Here’s how the brain connects to various parts of our body through the Vagus Nerve
The Vagus nerve is the tenth of twelve nerves running out of, and into, our brain.
Stephen Porges: neurology helping therapy
Why is Porges’ work so important? After all, the ‘flight/fight‘ response has been around for eons. Much was known about how it worked; how it was triggered and led us to recovery (if all went well). What Porges identified, however, was that the simple model of autonomic nervous system (ANS) overlooked some important features. The ANS plainly played a central role in initiating and sustaining the flight/fight response. It seemed as though a ‘pumping’ action kept us in balance.
If it helps, consider what Gregory Bateson has to say about change – half way down this page – “A man walking is never in balance, but always correcting for imbalance.”
My understanding is that Porges complicated our understanding of the ‘pumping’ action of the ANS by identifying the workings of the Vagus nerve, the second longest nerve in our body. He demonstrated that it was more than a single conduit. This nerve running the length of our upper body and comprised several off-shoots to face, upper body and ‘gut’, amongst others; hence, ‘Polyvagal‘, the many offshoots of the Vagus nerve.
More to the point, he concluded that its ‘parts’ emerged at different times in our evolution. Here is how Porges illustrates this point:
If the picture is readable, you will see the Geological eras listed on the left. Porges was talking about many millions of year’s evolution. During that process, the reptilian inheritance created a system whereby mammals, late arrivals on the scene, could be ‘immobilised without fear‘ , without risking fatally low rates of ingestion of oxygen.
That state of affairs – being immobilized without fear – rather assumes that an infant can adopt that strategy in a safe place. For this to happen, an infant needs a caretaker who can be trusted (we are very vulnerable, and much at risk when immobilized).
The Vagus Nerve evolved over millions of years
The later evolution of the Vagus nerve played a large part in helping mammals, including human beings, to detect situations in which they were safe. This process was helped by the evolution of the ventral Vagus nerve or ‘social engagement system‘ as Porges labels it. This helps humans find out who we can do business with.
BUT IT IS NOT IMPOSSIBLE, indeed, notions of ‘neuro-plasticity‘ suggest that it is feasible to adapt and redesign our neural pathways.