work to keep the body in function and harmony. 

3) The body will have more or less nerve fibers in a particular area based on sensory discrimination or motor control. 

4) In highly innervated areas, sensory input will be distingushed shaped by modality, location and intensity. 

5) In lesser innervated areas, the sensory input discrimination will be less.

6) For finer movements, the ratio of motor neurons to muscle fibre matters since a smaller innervation ratio will resort in more subtle control. For instance if there is a 1 motor neuron to 5 extrinsic ocular muscles, there will be more control. Large motor neuron to muscle fibre ratio, for instance in the thigh muscles (1:2000+), will be the opposite, as far as motor control goes.


So where does this leave us?

Honestly, that is a lot to take in and will greatly help understanding when we start getting into the nitty-gritty of sensory input and motor output in regards to movement (therapy and training/conditioning). Getting into which structures do this is important; however, going in with the principle that the nervous system ubiquitously manages input and output of the body is powerful.

Questions or comments? I'd love to hear from you.

In mind, body and spirit,

Will

Basic Training Series: Introduction to the Nervous System: PRINCIPLES

Well, I am back! It's been MANY months since I wrote something in the blog and to be honest, I missed it.

Anyway, I am back and wanted to get into writing something that is near and dear to me: THE NERVOUS SYSTEM. Don't worry. This wont be the only thing I write about but it will be among the central topics that I write about. It's my blog. I can do whatever I want. hehe

Okay, let's get to it:

(Before I begin, I want to PROFUSELY thank Canadian phyiotherapist, Diane Jacobs, for helping me understand this complex system. Hopefully, ONE DAY, I can have an iota of her profound knowledge of the system. THANK YOU, DIANE!!!)

 Here are some quick facts about the Nervous system according to Jay B. Angevine at the University of Arizona written in the 4-volume Encyclopedia of the Human Brain, 2002, edited by V.S. Ramachandran. 

• 100 billion neurons of 10,000 types, 
• 1-10 trillion neuroglial cells, 
• 100 trillion chemical synapses, 
• 160,000 km. of neuronal processes, 
• thousands of neuronal clusters and fiber tracts, 
• hundreds of functional systems, 
• dozens of functional subsystems, 
• 7 central regions
• three main division

Wow! That is a lot to take in, so given the sheer volume and complexity of it, I can see why it's so hard to understand. In this "Basic Training Series", I'm going to try and break the Nervous System down into something that is easier to understand. Let's see what happens. 

BASIC PRINCIPLES OF THE NERVOUS SYSTEM

Jay Angevine writes about the 8 Principles of the Nervous System in the Encylopedia of the Human brain. They are:

1. Ubiquity
2. Unity
3. Centralization
4. Specialization
5. Purposefulness
6. Uniformity with Versatility
7. Plasticity
8. Chemical Message Coding

I am working to keep my writing short these days so I'll go through all eight in separate posts. 

As always, if you have any questions, please do not hesitate to ask. 

In Mind, Body and Spirit,

Will 

Hiatus over! Interview with Dr. Roy Sugarman

Dear all,

I'm back!!!

It's been a while and I'm sorry I have not been attending to the blog that much. It's been quite a few months as I have moved into radio as well.

I'm going to post a few of the interviews up as well as some videos. They are awesome if I do say so myself.

This first interview is of me and Dr. Roy Sugarman of Athletes Performance. Roy is the Director of Neuroscience there so we were able to talk about that aspect of performance and how mindset really affects motor control.

Coaches and players out there, take note that if you are distracted or have a bad attitude, those thoughts actually affect the motor control centers of your brain. Bad attitude = Bad performance.

Enjoy the interview!!!


Will

Listen to internet radio with thrill96 on Blog Talk Radio

Explain Pain: Part II with guest writer Anoop Balachandran

This post has been a LOOOOONG time coming but I have been really busy with various interviews that I will post later. My friend, Anoop Balachandran, wrote this post on pain and I thought "Why try and reinvent the wheel?"

Thanks Anoop!!!

By: Anoop Balachandran of ExerciseBiology.com

Just like many fitness professionals and lay people, I used to believe that pain comes from an injury or damage caused by misaligned joints, weak and tight muscles, ruptured disks, bad posture and so on. This was based on the Cartesian model of thinking proposed by the philosopher Descartes almost 450 years back. Descartes wrote, “The flame particle jumps from the fire, touches the toe, moves up the spinal cord until a little bell goes off in the brain and says, ‘ouch. It hurt’.”

Figure 1: Cartesian Model

So it made a lot of sense to me when many physical therapists strengthened and stretched the muscle to treat pain, chiropractors tried to snap misaligned joints back to alignment, when physicians tried to diagnose and identify the damage causing the pain, and expensive tools like MRI and CT scans were recommended to spot the cause of pain. So just like any other passionate personal trainer, I too worked on correcting my client’s posture, finding their movement dysfunctions, correcting their imbalances, and performing trigger point therapy to ‘fix’ the pain in my clients.

In some of my clients it worked, in some it didn’t, and the rest ‘acted’ like it worked. This piqued my curiosity to research more about pain and converse with people who were a lot more abreast with the pain research and its application. And to be honest, it turned out be a very humbling experience.

It seemed like my understanding of pain was far from being complete and was missing some very vital information. So without further ado, here is what I learned:

So what is missing in our understanding of pain?

From what we remember from our undergraduate textbooks, when you get hurt the pain receptors send pain signals up the brain and we sense pain. So if pain is indeed an accurate indication of tissue damage, tell me:

• Why do 40% of the people (alert, rational & coherent and “not in shock”) admitted to an emergency room with horrific wounds feel no pain or pain of low intensity even after long delays? (1)
• Why do studies repeatedly show gross abnormalities, like disc bulges, spinal stenosis, herniations, meniscus tears, and so on in 20-70% of people who have no history of pain? (3,4,5).
• Which treatment would help in relieving the pain experienced by amputees in their “missing limb”? And 70% of the amputees report limb pain and sensation even years after the amputation (2).
• There are thousands of amputees running with prosthetic limbs and cerebral palsy patients walking with worst gait possible. These folks have more than 100% movement dysfunctions. Why are they not in bed wreathing in pain?

There are a lot more questions which the simple Cartesian model of pain has no answers.

So what is this revolution in the understanding of pain science?

The topic of pain is extremely complex to say the least. The below points are just a short summary of some of the major advancements in our understanding of the science of pain.  Mind you, the researchers knew about all this at least a decade ago, but the practitioners just happened to be late in understanding these concepts (just like in most fields).

1. There are no pain receptors

Pain is often thought of as a reflex mechanism. When you get hurt, the pain receptors send pain signals up to the brain and we sense pain, right? Wrong.

We have no ‘pain’ receptors. It is physiologically more correct to call them nociceptors because they are very similar to other receptors which sense temperature, pressure, and chemicals (called non-nociceptive receptors). The only difference between the two is that the nociceptors have a higher threshold than the non-nociceptors and are only activated when the stimuli is in the higher range. Contrary to what most people believe they don’t send ‘pain’ signals, they send  the same signals as other non-nociceptors but just at a higher threshold.

2. Pain is in your brain

When these ‘warning’ signals from the nociceptors reach the brain, it is up to the brain to decide whether it is indeed a real danger or not. You will not feel pain unless and until the brain believes that there is a threat to the body and hence an action is required. This has been shown in numerous studies both in animals and humans 6,7,8). In other words, it’s not the signals that go to the brain from the body that matters, it’s what the brain decides to do with these signals that matters.

This perhaps explains the countless examples we see of how people come to the emergency room with limbs missing and other horrific injuries room, but feel no pain whatsoever. The likely explanation is that if the brain indeed thought that the missing limb or the injury was highly threatening, you will be crouched, caring for your wound and will most likely succumb to your injuries. If you think about it, pain does not serve a protective purpose when survival is at stake.

Pain is so unique from other sensations such as touch, smell and taste that pain is defined as an ‘emotion or experience’. Pain, just like your emotions, is influenced by your thoughts, culture, beliefs and attitude.

In the 1950’s Henry Beecher, a military doctor in World War II, looked at the magnitude of injury and the morphine dose soldiers took to control pain. As expected, the greater the injury, the greater the morphine dose. And hence he concluded that there is no influence of your emotions and thinking on your pain. To apply these finding to civilians, he did the same study on civilians. And he found the same: the greater the injury, the greater the morphine. But there was one critical difference – for the same amount of tissue damage, the civilians took 3 times more morphine that the soldiers! How the heck is that possible?(9)

For a soldier, the injury meant he survived the war and he can recover and go back home. However, a civilian looked at the injuries from a completely different and negative perspective. For the civilian, the injury meant an awful situation which will dramatically change their life for the worse. Their emotions, attitudes and beliefs influenced how the brain perceived the threat level of the injury and modulated pain accordingly. It is now clear from brain imaging studies that that there is no single ‘pain centre in the brain’ as we used to believe. Many areas in the brain are actively involved in constructing and modulating this multisensory experience called pain (known as the Pain Neuromatrix). It is very appropriate to say that pain is an output constructed in the brain and not an input to the brain as we used to believe (10,11).

Now think how differently a football player and a stay-at- home mom experience their pain after a knee injury of similar magnitude?

3. Pain can change your nervous system

Acute pain due to broken bones, cuts, surgery, burns and such usually goes away when the underlying injury has been treated or healed. It might last for a few seconds, hours, weeks or, at the most, 3-6 months which is the time it takes to heal and remodel connective tissue. But in a sub-set of people, even after the tissues had enough time to heal, pain persists for years. Pain that lasts for more than 3-6 months is termed as chronic pain and has remained a mystery for many years.

We always believed that the brain and the nervous system cannot change.  But now we know that brain is plastic and can indeed change (the science of neuro-plasticity). This was only discovered a decade ago and it is one of the groundbreaking discoveries in the field of neuroscience.

We now know from imaging and animal studies that persistent pain or pain which lasts for months and years can change the pain pathways – peripheral receptors-spinal cord-brain(physically, functionally and chemically) to make it a lot more sensitive. And this hypersensitivity causes the brain to interpret anything related to those tissues to be highly threatening. Just like the concept, ‘the more your practice, the better you become at performing the skill’, the longer your pain persists, the more efficient the nervous system and the brain becomes in triggering and maintaining pain. Hence in chronic pain, pain has moved up to the nervous system and now has very little to do with the initial damage to the tissues that caused the pain (12,13,14). It is just the like the neurological adaptations in strength training that we always talk about.

So some times when folks are in chronic pain, they did not get hurt or they did not re-injure themselves as many think. It is just that your brain and nervous system has become so good at constructing pain at the slightest of triggers –even those that don’t cause damage. These triggers could be in the form of a slight pressure on the affected tissues or nearby tissues or just even the thought of the injury-causing incident. Chronic pain has been a mystery because we were just looking at the tissues and joints while ignoring the nervous system and the brain. But It is in the brain and the nervous system that the action happens!

Figure 2: The figure shows the old Cartesian model of pain and the new model which shows pain as a multisensory experience affected by both bottom-up and top-down inputs.

So what can you do about my pain?

The role of any pain treatment should be to lower the threatening inputs to the brain.  Just so that you know, we are talking about the treatment of chronic pain here and not acute pain (associated with tissue injury) which is pretty straightforward and well understood. What we are more concerned about is the chronic pain problem which has progressed beyond the normal healing timeframe.

Bottom-Up Approach (Nociceptive Mechanisms): This involves any treatments which lowers or inhibits the nociceptive signals (bottom) to the brain (hence called bottom-up approach). Most current pain therapies targeting the tissues and joints are based on this ‘bottom-up’ approach. A simple example would applying ice or heat to the damaged area. Another example would be lowering the weight for leg exercises if you have knee or low back pain (24).Mckenzie’s method, Postural correction, Sahrmann’s movement impairment syndrome,  Trigger Point therapy, ART, Functional Movement Screens and all come under this category.

But the problem with this ‘bottom up’ only approach is that the treatment is rationalized in a context which reinforces the belief that there is something wrong in their tissues and joints (and thereby raising the threat level) and may only bring temporary relief (25).

Top-Down Approach (Non-Nociceptive Mechanisms): This is done by educating the person about the physiology of pain, the role of brain in pain, and ”how pain does not mean harm” (hence called top-down approach).

If we explain pain based on our structural-pathology model, every time people feel pain they think they got hurt or re-injured themselves and naturally try to avoid pain-causing behaviors. This thinking process heightens the threat level in the brain leading to pain persistence (fear-avoidance belief model) (15,16).  The fear-avoidance model is now seen as a central mechanism of how acute pain turns into chronic pain. Pain education should make them understand that “pain does not mean harm” Most of our current treatments based on the structural-pathology model may provide temporary pain relief, but pain explained based on our current model only helps to heighten fear of pain and anxiety in the patient.

It has been shown in recent studies that teaching patients about modern pain biology can change beliefs and attitudes about pain and lower the pain sensitivity. Further, when education about pain physiology is included into physiotherapy treatment of patients with chronic pain, pain and disability are reduced (17,18,19).

If you are keeping up with me, it is more scientifically correct to include both methods.

Graded Exposure Approach or Activity: In this approach, the person is gradually exposed to feared activities without causing pain and thereby lowering the threat level in the brain. These feared activities could be imagined movements, exercise, or daily functions. Many researchers believe that a large part of pain relief seen with exercise and other rehabilitation methods is from lowering the threat level in the brain using the graded approach. So when you clients talk about how they have less pain after lifting weights, is it because they got stronger lifting weights or were they just gradually exposed in a graded manner to the threatening exercise or both?(20,21)

Can you give an example?

For example, Person A hurts his low back doing barbell squats. Now every time he tries to squat he feels pain in his low back. He works in the fitness field and strongly believes that the key to getting stronger and bigger is performing big exercises like the squat and deadlift.  And to make matters worse, he has read the works of Florence Kendall, Shirley Sahrmann, Gary Gray, Stuart McGill and other rehab experts who emphasizes the structural-pathology model and hence uses the ‘bottom-up approach’ in managing pain. All this has made him believe that there is something wrong in his joints and tissues. His beliefs, his attitude, and emotions have heightened the threat level in the brain and have made his nervous system a lot more sensitive to pain. He tries doing squats, but gets pain when he exceeds a certain weight. He has the pain now for more than 3-4 years and now he feels pain in the morning bending over the sink to brush his teeth, riding a bike or an elliptical or doing anything related to hips or low back for an extended period of time. Now he strongly believes his low back is very vulnerable to injury and he will never be able to squat or deadlift again.

But things are getting brighter. He reads how complicated pain can be, how pain is an experience constructed  in the brain and how  in chronic pain pain has moved up to the nervous system and the tissues maybe totally fine. He reads the book Explain Pain, works of Patrick Wall, Melzack, Louis Gifford, Lorimer Moseley, Waddell and learns a lot fromSomasimple.com discussions.

Top-Down Approach: He now clearly understands that the structural-pathology model, which relies solely on the ‘bottom-up’ approach is incomplete. Just by understanding the physiology of pain or the ‘top-down’ approach, his threat level has lowered in the brain. His nervous system is much less sensitive to pain and the brain finds no reason to induce pain because there is no threat and no action required. He feels much less pain now.

Bottom-Up Approach and Graded Exposure Method: He gradually starts incorporating deadlift and squats with light weights thereby lowering the nociceptive input (‘bottom-up approach’) and stays away from the pain flare up point. Within a few months, he is squatting and deadlifting with very little pain. The Person A is the author of the article.

Non-specific effects: Some of the pain relief with every pain treatment could also be attributed to the effects which are not specific to the treatment. These could include the person’s beliefs, expectations and experiences with other illnesses, previous use of the current treatment or other treatments, context and the interaction between the patient and the practitioner and so on (placebo effect). But, mind you, they all work by affecting how the brain perceives pain (22).

Every pain treatment out there, whether it is acupuncture, postural correction, movement dysfunctions, trigger point therapy, stretching, active release technique, manual therapy, McKenzie methods, meditation, yoga and so forth, works by the above mechanisms to affect the brain since the experience of pain comes from your brain and may have very little to do with eliminating the ‘pathology’ in the body as claimed. While many people do have “issues in the tissues”, that’s far from the only consideration.

I think we all can learn a lot from what Louis Gifford, a physical therapist and one of the leading authors in the field of pain, has to say about pain and dysfunction, “It is important to note that we are full of dysfunctions whether we are in pain or not. If we are in pain it is easy to find something wrong relevant to a precise tissue model but which may not be relevant at all to the patients state”(23).

Conclusion

The purpose of the article was to give a short introduction to the current understanding of the science of pain in a simple and non- technical manner. I really hope the article will provide a ray of hope (and direction) to people suffering from pain who have lost all their hope. I also hope that this article will help the fitness professionals understand what we were missing in our current approach to pain and how we can add the ‘top-down’ approach to make it more complete and scientific and thereby help our clients better.

Next time when you come across a client who complains about low back pain that he or she had for years, the two disc bulges seen on the scan, and how she or he has to be extremely careful not to hurt it again, what are you going to say?

Note: Please click the Recommended Reading (this will take you to a new page and then click on Recommended Reading again) for references and for other recommended resources on the topic. This will come as a PDF that provides links to all references.

Acknowledgement: Jason Silvernail DPT, DSc