Development of the Nervous System, Part 1

Photo by Loic Leray on Unsplash

Becoming a human being is a curious thing.  What part makes us human?  Our ability to think?  To relate and to love? Before we can do either of those things, we must first learn to BE, to exist.

Our brains and capabilities build a layer at a time. An unborn baby doesn’t learn arithmetic tables, nor does s/he get upset at not getting a cookie.  His main learning is that he exists, and in a body growing at a phenomenal rate.

He won’t pay full attention to anything else if his poorly functioning body is distracting him with notifications of processes which should be automatic.  So before the Baby Einstein and reassurance of how precious s/he is (though both of those will be welcome later on), first comes learning to exist in the body, and maintain existence with absolute minimal attention from the conscious mind.

Learning all of this is more complex than it might seem.  The complex system of systems –



nutrient intake, absorption, and waste disposal (gastro-intestinal and genito-urinary)

hormonal balance

lymph and fascia

muscles and bones and

skills like temperature regulation

– take learning to recognize, evaluate and adjust according to conditions.  Blood pH might dictate changes in kidney function or breathing, for instance.  It takes time to learn that complex complexity.  Moreover, those conditions continue to change in a critical way, as a baby grows from immobile infant to gleeful, running-from-parents two-year-old.

Everything is important to the nervous system, especially hormonal levels, some of which govern how that nervous system is interpreted.  Neurotransmitters like dopamine and serotonin, GABA and glutamate, adrenalin, cortisol, epinephrine, oxytocin and more heavily influence what we think about the information our senses give us.

Here it’s important to pause and talk about some of the main senses you might not have thought about, in addition to the usual tactile, visual, olfactory, tasting, hearing senses we learned about in elementary school.  This isn’t talking about a sense of humor, or common sense.  These are INTERNAL SENSES:

Interoception – this is an ability to interpret what’s going on in our body.  Need to take a breath?  Use the restroom?  Does your tummy ache, or are there butterflies there?  Muscle aches and pains?  This sort of thing gives yourself a heads-up that something might need to be taken care of before it resumes its “normal” state.  Someone whose interoception is maladjusted may either feel pain as much stronger than it is or cannot feel pain well.  This spells difficulty if you’re having a heart attack, and don’t know it.

Proprioception – described as a sense of where we are in space. I find it helpful to define it as body position.  Close your eyes.  Where are you?  Are you lying, sitting, standing, or something in between?  What’s your left foot doing?  This is proprioception and includes things like being able to tell where YOU stop and where the person next to you stands.  People whose proprioception is off may be clumsy, bumping into things as a subconscious way of determining where they are.

Just as a teenager is clumsy as s/he adapts to new information from a fast-growing adolescent body, an embryo (fetus, after 8 weeks gestation) is very busy learning his/her explosively growing body.  I’ve never consulted such a young one, nor do I recall that stage, but does it feel odd to find that you have sensations coming in where you hadn’t before?  Does that feel neutral, welcome, foreign, or alarming?

Neuroception – a term coined by Dr. Stephen Porges, this refers to our sense of safety vs danger.  Think back to when you felt totally safe and comfortable, then contrast it to when you’ve been convinced you’re in danger.  Top of a cliff?  Dark street in an unfamiliar section of town?  Going fast on an icy highway?  Someone whose neuroception isn’t working well may think they’re always in danger – i.e., anxious or shy or suspicious – or that they’re NEVER in danger, which means they lack the common sense to perhaps look both ways before crossing the street.

Neuroception is one of the first somatic (body) concepts a baby learns.  Its first experience is that incoming sensory information, especially that it didn’t expect, means that it’s in grave danger. If the umbilical cord, something floating around in the amniotic fluid, or side of the uterus, touches it, baby is frightened into one of two states. Baby reflexively goes into a freeze state – think of a deer in the headlights, or someone who’s pushed the Jeopardy answer button to a question they don’t have the answer to.  A stronger, more primitive option yet is to shut down, like an opossum playing dead.  Both involve absolutely minimal bodily functions, giving all the resources it has to Mom who must keep them both alive.

An in-utero baby starts learning this at 5 weeks gestation; sometime in the next 7 weeks, it has practiced this enough so that it learns not to shut down or freeze, even with incoming sensory information, especially tactile, from the environment.  At that point, a different danger/safety reflex is initiated in the experience of sensory input.  Baby now has muscles and some body parts to move, so when Baby is startled, by change in position or other sensory input, s/he reflexively throws its head back, arms and legs out.  There’s a slight pause when it shakes a bit, then everything comes into its core, and (eventually) baby cries.

This reflexive reaction to danger will eventually be learned within a few months of birth.  If one of a myriad of things happens – among them being, Baby doesn’t get enough practice, or s/he gets too much electromagnetic field exposure – one or both of these reflexes don’t get learned and set aside.  The baby becomes a child, then an adult, still reacting as though s/he is an immobile and vulnerable infant.  This leads to an enormous amount of problems, which the next newsletter and blog will start to address.