The Cor-Kinetic “Movement Neuromatix”- A multifactoral approach to movement.

The ‘movement neuromatrix’ model is designed to show our movement as more than just the mechanical operation of bones, joints and muscles. All of the inputs we have listed in our model below have an affect on how our brain recognizes and responds to movement.

The movement of the body should be seen as the physical expression of a neurological process, a brain ‘output’. The graphic in the middle of the diagram below represents the movement ‘output’ and is influenced by the surrounding ‘inputs’. Often we see movement purely as an ‘output’ of the body rather than being influenced by the many ‘inputs’ that the brain receives and uses to determine our motor or movement ‘output’.

It has been influenced by Melzack’s “neuromatrix” which introduced a multi factorial model for pain and the many contributing ‘inputs’ that shape the pain experience. One of the largest departures from traditional views of pain, is that in the ‘neuromatrix’ pain is an ‘output’ of the brain rather than than simply an ‘input’ or signal from the body.

Melzack describes this:

I have labeled the entire network, whose spatial distribution and synaptic links are initially determined genetically and are later sculpted by sensory inputs, as a neuromatrix”

Everything that flows through our ‘neuromatrix’ is shaped by it. ‘Inputs’ only trigger ‘neurosignatures’ or ‘output’ patterns from the ‘neuromatrix’ rather than the ‘input’ creating the ‘neurosignature’ at source An example of this is pain being created in the periphery and transported to the brain and ‘neuromatrix’ rather than sensory input triggering a pain “neurosignature’ and resultant pain ‘output’ from the ‘neuromatrix’. Other ‘inputs’ to the ‘neuromatrix’ such as stress levels can influence and modulate the pain ‘neurosignature’ ‘output’. We could also have a pain ‘output’ in lieu of sensory ‘input’ from tissue and structure.

Our “movement neuromatrix” is designed to highlight one single output of the neuromatrix, movement. It is not a revision, adaptation or a replacement. More a focus and opinion on one of the many outputs from the ‘neuromatrix’. The addition of ‘movement’ to the title is to highlight this focus.

In fact we could even see the process behind  the ‘movement output’ as the reverse of how we perceive the pain process. Pain is mainly seen as an ‘input’ when in reality it maybe more of an ‘output’. Movement is often seen as an ‘output’ ignoring the many ‘inputs’ and contributing factors.

We believe movement is similarly influenced by a multitude of contributing factors that are modulated by the brain to produce our unique movements.

neuromatrix(1)

This model works on the premise the brain is the controlling factor in our movement. In fact our brain is able to rewire itself, strengthening the connections it uses regularly and eroding the ones it doesn’t.  This is a process described as neural pruning.

Axon branches more active in releasing neurotransmitters persist at specific neuromuscular sites, whereas less active axon branches retract, resulting in the canonical elimination of polyneuronal  innervation

Jackie Yuanyaun Hau et al.

This is a fancy way of saying, “use it or lose it” in terms of our neural connections, one of the major principles of neuroscience and neuroplasticity.

This rewiring is a based on a multiple inputs that include our memories, structure, sensory systems, vitality and environment that create our unique ‘movement fingerprint’ or neural circuitry that defines an individuals movement potential. This all happens in the cerebral cortex where the sensory and motor systems, which rely on each other for successful movement, live. These cortical areas are now being seen as vital to understanding both our movement and pain.

Without constant and accurate feedback from our touch maps, our motor maps can’t do their job. And so a feedback loop of mutual degradation is set up: Your touch map worsens so your motor map worsens, which worsens your touch map more”

The body has a mind of its own. Sandra and Matthew Blakeslee.

One aspect of the changes that occur when pain persists is that the proprioceptive representation of the painful body part in primary sensory cortex changes. This may have implications for motor control because these representations are the maps that the brain uses to plan and execute movement. If the map of a body part becomes inaccurate, then motor control may be compromised – it is known that experimental disruption of cortical proprioceptive maps disrupts motor planning

Lorimer Moseley, Professor of Clinical Neurosciences and Chair in Physiotherapy, School of Health Sciences, University of South Australia.

Our movement is made up of our previous experiences collected over our lifetime, both internal and external. To see the body as a purely mechanical structure misses the great depth of experiences that constitutes the ‘movement neuromatrix’ and the role the brain, nervous system and memory play in our movement. We are able to now understand the influence of our previous movement problems on our future problems at a motor control level by looking at the brain and its various inputs. Research has shown that a big predictor of future injury is past injury!

“Adaptation to pain has many short term benefits but with potential long term consequences

Hodges 2011

Our daily demands and postures, previous movement problems and sensory inputs are major players in dictating what happens in our future movement. Previous pain causes changes within the brain to our motor and sensory cortex that then controls our movement potential. Getting out of pain is the gold standard of rehabilitation but rarely is previous movement assessed or restored, often we take a symptom or pain reduction approach. This altered movement can then potentially create movement issues and pain at a local and global level at a later date. This means a move away from a more biomechanical or postural biased model that may look at specific structures, such as the feet, to blame for the problems the body may experience. The available research does not consistently support specific pathomechanics in relation to the pain experienced.

“Although pain provides a potent stimulus to change the movement strategy to protect the painful or injured part, resolution of pain or injury does not necessarily provide a stimulus to return to the initial pattern”

 Hodges 2011

In fact pain can be the body’s opinion of a tissues health based on all of the information contained within the neuromatrix rather than actual damage.

This means that assessing in a low threshold way, such as a treatment table, may not allow you to create the right environmental factors to find the movement problems associated with an injury or restriction.

Our Cor-Kinetic SAID principle of assessment tells us that the body will give us a Specific Answer to an Imposed Demand. As the demand of the assessment changes so will the response to the demand. This can be especially important with elite level athletes and the more athletic population in general.

We believe the brain works on a model of:

Patterns – Memory recognition of situation

Perception – Interpretation of sensory feedback

Prediction – Response-Including reduced movement or pain

Only by feeding the body the right patterns of sensory information, which comes from movements authentic to peoples movement needs, can be expect to get the true response or prediction from the body that would happen away from an assessment/treatment situation in their functional situations. Problems can often be simply an opinion or prediction of what is going to happen in response to a motor command/ planning or movement situation. Much of what happens in terms of sensory processing is simply an interpretation or perception that can change on a minute-by-minute basis. Nerve signals are amplified or attenuated at a central level according to others factors included within the “movement neuromatrix”

Pain is an opinion on the organism’s state of health rather than a mere reflective response to an injury. There is no direct hotline from pain receptors to ‘pain centers’ in the brain”

 VS Ramachandran

Our sensory systems are also key players in our ‘movement neuromatrix’

All of our senses have an impact on the way that we move to successfully process the large volume of available information our body needs to navigate our environment. Mismatches in this sensory information can cause sub optimal movement and pain. The sensory system is not just our movement information but also, and possibly more importantly, our visual and vestibular systems.

“it remains possible that in a sensitized or disrupted neurological system such as in neuropathic pain, sensory-motor incongruence might contribute to, or maintain, pain”

Moseley and Flor 2012

Our internal health including stress hormone levels, diet, hydration and breathing will also affect our movement and pain levels. These are also included with the ‘movement neuromatrix’ when considering movement ability.

Only by interacting with the ‘movement neuromatrix’ through effective movement, sensory and health based assessment within an authentic environment can we truly understand the individual and their movement potential.

References

Blakeslee S, The body has a mind of its own, Random house, Sept 2008

Hodges P Walker K, Moving differently in pain, PAIN 152 (2011) S90–S98

Jackie Yuanyuan Hau et al, “Regulation of axon growth in vivo by activity based competition” Nature, 2005 Vol. 434 21

Kandel E et al, Principles of Neural science, fifth edition, November 2012

Lederman E, The fall of the postural–structural–biomechanical model in manual and physical therapies: Exemplified by lower back pain, CPDO Online Journal (2010), March, p1-14. http://www.cpdo.net

Melzack R, Pain and neuromatrix in the brain, J Dent educ, 2001 Dec, 65(12):1378-82.

Moseley G, Flor H, Targeting cortical representations in the treatment of chronic pain, Neurorehabilitation and neural repair, XX (X) 1-7

Moseley L et al, Cortical changes in chronic low back pain: Current state of the art
and implications for clinical practice, 3rd International conference on movement dysfunction 2009

Moseley L, A pain neuromatrix approach to patients with chronic pain, Manual therapy 2003, 8(3) 130-140

Ramachandran VS et al, Touching the phantom limb. Nature. 1995;377:489-490.

Ramachandran VS and Blakeslee S, Phantoms in the brain, New York: William Morrow, 1998

Posted in Uncategorized | 3 Comments

Can functional movement be too much?

I thought I would have a bit of a Jerry Maguire moment with my latest blog post!

Over the last few months I have certainly gone through a period of change with regards to how I understand the human body. Anybody who regularly reads my blog may have sensed that! I have begun to appreciate the brain as the command centre for all that we do, moving away from a more functional/biomechanical approach I had previously. This has been facilitated by some pioneering characters around me who I am thankful to for opening my eyes, even if it can feel sometimes that they don’t want others to come along for the ride! I have certainly suffered my own bouts of cognitive dissonance along the way.

My overiding end game will always be to get people back to moving optimally (for them) in their function. Many of my movement assessments have remained consistent, such as gait, as I am still interested in how they perform movements that relate to the movements they want to perform in related positions relative to the things that act on them e.g. gravity, ground reaction, mass and momentum! It is not so much the biomechanics I am assessing more the brains ability to control the meaty bits (muscle) rather than the mechanical motion of the bones, joints and muscles.

I now realise however that many things can also impact on movement such as the visual and vestibular system (if these bits don’t go, the body won’t either!) emotion and memory of previous injury. Pain also has changed for me, it is no longer simply a result of poor biomechanical motion but instead interlinked with many factors in the brain that can often have nothing to do with our structure or feedback systems at all. But this is not the time or place to go into that now.

One point is that in some circles people are starting to see pain as multi-faceted with many contributing factors. Melzack’ s Neuromatrix theory (1999) has thrown a new light on pain and pain science. Movement is similarly multi factorial and we are now starting to see the contributing factors as a “movement neuromatrix” with many of the contributing factors coming from outside of the biomechanical realm. We are seeking to simply outline these factors that would influence a “movement neuromatrix”, both internal and external.

Screen Shot 2013-02-24 at 14.04.24(Melzack 1999)

A new way of thinking has allowed me to understand why a functional/biomechanical approach has allowed me to achieve success in the past and also explains some of my failures as well.

One conclusion is that for some people complex functional movement can be far to much for their bodies to handle. At best we maybe ineffective but could we be making things worse?

We know that if we give someone a movement task to achieve they will find a way to achieve it with the movement ability that they have. Often times by using the movement pathways that are available to them and that they use regularly. By feeding them these “functional” patterns we may not have changed anything, merely reenforced the movement they had previously. The more complex a movement involving many joints the more ability of the body to use different bits it can use rather than the target joints we would like it to use more of. If we do succeed in making it look better through hands on techniques or coaching the movement does it stay this way when we are left to our own devices without outside help? Does the person have the hardware (brain and neuron connections) to run the software (movement pattern) successfully? An analogy I like to use is that of trying to run a PS3 disc on a tape computer from the 80’s!

A purely feedback based approach dictates that the hardware (brain) is set. But the exciting and fast moving world of neuroscience tells us differently.

ps3

spectrum

Our hardware relies on a few principles of neuroplasticity (the ability of the brain to change). This is that “neurons that fire together, wire together” and the principle of “use it or lose it” Simply put this means that neurons associated with movements we use often will strengthen their connections with the other associated neurons and neurons associated with movements we don’t lose their connection strength. This is a process known as neural pruning. These neurons will be associated with firing up the muscles at the right time to create the reactions we want. These neural associations also create the neural representations of body parts we have in our cerebral cortex that have been referred to as maps. Our movement is governed by our maps. If our map is poor then our movement will also be poor. Our map is regulated by the way we move and also then dictates the way we move. If it is poor, blurry or smudged (Blakeslee 2010, Butler 2006), the terms some have used to described eroded maps, then we create a cycle of faulty movement that is hard to break. The maps have also been associated with chronic pain through the incongruence between predicted and actual propriceptive feedback and an altered body schema (Harris 1999, Mcabe et al 2005). Mismatching feedback from our senses when integrated, such as in the cerebellum, has been hypothesised by many as a cause of chronic pain.

An example I have used previously is that of the flat foot, the map for the foot may not have strong connections associated with creating an arch (if you feel this is creating a problem!). Helping some one do this hands on or with complex exercise may not be enough to change the hardware and may explain why the predominant foot posture prevails. We can create movements that facilitate a supination reaction in the foot but do we do it within the parameters of the function? We know that external tibial rotation creates supination of the foot in gait. If I have to create much more external rotation than would ever happen in gait to create supination, either through hands on manipulation or exercise, will that have a crossover into my desired function e.g. gait? Will it become the predominant motor pattern within the brain when in subconscious function? Maybe not if we don’t have the right sensory or motor maps to understand and create it.

We may have to use a more targeted methods in specific areas away from function to increase the sensory feedback and therefore motor control. It may not look like function but may have a functional response within the hardware (brain) that allows us to use complex software (authentic functional patterns) and get the desired outcomes. In fact an inability to perform specific targeted movements at a joint may be an indication of sensory and motor changes through neuroplasticity within the sensory motor cortex (Moseley 2009, Moseley and Luomajoki 2010) Will the body choose to use areas it cannot control effectively when faced with a complex task, such as an integrated functional movement, if it has the ability to compensate through many joints it can use to achieve the task?

We must not confuse increasing the hardware through joint motion by just applying a specific pattern to a joint. Our motor control is a general ability to perform many motions not an ability to perform a clinical and contrived motion or “corrective exercise” at a joint as directed by some practitioners as being indicative of good function or problematic if not performed correctly. Our focused joint mobility exercises should look at increasing our feedback to the somatosensory areas which will help increase our cortical mapping through neuroplastic rewiring. The key is in the reintegration to the gross functional motor pattern. Putting the joint back into a functional context with the rest of the body to allow it to play its full roll in global range of motion and force dissipation and creation. This must also be done at differing loads, speeds, movement variations and levels of stability. We know that the body may not choose to use movement it has available if unable to control it (motion and stability). Again this is a skill that can be enhanced through movement education in an authentic context, such as a functional position.

Many solely brain based approaches may assume that once we have the hardware we can run any software. But we still have to apply, learn and refine that software program to make it better and that’s where functional movement comes into its own!

As always this is just my opinion on the way certain things may work within the brain and body. Certainly not evidence based in a traditional sense. We must remember however that evidenced based is based on evidence for the questions we have asked, not the ones we haven’t yet and is biased by the view of those asking the questions. If that is based on a traditional anatomical understanding of the body then the answers will be related to the bias!

References

Blakeslee S & M, The body has a mind of its own, Random house, Sept 2008

Butler D et al, The sensitive nervous system, NOI group publications, 2006

Doidge N, The brain that changes itself, Penguin group, January 2008

Forencich Frank, Topiary physiology, Go Animal

Harris AJ. Cortical origin of pathological pain. Lancet 1999;354(9188):1464e6.

Luomajoki H Moseley GL, Tactile acuity and lumbopelvic motor control in patients with back pain and healthy controls, BR J Sport MED 2011 Apr;45(5):437-40

Melzack R, Pain and the neuromatrix in the brain, Journal of dental education, volume 65 No12

Moseley G, Flor H, Targeting cortical representations in the treatment of chronic pain, Neurorehabilitation and neural repair, XX (X) 1-7

Moseley G, et al, Cortical changes in lower back pain:current state of the art and implications for clinical practice, Manual therapy 16 (2011) 15-20

Moseley G L, A pain neuromatrix approach to patients with chronic pain, Manual therapy (2003) 8(3), 130-140

McCabe CS, Haigh RC, Halligan PW, Blake DR. Simulating sensory-motor incongruence in healthy volunteers: implications for a cortical model of pain. Rheumatology 2005a;44(4)

McCabe CS, Haigh RC, Halligan PW, Blake DR. Re: sensory-motor incongruence and reports of ‘pain’, by GL Moseley and SC Gandevia. Rheumatology 2005b;44:1083e5. Rheumatology 2006; 45(5)

McCabe CS, Haigh RC, Ring EFJ, Halligan PW, Wall PD, Blake DR. A controlled pilot study of the utility of mirror visual feedback in the treatment of complex regional pain syndrome (type 1). Rheumatology 2003;42 (1)

Posted in Uncategorized | Tagged , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , | 4 Comments

No motor learning attached to walking, really??

It would seem my previous blog has generated some discussion on whether walking is simply an innate skill or there is motor learning attached to the process. For me it quite simple, but hey I am a simple guy.

Firstly we must not confuse learning with being taught. No one teaches you how to walk. But it is a self-driven learning process.

In fact is it driven by a desire to walk? The sensory motor stage of development as described by Piaget between 0-2 years involves learning by trial and error. As discussed in the previous blog failure is biological necessity.

Piaget also talks about goal-orientated behavior to bring about a desired result when we get to around 12 months. Right around the time we start to look to walk!

Well walking is just that, a goal orientated behavior. It is a better way to move around the world, just like those we see around us. It maybe an innate desire, who knows, but it is not a desire realized without the need for motor learning.

Lets look at what innate means:

Innate:

1. Possessed at birth; inborn.

2. Possessed as an essential characteristic; inherent.

3. Of or produced by the mind rather than learned through experience

There has always been a discussion about whether walking is innate or not. So I suppose it is a matter of opinion. But not a fact.

So do we possess the ability to walk at birth? Well no, or we would walk out of the womb or soon after! Fish are born with the ability to swim. Humans are not born with the ability to walk.

Our reflex ability’s are the sucking reflex , clasping reflex, Moro reflex, Babinski reflex and Root reflex. We do have a stepping reflex but this is not walking which comes with motor learning. This is a simple reflexive action rather than a complex and coordinated skill.

Learning to walk IS a complex skill. In fact all movement is a skill that has motor learning periods associated to it. Motor learning is important and nowhere more so than in performance training where the skills being learned become exceptionally complex. But the same rules of motor learning still apply. People may be better at complex skill initially because they have previously chunked general movement patterns associated with that skill in previous motor learning experiences but generally the more reps they do the better they get (although not always!)

Although there may be elements of walking that are pre-encoded as research as suggests, even blind children learn to walk, and demonstrated by basic reflexes such as the stepping reflex. It is not a purely innate skill such as breathing or swallowing which we are able to do as soon as we are born however. Blind children will still have to go through the same motor learning process as their sighted peers if not more so. The environment we learn and experience will also play a part. Think of feral children who move like the animals that have adopted them.

Baby

The fact is we do not just get up and walk. We go through stages of motor learning to get there. Even without the rolling and crawling (which also involve simple reflexive components) that comes before, we first practice standing and swaying finding our balance, then take one of two steps and fall. We get up and try again practicing the complex motor skills associated with locomotion. Next time we make more steps.

Even the observation of people walking is involved with the motor learning process. Imitation through mirror neurons is vital to human development. This process I believe shows we are learning through experience, which by definition would not make it purely innate.

Associated reflexes maybe hardwired but the gross skill certainly is not just there and available as it later in our lives after we have been through this process. That’s why we start of waddling and swaying and then refining until we are more proficient at the skill. We do this through a learning process. A motor learning process.

We make neural connections and then myelinate the pathways to improve the firing rate and strength of the motor pattern. This is Hebbian learning. “neurons that fire together, wire together” So we practice like any learner of a skill that is new. This is not a purely innate or reflex based scenario.

The first stage of motor learning is the memory encoding or cognitive stage where we are cognitively aware of the task that needs to be performed. The performer may be more concerned with what to do rather than how to do it.

This maybe described as a desire to walk. This maybe something we are born with. But certainly does not replace the motor learning stage.

In the associative stage the participant is now concerned with performing and refining the skill. The conscious decisions become more automatic and can concentrate more on the doing of the task.

The autonomous stage is when the action being performed is automatic. Walking without conscious thought is a good example of this.

This process is vital for efficient operation in the brain. Moving without conscious effort decreases the need for conscious attention on the task. This means the task can be moved back down the brain from the frontal executive areas associated with conscious thought and put into action in older areas such as the cerebellum and spinal cord.

Looking at reflex’s does not give any credit to the brain and its role in everything we do and how we learn. It is a simple and limited way to understand the body.  A bit like just seeing muscles as simple reactors to bone motion which gives no credibility to the understanding of motor patterns, their development or neuroplasticity as a concept. If you are being taught this way are you being kept in the dark?

Posted in Uncategorized | 2 Comments

Muscle isolation? Is that how you learned to move?

This is just a quick blog that was inspired by taking my son to the park yesterday. It is more anecdotal than scientific but something that I wanted to get across.

My son is developing so fast at the moment and it is amazing to watch. He is now 16 months and the two biggest areas I see his development in are movement and speech. It got me thinking about how we correct peoples movement problems and teach them to move better.

So many times we hear about a movement dysfunction being blamed on a muscle ‘not firing’ at the right intensity or at the wrong time or instead of another that should be firing. We lie people down and prod and poke them, cajole their poor muscles into firing. Ask them to make strange and alien movements they have never made before in the name of ‘firing a muscle’ This term, or the term “muscle firing pattern’ are some of the most searched terms on google with regards to my blog when I look at the stats. This makes me ask, is this how we learned to move in the first place?

muscle firing

Well, not really. These ‘muscle firing’ exercises are very specific. One thing I have noticed about my sons development, both in terms of speech and movement, is that it is pretty non specific. He is learning to make general sounds and movements that he can start to build more complex words out of or more complex movements from. He is building a broad vocabulary of generalized movement that he will store away for his lifetime to refine and refer back to, to hone and increase. We cannot isolate a muscle, we know that. But we can isolate a movement, a hip abduction for example, which is still a co-ordinated activation of muscles around a joint. This is something I have never seen my son do however. He never lies on his side and abducts his leg, he never makes glute bridges to fire up his butt muscles. He never gets in a half squat position and moves sideways. He may be an exception but I am not sure I have seen other babies do it either (although my experience is limited in this respect)

So the question is, why if we never learned to move like that, why are we relearning to move like that?

My son is building a broad vocabulary by interacting with the world, performing relevant functional tasks (many pointless right now I may add!) that will serve him well in the future. He learns to roll over, then crawl, then walk and finally run. He squats down in a million different ways, he learns push himself up and climb, again non contrived and with countless variables. He picks things up and I can see his fine motor control developing as he fumbles with tasks we would find simple to perform. Slowly these things improve and get more complex, quicker and less thoughtful. How much of this relates back to how we now try to correct movement through perfect, contrived, non functional and isolated muscle activation. Well not so much! He is learning by playing and exploring the variables. Our brains love novel movements, especially when the vocabulary of movement becomes reduced by our limited variability and repetitive daily lives. All of this is creating neuroplastic changes in his brain that he will continue to developed on a neuronal level for the rest of his life. Neurons that fire together, wire together. The less neurons you have working together in a movement pattern then the less will fire together and wire together. By attempting to isolate muscles, more likely movements though, we are creating disjointed motor patterns, not fluid and variable motor learning environments.

baby

Do we sometimes have problems though not because of the lack of specific motion but instead because we have lost the broad base or vocabulary of movement that we learned early in our lives. Our movement capabilities become eroded by what we do everyday. Sitting down, contrived and rigid exercise, specific muscle activation exercises. We don’t explore our movement potential through play and variety the way we used to earlier in our existence. Neuroplastic change is not always positive. Another neuro saying is ‘use it  or lose it’, this describes neuronal connections that unused will wither and die. These can be those involved with our ability to move like we did when we were children or adolescents when we explored the boundaries of our movement much more.

In fact we learn by failure. Failure is a biological necessity we all go through in the learning process. Not perfect movements straight away, first time. Learning new movements can be something we stop doing as we get older and set into our movement routines. We feel if we do not have perfect form then it is not worth doing an exercise or movement. Think about learning any sport, mostly in the beginning we are pretty bad and persevere. We do not ‘activate’ the perfect motor pattern or muscle and away we go. We start off being bad and getting better as we learn the associated movements.

Have we become to clever for our own good? Our knowledge of the anatomy of the body has become vast. We have dissected bodies and created big books with wonderful illustrations that tell us the precise location and action of all the muscles. Which in itself is a great human achievement. We have clinical practice and evidence based research to guide what we do. Has this all missed the point slightly though. If we are not going to look back at how we learn to guide our motor learning in the future then evolution has failed. Nature has computed the variables already. She has had billions of years of practice developing the best ways to create functional human beings. We seem to have kind of become counter intuitive delving deeper and deeper into the complexity of the body rather than embracing its spirit and multi-faceted movement ability in the three dimensional environment we live in. Looking back at when we seem to have the least of our problems and when most of us moved best without the aches and pains. This is not saying we should squat like babies etc etc. Simply looking back to our motor learning period that forms the basis of our movement and how we do it!

Not a hugely scientific blog I am afraid. Just some thoughts.

Posted in Uncategorized | Tagged , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , | 3 Comments

The brain, movement and pain! Part two.

In the first part of this 3 part series we looked at patterns and how the brain recognizes patterns of information to then be able to recall or auto-associate a response from stored memory.

This is our model of

  • Patterns
  • PERCEPTION
  • Prediction

In this second part we are going to look at perception and the systems that send this sensory information and how it is centrally processed. We compare the stored pattern with the sensory pattern flowing into the brain to then be able to make a prediction on the likely outcome of executing the stored pattern. The cerebellum is vital to this process. One of its major roles is matching the senses with the stored patterns and help executing and adjusting the associated motor programs. Our perception helps us to compare the stored pattern with the actual situation that is occurring.

The sensory information includes muscle length and tension, joint position, pressure, vibration and temperature and pain signals. We also receive sensory information from the visual and vestibular systems.

We refer to it as perception rather than information because the way that we perceive this information wildly differs from one person to the next. In fact the same person can perceive this information differently one hour to the next. A signal that may cause pain when you feel tired and sensitive may not bother you when rested and strong. This is because this information is centrally processed and modulated by our ‘neuromatrix’ as we first discussed in part one of the blog. Our energy levels, stress levels, health, and emotional state affect this modulation. You name it and it will affect your central processing of information.

perception

Our sensory pathways are recursive meaning the higher centers in the brain modify and shape the incoming flow of sensory information.  Our perception of the world is shaped by us internally as well as us externally.  Much the same as the information we read is shaped by our political and moral beliefs. Two people can interpret the same information differently based on their internal modulation. Perception is not a direct record of the world around us but a subjective interpretation. German philosopher Kant referred to these brain properties as ‘a prioriknowledge.

The brain responds to the perceived, not the actual reality”

Moseley and Flor 2012

Our main sensory sources of information from the body are the ascending somatosensory pathways that flow up the spinal cord into the cerebellum and Cerebral cortex.

We have signals that transmit information to conscious and subconscious areas of the brain. The higher sensory cortex receives conscious information that needs to be taken notice of such as an itch we need to scratch and pain (also projected to the insular and cingulate cortexes)

pathway

The cerebellum receives subconscious information that allows us to move effectively without the need for conscious thought.

These sensory pathways from the body include:

The Dorsal column medial leminiscus pathway or DCML transmits conscious proprioceptive information such as touch from the body up into the sensory cortex via thalamus.

The spinocerebellar tracts four divisions transmit subconscious proprioceptive information from the body up into the cerebellum.

The anteriolateral Spinothalamic tract transmits temperature and pain information to the thalamus and then higher up to various cortical areas.

 The cerebellum

 The cerebellum is an amazing area that comprises 10% of brain size but contains over 50% of the total neurons. This alone tells you its importance.

The Cerebellum matches intended movement or patterns with sensory information to help create a prediction of the outcome and then relays this information to the brain stem and motor cortex. In this way it is able to react to the variations in patterns through the sensory systems and vital to the model of patterns, perception and prediction in the brain.

The Cerebellum compares internal feedback information that reports intended movement with external information that reports the actual motion. It is constantly integrating information from various senses, comparing them to stored patterns and helping us adjust to perform a task. It is essential in executing coordinated motor control tasks both in terms of planning and modification during execution.  It is in communication (via thalamus) with the higher brain structures of the cerebral cortex that allow it to compare our movement with and then adapt many of the stored patterns. The constant loop of sensory and motor information between the cortex and cerebellum is vital for our movement success.

cerebellum

The cerebellum is divided into 3 functional divisions:

Vestibulocerebellum – Regulates balance and eye movements

Receives input from visual cortex and vestibular nuclei.

Helps with important reflexes such as the vestibulo ocular reflex . The vestibulo ocular reflex is characterized by compensatory eye movement induced by head movements. As the head is generally constantly moving along with the movement of the body, this reflex is particularly important.

Spinocerebellum – Body and limb movements

Receives information mainly from somatosensory receptors via spinal cord

The cerebellum actually learns patterns to be able to provide feed forward motor control to regulate motion. This anticipatory ability (even in before sensory feedback occurs) allows smooth and accurate motion to occur. This must be a learnt behavior assigned to a motor pattern as we build a vocabulary of movement and based on previous sensory feedback rather than instantaneous feedback.

Cerebrocerebellum – Movement planning.

Receives information from cerebral cortex via pontine neclei of the pons.

The cerebrocerebellum is involved in high-level internal feedback circuit dealing with motor planning and regulating cortical motor patterns.

cerebellum 3

To understand our clients/patients movement we also have to understand how the different sensory pathways influence the execution of our movement.

This has to include the visual and vestibular systems as well as the proprioceptive as they play a major role in the sensory matching within the cerebellum. We will discuss later in the blog the implications of sensory mismatch. All of our senses including smell and hearing will have implications for movement as they help us form a representation of the world around us.

The sensory system does display a hierarchy of importance with the visual system often biasing information from others sources. In essence that means the stretch and strengthen model of affecting tissue maybe redundant in the face of higher dysfunctions within the sensory system hierarchy. ‘Stretching out’ a muscle such as a tight pectoral may be futile. Massage, needling, releasing and manipulation as well. The muscles postural state/position that is dominated by an ocular imbalance will prevail in the long term until it is rectified. Up to 70% of postural control comes from the eyes and motor pattern and visual information are integrated within the brain.

Such things are not controlled at a ‘local’ level of bone, joint or muscle movement.  The anticipatory cerebella activity influencing muscles at a local level to maintain a predominant posture may be too strong to overcome without addressing the sensory cause at a higher level.

Ocular weaknesses and lack of control that affects our field of vision or eye dominance will directly limit our ability to move. The brain suppresses information from the weaker or less dominant eye (unless short sighted, go figure?) leading to a reduced field of vision and a dominant head, body posture and movement patterns to accommodate the stronger eye. This suppression can happen if the images from each eye don’t match, one is blurry for example, the brain may choose to suppress the information from it. Changes at a muscular level will not change this postural motor program within the brain that is dominated by the eyes.  A shift in approach maybe needed with long term postural problems that do not respond to localized (muscle level) treatment. This can also create intra system sensory mismatch. Sensory mismatch is something we will discuss later in the blog.

eye

Much of our so-called proprioceptive training is really visual, vestibular and proprioceptive as we are probably using the first two systems for balance and stability. We tend not to look at the visual and vestibular system when we look at movement dysfunction or ‘stability’ however.

Any of our sensory systems will impact on our movement potential in terms of muscular length and force that are controlled by brain based motor patterns.

Our assessment and treatment instead focuses on localized and contrived muscle activation in non functional positions (prone) that does not take into account the pattern recall, perception and prediction model of the brains role in movement and pain.

Neuroplasticity

 In fact over time sensory information can alter the way we move. Rather than remaining physiologically set, as was the prevalent understanding of the brain, the brain is a plastic and changeable area, both in terms of physical structure and functional organization.

As we learn and experience new things the brain is able to make new neural connections and strengthen existing ones involved within a new physical skill or even non physically such as learning a new language.

This follows the “neurons that fire together wire together” principle from the first part of this blog. The neurons involved in the new patterns strengthen their connections plastically changing the functional organization of the brain.

This also helps us understand the neurological principle of “use it or lose it” or “neurons that fire apart, wire apart”

Connections or patterns that we don’t use, well simply, we lose or are eroded! That’s why when you perform a skill you have not performed for a while; you probably will not be as good at it as when you are regularly practicing.

“Axon branches more active in releasing neurotransmitters persist at specific neuromuscular sites, whereas less active axon branches retract, resulting in the canonical elimination of polyneuronal  innervation”

Jackie Yuanyaun Hau et al.

Simply put less active axon branches die off and more active ones persist and grow stronger. In this way we refine our neural capability for efficiency and therefore increased survival and performance potential. This process is modulated by what we do on a daily basis.

This has huge implications for movement and posture. If we do not use certain movements of the body then we will get worse at using them in the future. The neural connections and associated patterns with these movements diminish or are overtaken by stronger patterns.

A good example would be a flat foot. The neurons associated with the motor pattern of creating an arch within the foot will not be as strongly connected as they would with a foot that regularly creates an arch and has neurons that fire together to create this reaction. In this case it would be move it or lose it!

Flat foot

So the neural hardware required to run this particular software or movement program is not as strong as it should be. Simply applying a software/movement pattern to the hardware without trying to upgrade the hardware may mean the movement will not run as smoothly as you desire.  Simple feedback based exercises or manipulations may not address the hardware issues associated with creating neuro plastic change.

In fact cortical changes have been shown to be stronger when associated with learning about the experience and not just the sensory feedback involved. Cortical representations can increase two to threefold within 1-2 days of the new sensory motor skill being first acquired (Merzenich and Blake 2002-2006)

The process of changing the hardware maybe a far more concentrated, cognitive and directed approach than subconsciously driven exercise, stretching or hands on techniques. The change of a long held postural or movement pattern can be a challenging process that requires a level of cognitive engagement. To to break the predominant pattern you have to be aware enough not to slip back into it!

Cortical maps

Within our cerebral cortex we have cortical representations of areas of our body. This cortical representation is a network of neurons that can be in many areas of the brain and is associated is with an area of the body. The most famously understood is in the somatosensory/motor areas.

So for the foot we have a foot area and for the hand a hand area! Sensory information from the body is projected to the area that it is associated with. Dr Penfield way back in the 1930’s described these areas as the Homunculus or little man when he first mapped the cortical areas.

homunculus

hom

A famous study by Merzernich in 1984 mapped a monkey’s hand before amputating the third finger and then mapping the brain again 62 days later.

He found that the second and fourth finger had invaded the area formally associated with the third finger.  A case of use it or lose it!

This has huge implications for conditions such as phantom limb pain as explored by the great neuroscientist Ramashandran. Even though the body part has been amputated the cortical representation of the body part remains. Adjacent areas that are somatopically-organized invade this remaining area. This means the wrist representation is next to the forearm, forearm next to elbow etc. So the arm representation that remains, even though it has physically been amputated below the elbow, is receiving sensory feedback from the elbow that has invaded the cortical space formerly occupied by the arms sensory feedback!

Flor et al (1997) found with chronic low back pain patients, the cortical back representation in the somatosensory cortex (S1) had invaded the lower leg representation and the extent of this expansion was closely associated with the chronicity of the pain.

sensory cortex

This sensory change also has implications for our ability to move. Our sensory information flows through our sensory areas before going to our motor areas. In this way what we are sensing directly affects the way we move. Equally the way we move affects our sensory areas. This again can be a case of move it or lose it.

Thomas Hanna coined the phrase ‘Sensory motor amnesia‘ A condition in which we lose the ability to voluntarily move certain parts of our body in the ways that we want to. Often they stay ‘stuck’ in an unchanging posture either unable to relax or contract and create change in our postural position. This can come about through habitual movements and postural positions and persistent protective motor patterns after an injury. The associated neural pathways to change the posture or move these parts of our body will fade with inactivity.

Without constant and accurate feedback from our touch maps, our motor maps can’t do their job. And so a feedback loop of mutual degradation is set up: Your touch map worsens so your motor map worsens, which worsens your touch map more”

 The body has a mind of its own. Sandra and Matthew Blakeslee.

 Both David Butler and Dr Cobb of Z health have cited this blurring or smudging of the map as a cause of, or as a result of pain. The brain can perceive the inaccurate map as a ‘threat’ to the system as reduced map clarity will have an impact in cases of sensory mismatching.

 This remodeling also happens in the face of pain. Previous injury and pain therefore affects future movement through neuroplasticity.  Australian neuroscientist Lorimer Moseley has been researching the sensory cortex changes in chronic pain patients and how this affects motor control.

One aspect of the changes that occur when pain persists is that the proprioceptive representation of the painful body part in primary sensory cortex changes. This may have implications for motor control because these representations are the maps that the brain uses to plan and execute movement. If the map of a body part becomes inaccurate, then motor control may be compromised – it is known that experimental disruption of cortical proprioceptive maps disrupts motor planning

Lorimer Moseley, Professor of Clinical Neurosciences and Chair in Physiotherapy, School of Health Sciences, University of South Australia.

The implications of this are important because we all pick up injuries both minor and major in our lifetime that will erode and remodel our movement ability at a cortical level. Rehabilitation from injury generally involves getting rid of the pain response and not restoring any movement deficits or neuroplastic changes associated with the injury. This can lead to chronic injury/pain situations. Localized protective motor patterns originally induced during a pain response may persist even though pain has ceased. This can also alter gross movement patterns and affect other areas within a function related kinetic chain.

Sensory motor mismatch has also been attributed to pain. We can relate this back to the input mechanisms in the cerebellum discussed earlier. McCabe (2005) examined Ramashandran’s (1995) informal implication of pain in the absence of tissue damage being caused by incongruence between motor intention and proprioceptive feedback. A mirror was used to disrupt motor command and proprioceptive feedback in this study. Surely this would also involve the visual system, which must be taken into consideration when discussing sensory and motor congruency and looking at the cerebellar inputs and outputs.

Dr Cobb from Z health also discusses sensory mismatching as a cause of threat and pain to the body. For example if we have an eye dominance that creates a tilted and rotated head position it maybe that the visual system information is now at odds with the vestibular information when integrated in the cerebellum. The head position assumed to be in neutral from the visual system is not in vestibular neutral (because the head is tilted) The information from each source is conflicting. This can lead to inter sensory mismatching and a ‘threatened’ state in the brain.

it remains possible that in a sensitized or disrupted neurological system such as in neuropathic pain, sensory-motor incongruence might contribute to, or maintain, pain

Moseley and Flor 2012

Pain is a complex subject however, not just linked to proprioceptive or nociceptive feedback. There are many brain-based reasons for pain beyond the scope of this fairly simple blog and many other areas of the brain to explore in relation to pain. (disclaimer over!) One such reason is the apparent threat of damage to bodily tissues without input from nociceptive fibres.

In the next part we will look at the prediction the brain makes based on the stored pattern and the perception of sensory information it receives. This prediction may result in pain even in the absence of any tissue damage. In this way the body can predict a threat to the tissue even in situations when it may not be warranted. We will also look at the central sensitization of the processing of sensory information. Signals that may not have previously exceeded the threshold for threat or pain will can be interpreted as thus as the central threshold decreases.

References

Jackie Yuanyuan Hau et al, “Regulation of axon growth in vivo by activity based competition” Nature, 2005 Vol. 434 21

Forencich Frank, Topiary physiology, Go Animal

Moseley G, Flor H, Targeting cortical representations in the treatment of chronic pain, Neurorehabilitation and neural repair, XX (X) 1-7

Moseley L et al, Cortical changes in chronic low back pain: Current state of the art
and implications for clinical practice, 3rd International conference on movement dysfunction 2009

Doidge N, The brain that changes itself, Penguin group, January 2008

S Blakeslee, The body has a mind of its own, Random house, Sept 2008

Kandel E et al, Principles of Neural science, fifth edition, November 2012

R and I Phase Courses, Z health.

Butler D et al, The sensitive nervous system, NOI group publications, 2006

Bryan L et al, The sensorimotor system, Part 1: The physiological basis of functional joint stability, Journal of athletic training, 2002;37(1) 71-79

Ramachandran VS et al, Touching the phantom limb. Nature. 1995;377:489-490.

Posted in Uncategorized | Tagged , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , | 1 Comment

The brain, movement and pain! Part one.

The brain and its role in movement and pain is taking a much larger role in what we do at Cor-kinetic. Rather than just seeing the body as feeding back to the brain on a mechanical level we are starting to understand the brains active role in everything we do.

brain

In this series of 3 blog posts we want to give a little insight into the way that we see the brain working on a conceptual level at Cor-Kinetic. It must be stressed this is not a scientific paper or evidence based research. Instead it is more of a paradigm about the way it may work on a global level and our opinion of this.

This model of the brain and the way that it stores patterns, recalls them, matches them with feedback and finally predicts an outcome forms the basis of what we do. It guides our assessments, techniques and movement coaching. In fact the prediction may not always be the one we want or expect, especially in the case of pain. It may even be the anticipation or contemplation of a neural pattern can cause a poor movement or pain based prediction without any feedback from the body needed.

We will outline our model of:

  • Pattern
  • Perception
  • Prediction

Over the next few weeks we shall publish one blog for each part of the model. These blogs are going to be pretty conceptual and based on the learning into the brain that we have done up to this point and our interpretation of how this may then fit into a useable but mainly theoretical model! We can guarantee that some will agree and some not.

 Patterns

One of the underpinning concepts behind how the brain works is that the brain is a pattern recogniser. It auto-associates stored neural patterns within the brain with the patterns that it experiences constantly during our interaction with the world. These neural patterns are a collection of neurons that fire when we see certain things or move in certain ways or even feel emotions. These neural patterns form the basis of who we are and what we do based on what we have experienced. These stored patterns allow us to subconsciously perform everyday tasks or sit up and take notice when encountering new and novel patterns that are out of our ordinary, or expected experiences ascend up the cortical hierarchy. These novel patterns can end in frustration when attempting to learn a new skill (or un-stored pattern) for example.

In fact it may be we have patterns that fire in anticipation of a sensory event rather than as a reaction. This truly is the definition of prediction and may be heavily associated with the pain response as we will discuss in a later blog.

As these collection of neurons fire together the synaptic connections get stronger. The famous neuroscience quote goes “neurons that fire together, wire together” This concept is derived from Hebbian theory, named after Canadian neuropsychologist Donald Hebb. These neurons can be movement based or vision based or taste, smell you name it. In fact all these sensory elements may fire at the same time to create a neuronal ‘signature’. Ronald Melzack coined the phrase ‘the neuromatrix’ to describe the spatial distribution and synaptic connections neuroplastically shaped by sensory input during our lifetime. Melzack talks about a ‘neurosignature’ imparted on all nerve impulse patterns that flow through our particular ‘neuromatrix’.

neural pattern

We also have smaller neural ‘signatures’ or patterns for specific events such as movement, speech etc. Lorimer Moseley describes these patterns as ‘neurotags’ Many neurons are associated with more than one pattern or ‘tag’. This means that if the member cells of a ‘neurotag’ are also associated with a pain response then when these member cells fire in response to another ‘neurotag’ then they can also trigger a pain response in the other pattern or ‘tag’.  One of Moseley’s specialties is back pain. His concept (or my interpretation!) is that neurons involved with your back pain may also be involved in thinking about back pain, therefore the thought of back pain or even the back also triggers the pain even in lieu of movement. We also know that visualizing a movement pattern also causes the same pattern of neurons to fire in the brain as the actual movement so we can start to see the interconnectedness on a neural level.

It may also be that these neural ‘signatures’ or patterns are emotional or behavioral in nature. Negative thinking is even a pattern, this becomes a problem when it is the predominant pattern the brain uses when dealing with emotion or situations it is interpreting.  It could explain why we hold and retain emotions and views such as prejudice.

Jeff Hawkins in his book “On intelligence” talks about this auto association of patterns being because the brain, specifically the cerebral or as Hawkins describes it the‘neo’ cortex, and its neurons are actually pretty slow compared to transistors. 200 calculations per second perhaps rather than the billion that a computer can do.

Computers work by carrying out a constant stream of calculations such set out by the forerunner of the CPU the original Turing machines of the great English mathematician Alan Turing. He figures heavily in one of my favourite books, the epic Cryptanomicon by Neal Stephenson. It may take millions of calculations to perform a task if we were to calculate all the variables all the time. Instead of this the brain is able to auto associate a stored pattern from memory, created over years of practice, to perform the task. This evolution of a pattern through countless repetition allows it to be good or bad. In fact we even have another mechanism called invariant representation to deal with the minute variations in patterns from the stored ones that we hold to deal with the enormous amount of variation the world is constantly throwing at us.

circuit

As we develop we learn a vocabulary of movement. If I throw my son a ball at the age of 15 months it will just bounce off him (as it does regularly). He has not developed the neural patterns involved with recognizing an approaching ball, the concept of catching it or the associated motor patterns to perform this skill.

As he learns this he will refine the skill of catching until he can effortlessly pluck the ball from the air without any need for conscious thought. This is pretty much how we learn and perform all motor skills. Auto associating them with previous stored memories and refining them through repetition.

Mirror neurons are vital for learning of new patterns especially in the young. We often learn through imitation of our parents and those around us. I feel this has huge ramifications for how we teach movement.

In fact the more we use a neural circuit the more white matter (mixture of fat and protein) called myeline encase the axons that connect the neurons involved. This insulates the axon allowing impulses to travel much quicker, up to 100 times quicker, than uninsulated fibres. Coupled with this increased signal velocity we also see decreased refractory time (the waiting time between one signal and next) so the ability of the brain soars at a particular skill in the face of practice and reinforcement.  We see this in the proposed 10,000hr rule for expertise.

myelin

So these patterns become literally etched into our brain. A good example of this is some of the simple study’s that have been carried out on the reaction times of sportsmen. In one case the best table tennis player in the squad had by far the worst reactions of any player and even the team manager when his reactions were tested away from the skill of table tennis. What he did have however was more experience and this means that he had better stored and refined patterns. He did not react to the ball better but his movement vocabulary was larger and he had recognized the pattern of the ball so many times he knew where to put his bat and which motor pattern to recall quicker than those around him. In sport the reaction times can be minute, is this pattern recognition and recall rather than the reaction or computation the key to success?

Hawkins describes the process:

  • The Neocortex stores sequences of patterns
  • The Neocortex recalls patterns auto-associatively
  • The Neocortex stores patterns in an invariant form

So what is invariance? Well within a computer we see 100% accuracy, complete fidelity. A computer would recognize a set pattern and store it that way. In fact discrepancies cause serious problems within computers. A byte corrupted or out-of-place can wreak havoc in the digital domain.

Our world is beset by variation, we constantly see the same faces in an ever-changing context such as lighting for example. Experiments have shown computers to struggle with this scenario. To a computer this variation in pixels would mean it would struggle to associate it with the stored pattern. This means you would never recognize the pretty girl you met in the bar in the street, if serendipity were to play its hand favorably.

I maybe thrown a tennis ball or a football or even a pair of socks rolled up as a ball and have to use the same stored catch pattern but in a different context and with slight variations. The concept and invariant representation of ball and catch is stable even though the physical scenario or object changes.

The same would be true of table tennis. The angle, trajectory, velocity and spin may all be different but we still hit the ball through the recall of a motor pattern, just slightly differently according to the variation in the balls movement.

desmond

This ability to store important relationships and patterns independent of detail is hugely important. The same pattern of neurons will fire in the visual areas of the cortex when you look at your friend regardless of the context or lighting you are in.

Our movement is one of the areas that the feeds the brain with specific patterns. Equally our movement is influenced by the patterns that we hold within our brain influenced by many other parts of the ‘neuromatrix’. In my humble opinion the actual movement of bones on a biomechanical level is less important than the neural feedback pattern from the afferent tissues this bone motion creates to match with and create a prediction from at a central level. More important are assessments to find out why the brain efferently restricts movement of the tissues it controls and which biomechanical or non biomechanical patterns (E.g. vision, vestibular or previous pain) and subsequent protective prediction this may arise from.

So what does this all mean on a practical level? Well if you want to assess the brain and bodies reaction to a particular pattern then you have to in some way feed into the auto-associated pattern involved. On a movement level are the patterns of movement that cause a triggering of the neurons involved in specific movement interactions and possibly pain authentic. You can only assess the response by coming close to what auto associates the pattern even taking into account invariant representation in my opinion.

Does bed based assessment of movement for example allow us to assess the brains prediction to a movement situation without the specific perception of the  neural ‘signature’ or pattern required from the feedback mechanism? The reduced information from say the vestibular and proprioceptive systems in the absence of gravity may be very likely to change the pattern. This could me that pain is reduced because the pattern has changed but will come back again when having to deal with the original pattern. This is something we see a lot of with traditional bed based therapy’s that temporarily relieve pain. Are the pain patterns or signature driven at a higher level of pre-motor planning for example or a sensory mismatch of the systems above spinal cord level that integrate in the cerebellum? Have we assessed these as well as just the passive motion of bones, joints and soft tissue?

Understanding neural patterns helps us to understand why movement skill is such a highly specific process that takes countless repetitions to perfect in terms of invariant association to a skill situation and a successful and consistent response.

In part 2 we will look at Perception and how the brain uses feedback from the somatosensory systems including proprioceptive, visual and vestibular to help turn the stored pattern into an actual prediction of what is going to happen. How this feedback maybe centrally processed in a problematic way such as during central sensitivity and how pain can influence the sensory and motor cortex to rewire through neuroplasticity and change the way we feel and our subsequent motor control and movement.

Posted in Uncategorized | Tagged , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , | 1 Comment

Muscle activation – Are muscles simply reactors to bone and joint motion?

So I have seen various variations on Gary Gray’s view that muscles are reactors. I think this is spot on. Muscles ARE reactors.

I think what Gary meant by this was that generally we see muscles as concentric force producers. Actually during movement we tend to need to decelerate motion by eccentric contraction first. Think walking first we flex to attenuate gravity, ground reaction forces, mass and momentum before creating force to move. So we are reacting to forces acting on the body before we create concentric force.

Some people have added variations on this theme talking about bones and joints feeling movement and muscles being dictated to by to this motion.

At Cor-Kinetic we feel that view is not the full picture. Muscles are reactors, but not to bones and joints but to the brain. We must remember movement is not just a feedback model but also involves feed-forward too.

Bone and associated joint movement will create mechanoreceptor afferent (feedback) signals to the brain based on this information the brain may choose to allow the muscles to lengthen, shorten or even stay the same length. So in fact the muscles may dictate to the bones, something we see all the time when people lack ROM! Muscles can choose to limit the deceleration, in the face of force acting on the body, we go through rather than just dumbly reacting.

The muscle spindles are not just feedback mechanisms but also feed-forward (efferent). The intrafusal fibre tension is regulated feed-forward from the brain. This means that if spindle tension changes efferently then that will change the spindle gain and affect the afferent feedback information (change of length and rate of change of length). The brain can change the sensitivity of the information that it receives back from itself. Amazing.

spindle

We see this constant stiffness adjustment as we run on different surfaces. The leg spring stiffness remains constant although the ground stiffness changes. This means that we create changes in muscle tone through efferent changes in spindle gain even though the biomechanical bone motion remains fairly constant. Farley has done some great research in this area. Click here for research paper.

 So the brain will dictate the muscular “reaction” to the bone and joint motion, not simply react by moving. In fact we know that muscle activation patterns changes with pain not simply in response to bone motion. In face we develop protective motor patterns to deal with injury and many times these are not full rehabed back to pre injury movement capacity. In fact over a lifetime, especially if we are involved in sport, we pick up numerous injuries that change our motor patterns and create our individual movement signature.

“Although pain provides a potent stimulus to change the movement strategy to protect the painful or injured part, resolution of pain or injury does not necessarily provide a stimulus to return to the initial pattern”

 Hodges 2011

Great work into pain and changes in our motor control has been done by Hodges click here for his “moving differently in pain paper”

“Adaptation to pain has many short term benefits but with potential long term consequences

Hodges 2011

So we can use our feed-forward control such as changes in spindle gain to protect against unwanted bone motion as perceived by the brain. Do simple changes in bone motion (especially passively created by external sources such as practitioners hands) create long term adaptations in motor patterns? In my experience not always.

We also know pain is a reaction to a set of patterns in the brain, whether this is a motor pattern or emotional or chemical pattern. It can even just be through the firing of a neuron associated with pain and an area of the body as in the ‘neurotag’ concept from Lorimer Moseley. This could even be through simply talking about pain or an area of the body associated with chronic pain.

We can force bones to create a reaction in a muscle. This may not happen when the body has to control its own movement based on its stored motor patterns and previous experiences that are much more complex than simple biomechanical movements.

The body is one massive feedback loop. Systems higher up in the brain beyond the spinal cord and cerebellum will also dictate how our muscles react. These can be Ocular, Vestibular, emotion, pain perception and previously stored patterns and responses.

brain

One last thought. If the body was simply biomechanical and force based model then everybody with structural problems would be in pain and everybody who has a “good” structure would not be in pain. We know this is not true. People achieve amazing things and pain-free lives with academically terrible foot types and huge leg length discrepancies. Research supports this.

So what mediates their pain and performance responses? Why the brain of course. So what that means is for someone with a small leg length difference that maybe the cause of their pain, for someone else with a huge LLD it may not be the cause of their pain. Someone’s individual brain and CNS response will dictate this. This maybe why so many scientific study’s are inconclusive on many treatment types and structural abnormalities effect on the body. “Does not always” does not “mean will not ever” Can we have any definitive in the body? So the evidence based approach may disregard the right approach for the right person. It just means nothing is right for everybody all the time. But we knew that right? That’s why some of the people I respect so much have such a multi faceted approach to treating the body and learning from a broad range of experts in different fields.

This means that people who tell you that your LLD IS the cause of your pain COULD be right 50% of the time or a certain foot type WILL cause you back pain maybe also right. That fascia is the key to everything POSSIBLY MAYBE right some of the time. But behind their certainty may not be anything real but just personal experience clouded by bias. As all of us are clouded by, myself included.

As the famous Betrand Russell quote goes “The trouble with the world is the stupid are cocksure and the intelligent are full of doubt” I doubt think this is literally true because people are sure AND intelligent. We just need to be more full of doubt in our methodology and be aware of other influences on the body and its pain and performance.

Another approach maybe to start to look at the influential mechanisms in the brain as well and improve the brains confidence and control of areas that it may perceive as a “hazard” to the system. This could happen at a local joint level or a higher cortical level or a bit of both!

Not the most scientific blog but thanks for reading.

Check out http://www.cor-kinetic.com for more information on what we do and our courses.

Posted in Uncategorized | Tagged , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , | 1 Comment