SOME REFLECTIONS ON POLYVAGAL THEORY
The vagus nerve and polyvagal theory have over the last few years gained a large following. Deservedly so! Polyvagal theory and related practices give us valuable neuro-physiological and psychological information for our lives and can help specifically with bodymind therapy applications.
I’d like to cover a little about polyvagal theory and why understanding this part of our nervous system is in fact so fascinating and can be very helpful.
So first - required reading! An excellent introduction to this realm is “Accessing the Healing Power of the Vagus Nerve,” by Stanley Rosenberg. Rosenberg’s experiences in theatre, Rolfing, and cranio-sacral therapy give him unique qualifications to illuminate this topic.
Some essential points:
The old characterization of the autonomic nervous system as consisting just parasympathetic and sympathetic branches turns out to be an over-simplification. First, the characterization of these as fight-flight-freeze (sympathetic) or rest-digest (parasympathetic) gives us only a black-or-white picture of something that is more of a rainbow. We are always travelling somewhere along the full spectrum of autonomic response – at every moment we are modulating to smaller or bigger changes in our inner and outer environments. Just as an appropriate amount of heart-rate variability is a sign of heart health, so is the ability to move gracefully with autonomic-variability and appropriateness, through its full spectrum, is a sign of autonomic health.
In Polyvagal theory, originally proposed and researched by Dr. Steven Porges, the primary health goal is defined as “social engagement.”
The critical nerves whose functions most contribute to this are cranial nerves V, VII, IX, X (the vagus) and XI, all originating in the brain stem.
As opposed to just the previous binary picture of sympathetic/parasympathetic, we have now learned that each of these are involved:
1) The ventral branch of the vagus nerve
2) the dorsal branch of the vagus nerve
3) sympathetic activity from the spinal chain.
The vagus nerve is named for being a nerve that uniquely wanders throughout the body. In its vagaries, it particularly innervates the muscles of the throat and all the organs for respiration, circulation, digestion, and elimination. Interestingly, 80+% of its fibers are sensory, at most 20% are motor. Note how the nervous system prioritizes sensing.
The vagus nerve itself has two branches. The “sub-diaphragmatic,” dorsal branch of the vagus nerve primarily innervates the visceral organs below the respiratory diaphragm. The ventral “supra-diaphragmatic” branch primarily innervates organs above the respiratory diaphragm, including the heart and lungs.
The distinctions between the sympathetic activity of the spinal chain and the two branches of the vagus nerve are:
1) The sympathetic system is straightforwardly the fight or flight response
2) The dorsal branch of the vagal system is related to a kind of positive or negative shutdown.
3) The ventral branch (with the four other associated cranial nerves) is related to of social engagement.
None of these operate in isolation, so the interaction of the branches of the vagus nerve and the sympathetic system can give rise more or less to five states of being:
1) the social engagement system – the ventral vagus (with cranial nerves V, VII, IX and XI) gives rise to the experience of positive emotions and enjoyable interaction with others.
2) The spinal sympathetic chain activates when we feel threatened. This helps us “mobilize with fear” to defend ourselves by fighting or fleeing.
3) The dorsal branch may be activated when we face an overwhelming force. When there is no point to running away or fighting, then we “immobilize with fear.”
4) There is a hybrid state, “moblization without fear” in which the dorsal vagus supports the experience of intimacy, in which we slow down our physical activity, while the ventral vagus allows a feeling of safety.
5) the other hybrid state is one in which the ventral vagus and the sympathetic system combine during a friendly competition, like sports and other forms of play, in which fight or flight is combined with the feeling of safety.
How is all this helpful?
Polyvagal theory gives us the hope that finally we have a new and more accurate model for understanding bodymind health that can enable us much more effectively to intervene and treat physical and psychological conditions.
Now just to mention some of my thoughts so far of assigning too much importance to the polyvagal perspective:
1. The devaluing of experience.
We do not experience the vagal nerve. We experience life – stress, disappointment, joy, sadness, anger, movement, etc. The experiences of life should not be reduced to neurological descriptions.
2. The identification of energy with just the nervous system.
Energy, covers a much wider territory than just the vagus nerve, brain or the autonomic system. Centering overly much on the polyvagal system subjects us to what Alfred North Whitehead called the “fallacy of misplaced concreteness.”
3. The identification of brain with mind.
Just as energy is far vaster, though admittedly more vague-sounding, than just nervous system, the identification of brain with mind is an unfortunate over-simplification since “mind” and “responsiveness” is something we can say is evident cellularly throughout the person, not limited to the brain. Psyche is far vaster than brain.
The phenomenological approach to experience helps guide us to step back from excessively identifying with physiological descriptions. The experience of life is primary, not our descriptions of it, however compelling. However, with those caveats remembered, the insights of polyvagal theory and practices do cast a very useful light our experiences. The works of Stanley Rosenberg, Dr. Stephen Porges, Deb Dana and others are valuable contributions to human understanding.
THE VAGUS NERVE