THE HUMAN GROWING EDGE

This quiet research work on the third and myelinated vagal nerve turns out to be a vivid account of evolution.  First it's necessary to define "phylum."

"Mammals, including humans, are part of the phylum chordata, which also includes fishes, amphibians, reptiles, and birds. As you can see that's a very broad category. Phylum comes above class and below kingdom in the biological classification system."  "Chordata" is about backbones, which means when we tried to organize categories, that's what impressed us.   The Euro work done in the name of science often is dependent on "boxes," categories.  It becomes an obsession and interferes with reality.  We like them to stay permanent. 

"There are 36 recognized animal phyla, of which but nine (Mollusca, Porifera, Cnidaria, Platyhelminthes, Nematoda, Annelida, Arthropoda, Echinodermata, and Chordata) contain the vast majority of described, extant species."  Chordata are vertebrates, but you'd be hard pressed to name them all or even recognize them.

• The 8 animal phyla. Porifera, cnidaria, platyhelminthes, annelids, molluscs, arthropods, echinoderms, and vertebrates.
• Vertebrates. - backbone. ...
• Echinoderms. - spiny skin. ...
• Arthropods. - exoskeleton made of chitin. ...
• Molluscs. - many make a shell that is either 2 parts, (clams) or 1 part, (conch). ...
• Annelids. ...
• Platyhelminthes. ...
• Auricles.

Traditional classification of vertebrates

• Class Agnatha (jawless fishes)
• Class Chondrichthyes (cartilaginous fishes)
• Class Osteichthyes (bony fishes)
• Class Amphibia (amphibians)
• Class Reptilia (reptiles)
• Class Aves (birds)
• Class Mammalia (mammals)

We are more conscious of five of them we call mammals, birds, fish, reptiles, amphibians.  The work of Stephen Porges and his team has traced the anatomical evolutionary crossover between reptiles and mammals when mammals added and developed the third vagal nerve system.

Four principles that provide a basis for testing of hypotheses relating specific neural mechanisms to social engagement, fight–flight, and death-feigning behaviors:

• There is a phylogenetic (that is, an evolved change across phylums from reptile to mammal) shift in the regulation of the heart from endocrine communication (sending molecules in the blood stream to control the body) to unmyelinated nerves and finally to myelinated nerves (fast, multiple electrochemical code).
• There is a development of opposing neural mechanisms of excitation and inhibition to provide rapid regulation of graded metabolic output.
• A face–heart connection evolved as source nuclei of vagal pathways shifted ventrally from the older dorsal motor nucleus to the nucleus ambiguus. This resulted in an anatomical and neurophysiological linkage between neural regulation of the heart via the myelinated vagus and the special visceral efferent pathways that regulate the striated muscles of the face and head, forming an integrated social engagement system 
• (With increased cortical development, the cortex exhibits greater control over the brainstem via direct (eg, corticobulbar) and indirect (eg, corticoreticular) neural pathways originating in motor cortex and terminating in the source nuclei of the myelinated motor nerves emerging from the brainstem (eg, specifi c neural pathways embedded within cranial nerves V, VII, IX, X, and XI), controlling visceromotor structures (ie, heart, bronchi) as well as somatomotor structures (muscles of the face and head).

Most animals don't show a lot of expression on their faces.  Dogs come the closest to making faces since they are so closely connected to humans.  It would be interesting to see how that changed their autonomic cranial nerves.  

Expression comes from ears, but also by licking, controlled by that same specific nerve.  Mammal licking enables birth, expresses connection, serves practical purposes like cleaning, and is connected both to vocalization and eating, as it is for people.  (Foods that require licking, like ice cream or suckers, have a special appeal.)  Eating and talking, like important leaders sharing meals or the Judaic discussion meals that became Communion, are key to human relationships.

Neuroception is a new word meant to describe the awareness of people to their environment, particularly in the context of safety.  When the place and time seem safe, the "more primitive limbic structures" are suppressed and a person can be more cooperative, creative, and progressive.  Safety might not be the result of conscious thought.

But here's the payoff:

"To effectively switch from defensive to social engagement strategies, the mammalian nervous system needs to perform two important adaptive tasks: (1) assess risk, and (2) if the environment is perceived as safe, inhibit the more primitive limbic structures that control fight, flight, or freeze behaviors.

"Any stimulus that has the potential for increasing an organism's experience of safety has the potential of recruiting the evolutionarily more advanced neural circuits that support the prosocial behaviors of the social engagement system."

"Neuroception might be triggered by feature detectors involving areas of temporal cortex that communicate with the central nucleus of the amygdala and the periaqueductal gray, since limbic reactivity is modulated by temporal cortex responses to the intention of voices, faces, and hand movements. Thus, the neuroception of familiar individuals and individuals with appropriately prosodic voices and warm, expressive faces translates into a social interaction promoting a sense of safety."

"The features of risk in the environment do not solely drive neuroception. Afferent (going to the brain) feedback from the viscera provides a major mediator of the accessibility of prosocial circuits associated with social engagement behaviors. For example, the polyvagal theory predicts that states of mobilization would compromise our ability to detect positive social cues. Functionally, visceral states color our perception of objects and others."

Your guts change the way you see things.  Happy tummies make the world look good.

So humans are meant to work in groups, for which they need the perception of safety and probably a common goal.  This is what managers are supposed to be watching -- not the profit line, which will be better anyway if a team is working together.  But the real importance of grasping this physiological work is that it makes further evolution of abilities and achievements much more possible, even likely.  This is the human "growing edge."