Vagal Brake: A Mechanism to Contain Emotional Reactivity
The evolving mutation from reptiles to mammals included a shift in the control of the heart rate to a myelinated branch of the vagus nerve. (Remember that some consider the lungs and heart to be one organ.) The effect was something like replacing an on/off switch with a rheostat, capable of modulation on a spectrum and much more nimble.
"The myelinated vagus provided a mechanism to rapidly and efficiently regulate visceral organs to foster calm prosocial behaviors and psychological and physical health."
"The hypothalamic pituitary adrenal (HPA) axis is our central stress response system. The HPA axis is an eloquent and very-dynamic intertwining of the central nervous system and endocrine system. ... The HPA axis is responsible for the neuroendocrine adaptation component of the stress response." Oversimplifying, the HPA axis is felt by a person as emotion and can "catch" emotion from others. It is involved with what Porges kindly calls "defensive" behavior, but what I might call "bar fight berzerk." That is, emotion out of control, sometimes a result of trauma. When the proper vagus control works, the raging person can be talked down. Possibly even calm down.
In less dramatic circumstances, using breathing and other ways to calm down, self control allows the person to keep relating to other people instead of smashing the bar mirrors. Script writers have picked up on this and we often hear characters advise each other to "take deep breaths" in a crisis. Schools have not provided instruction for this in a systematic way.
The HPA axis is an endocrine system, working by global molecules that circulate through the whole body. The organs operate with unmyelinated nerves normally, but also can be reached by the vagal myelinated and brain-connected messages. I don't know of studies, but suspect that poor mental and nutritional factors can suppress the action of the vagal system. Not only does this suppress the survival value for individuals but also it means that evolution in those settings will favor violence as a means of survival.
The Face-Heart Connection: The Emergence of the Social Engagement System
Only recently have we admitted the importance and operations of emotion, much less felt it was the business of formal education, but plainly our society is in dire need of this knowledge in a divided and frustrated world.
https://www.wsj.com/articles/how-to-manage-your-coronavirus-anxiety-11583424434?mod=wsjtwittertest19
This is an attempt to engage the brain by describing steps that are being taken to address coronavirus. Of course there is anxiety and it is justified, but it helps to know what is being done. Keeping people in the dark makes them paranoid, separated from each other, and emotionally vulnerable.
The regulation by the rheostat-like myelinated vagal motor pathways acts like a cardiac pacemaker. It's called the "sino-atrial node" and it can calm and actually reduce stress by dampening the HPA axis, reducing cortisol, and reducing inflammation by modulating cytokines.
In addition to these effects, part of the myelinated vagus connects to the muscles of the face and head. I read about Lucy Maude Montgomery's face being paralyzed on one side when she was overwhelmed by her duties. When I was interning with the Hartford UU Church and preaching there for the first time, my face went out of control, jerking and grimacing. The same thing happened once when I officiated at a particularly moving wedding. It's called "Bell's Palsy." I had a very weak version. It can be recognized by others and calmed if they "keep their cool." This is the evolved advantage.
The expression on one's face indicates to others whether it is safe to approach or whether it would be better to keep some distance until what is happening is more clear. In the best of circumstances, the person who is not affected can be reassuring by talking or even singing as a mother sings to a child. I once knew a high school counselor who had been arrested in the Detroit riots and when held in a jail full of raging people, but he restored some calm by promoting singing. Since most of the people were Black with a tradition of group singing to stay calm and in control, it worked pretty well
"Social communication and the ability to co-regulate another, via reciprocal social engagement systems, leads to a sense of connectedness, which is a defining feature of the human experience". As well as human compassion. I would add that it also works on domestic and esp. companion mammals like dogs or horses, who can also calm and comfort humans.
The importance of the polyvagal theory is that it shows that physiological state IS mood and emotion and is bidirectionally integrated with brain along with viscera. "As individuals change their facial expressions, the intonation of their voices, the pattern in which they are breathing, and the shifts of their posture, they are also changing their physiology." This is what actors know and do, particularly those working with the "method" which uses memories to recapture physiological states that can subtly show in performance. The roots of memory physiology go back to the original care giver, usually the mother, who works to prevent panic in an infant whose brain is not old enough to provide self-talk or control the HPA function. The caregiver supplies the calming rituals: rocking, singing, babytalk, kissing, feeding, cleaning. In adulthood these persist, often connected to sex, like showering or bathing together. Maybe formally as in tantric sex.
When the castle or convent is under attack, one goes to the chapel to pray in order to stay calm. I don't know what it means that so many young people are comforted by loud, rhythmic, defiant music. Maybe that reflects the households that produced them, so it's familiar. Or maybe the ritual of the young is dependent on extreme movement and sensory challenge like "raves".
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