[this item is a raw copypaste of a fragment of Kym Ward's notes for her guided tour during Rotation II on July 27th, 2017, Barcelona]
What is the vagus nerve?
The vagus nerve conveys sensory information about the bodies organs to the central nervous system descend from cranium past the larynx, trachea and esophogus, to the diaphragm, gut and cervix
vagus nerve is responsible for transmitting involuntary signals - for heart rate, peristalsis (waving/ pushing food through intestines ) sweating, speech (via laryngeal nerve)
some people may cough when tickled in the ear – afferent nerve between the ear canal and meninges (men in dgez) which is membrane around the brain.
gag reflex, efferent nerves through pharynx & back of throat. Afferent nerve stimulation in the gut during gastroenteritus causes vomiting
When the vagus nerve is overstimulated due to certain triggers, such as the sight of blood or extreme emotional distress, trauma, menstruation, for example, (fight or flight) it can cause vagal syncope- in layman’s terms: fainting, which happens due to a sudden drop in blood pressure – which is caused by parasympathetic overcompensation to a strong sympathetic nervous system response.
Recent studies at Aarhus university – performing a vagotomy (cutting vagus nerve) suggest that parkinson’s begins in the gastrointestinal tract & spreads via vagus nerve to the brain.
And the reason I'm explaining the vagus nerve, is that I thought it might be nice to introduce Polyvagal theory into this inventory. Polyvagal theory is a phylogenetic theory – Phylogenetics being the study of evolutionary history of relationships amongst organisms/individuals/groups (done by phylogenetic inference using DNA sequencing, morphology (study of formal characteristics)
(check) Stephen Porges
So polyvagal theory deals with the autonomic function of behaviour, and was born, (literally) out of a relationship – Stephen Porges was the neurobiologist researching into the ANS via the vagus nerve – autonomic control system of the body that acts unconciously and regulates body function – heart rate/digestion/respiratory rate/urination/sexual arousal).
But his partner is C. Sue Carter – now director of The Kinsey Institute, who has spent her lifetimes research on the connection between oxytocin and social behavour. Oxytocin is a hormone, acts as neurotransmitter in the brain. Regulates social interaction sexual desire, maternal-infant bonding, empathy, generosity, orgasm. Hormone is stimulated during sex, birth & breastfeeding, hormone that underlies trust, but has a darker side to it – as it facillitates bonding but also favouritism (bias against).
C Sue carter - encouraged Porges to study social behaviour. As well as his research - sympathetic & parasympathetic nervous systems. – Older scientific explanations describe the sympathetic as "excitory" and the parasympathetic as "inhibitory" but this was changed due to the many exceptions found. A more modern characterization is that the sympathetic nervous system is a "quick response mobilizing system" and the parasympathetic is a "more slowly activated dampening system", but even this has exceptions, such as in sexual arousal and orgasm, wherein both play a role.
ANS is the Primary mechanism in control of the fight or flight response. – but what Porges was interested in, was another physiological reaction to stress, namely when the body shuts down, passes out, or in mental health - dissasociative states, this physiological immobilisation which was not acknowledged in psychaitry or psychology, doesn't correspond with fight or flight symptoms, and which can be attributed to primary or secondary complex traumas.
[[ Steven porges has a nice story which would fit into the possible bodies continuum, which is that he was going for an MRI scan for a brain condition, and experienced a kind of fainting panic attack, which he ]]
Polyvagal theory tells us lots of behaviours are functionally reflexive,
An example of immobilisation, according to Porges, is: when we look at language delays in children – by that I mean speech deficits, difficulties learning, you see that arising more in certain communiites or environments, especially those which are dangerous. Polyvagal theory would tell us that if your body is in a state of threat, this shifts the transfer function of signalling in the middle ear – which means you literally don’t hear the ends of words. You hear the start of the word but not the end. This has a phylogenesis in that the ear structure biased for moments of stress, to hear low frequencies, predator sounds, not higher frequency harmonics of voice.
So the theory proposes that there are 3 evolutionary phases in the vagus – primitive state which allows for digestion & immobilisation in threat.
sympathetic nervous system that can increase metabolism and mobilise body in fight or flight and 3rd stage, which is unique in mammals, which regulates heart and can create engagement or disengagement with the surrounding environment, and which in humans is regulates through the cranial nerves and facial muscles.
within the body, when the body reacts, we start to make hypothesis which may have nothing to do with the situation. What I like about polyvagal theory is that it takes seriously what we experience as emotional physical responses, that we are not aware of the cues which might cause this – for example construction work outside which has been registering in your brain (processes of neuroception) but not in your concious awareness, or the tone of a certain voice might put you on edge, but these environmental conditions are hijacking our behaviours by cues of bodily reaction.
Traumatic event is bad enough – but the consequences for the nervous system can be protracted.
The neural regulation below the diaphragm is different to regulation above Fight flight system is chest, shut down system is stomach/abdomen Many people who have sub-diaphragmatic surgery find that their sexual responses have changed this can be seen as a certain history of sexual trauma – sub-diaphramatic vagus has been recruited in defense when a person has immobilised, disasocciated, been restrained –
Part of the effect of being traumatised is an othering of respect for the body – people speak about their nervous system failing them, ( i.e. why did i let the abuse happen, why didnt i fight? body made the chioce ) for Porges, its important to first be appreaiative of what the body did before they making a narrative to excuse bodily reaction.
Linked with the face – cues from face/gesture/intentionality of facial gesture allow us to hear the human voice more accurately, seems to ethically follow that responsibility of co-regulatory relationship is to keep autonomic nervous system out of states of defense and immobilisation Safety love trust Keep out of states of defense – facilitate social bond also - health growth and restoration
universities are environments of evaluation –puts us chronically on defense – watched. The current academic/disciplinary model is – if you feel too secure, you wont do your work, but model is wrong – if you feel secure you can be bold creative – society says if youre scared you work harder, all that really means is work is more movement.
Safety allows emerging properties to occur (aesthetics/spiritualty) and allows us to learn and retain information because we are not competing with levels of threat.
So Porges & Carter's coupling of neurobiology with social engagement theory also seems to provide an argument in response to disciplinary systems: they will prevent thinking.
“The nervous system of social behavoiur is the nervous system of health growth and restoration”
"The removal of threat is not the same as knowing you are safe" (slice that!) Beyond holism.