Sunday, July 28, 2013

The Body-Self Neuromatrix

I am very happy to finally get to a discussion of the Body-Self Neuromatrix.  There is no doubt in my mind this will become an extremely important and influential theory.  I'll explain why in my summery.

This theory deserves our attention because it was developed by Ronald Melzac PhD.  Dr. Melzac established his credibility in the pain field as the developer of the Gate Control Theory.  The Gain Control Theory is now widely accepted and serves as the basis for most current research into pain.  That he has revolutionized such an important field not once but twice is very impressive.

To understand this theory I strongly suggest that the reader read a presentation by the author.

It is too important, and too complex, for me to adequately summarize, but I'll say the following:
It hypothesizes a widespread network of neurons that provide a scaffolding, or matrix.  One is born with the matrix, but it can be altered during ones life.  It involves parallel cyclical but communicating pathways.  It has several classes of inputs and outputs, but the function of the matrix is relatively simple.  It decides is homeostasis is lost.

As conceived by Melzac, there are three classes of inputs.  The first comes from the brain, and includes both tonic (slowly changing) and phasic inputs (more reactive).  Please see the chart below for examples.  The second group of inputs comes from the body.  The sub divisions are phasic cutaneous, tonic somatic, visceral inputs and visual, vestibular and other sensory inputs.  His third group of inputs is labeled "motivational-affective" and includes our endocrine milieu.
 Outputs include pain perception, action programs and stress-regulation programs.

One of the outputs discussed in the article I linked to above, but not listed in the diagram, is the suggestion that one of the outputs from the BSN goes to an area called the sentient neural hub.  Here, a continuous stream from the body-self neuromatrix is converted to continually changing stream of awareness.   Further, he suggests that the output from the BSN bifurcates, one goes to the sentient neural hub and another eventually activates spinal cord neurons for activity.

Among the wonderful attributes to this theory is that:

-it finally conceives of pain as a psychological phenomena that may or may not have a basis in the body: finally a theory describing the creation of pain that is congruent with the International Pain Societies definition of pain.

-the theory is not only a pain theory, but a theory of PTSD and anxiety as well.  We no longer have to wonder about the relationship of PTSD and pain: they are generated by the same mechanism.

-This theory continues the progression of pain theory from outside the body to now squarely in the central nervous system.

-We have, for the first time, a complete accounting for the factors that can increase our chances of having pain.  The BSN provides a basis upon which various medical and non medical interventions can be evaluated.  It provides a common ground for pain discussion between medical, surgical, psychological and non-medical interventions.  For the administrator, who much decide how to spend limited research funds, we now have a complete list of factors that cause chronic pain, PTSD and anxiety.  

-We also are forced by this model to acknowledge that pain does not exist in isolation.  The consequence of a loss of homeostasis are wide ranging.  With this model the clinician is forced to see that a chronic pain suffer is in danger in many different areas of his or her life.  We can see that every corner of a suffers life is at risk including his mental health, bone health, immune system, etc.  Now, more than ever, we can see the importance in aggressively helping those suffering with pain, PTSD, anxiety.

-The BSN theory also continues the historic trend from 'the sufferer as victim' to 'the sufferer as an active participant'.

Any good theory should raise questions and opportunities for further research.  This theory certainly does:

-Is it valid to conceive of the BSN as a machine which does not trigger an alarm till a certain threshold is met?
-The BSN is drawn fairly simply with inputs and outputs.  Can we add a concept of a positive feedback to the process?  That is, can the outputs from the BSN itself create conditions that irritate the BSN the next moment?
- Is it possible to calm, reassure or stabilize the BSN?  Can we make it more resistant to triggering the alarm?
- We have a list of inputs into the BSN.  These inputs can irritate, or promote the BSN to action.   Can these same inputs also stabilize the BSN?  It would seem to me that if we were interested in finding ways for humans to suffer less, research into this question should be a high priority.
- What input to the BSN is most influential?  Does the BSN preferentially look to one of these inputs to decide if homeostasis is lost?
-  Which of these inputs are most easily changed?
-  The BSN outputs vary in relative intensity.  But with chronic pain all outputs are stimulated.  Thus, chronic pain never occurs as an independent, isolated entity within the sufferer.  Is, then the concept of chronic pain too limiting?  Should it be obsolete?  What term shall we use for the sum the BSN outputs?

One of the great mistakes in modern medicine was to create and perpetuate the idea that the physician alone is responsible for providing health.   Chronic pain is the most dramatic example of this paternalism.  The result, all too often, is a patient addicted to our prescribed narcotics but still in pain.  The sufferers sole object in life is to constantly badger the physician for more pain medication, while in utter denial that they have any role in their pain.  If we have any chance to shift the responsibility to more balanced position, we must be able to give the patient the tools to help themselves.

The creation of pain is now in the brain.  The sufferer is now no longer a victim but an active participant.  We have a definition and a model of how pain (and PTSD) are created.  We have a list of opportunities to stabilize the BSN.  What tools can we give the patients to help themselves?

We have a huge cortex, a vast ability to think and a high degree of neuroplasticity.  We can leverage these tools to guide sufferers to relief.

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