All there were were fireflies – and from them you could infer the meadow. -Rebecca Elson
In my previous essay, I spent a good deal of time exploring the neuro-anatomy of the Autonomic Nervous System, particularly the ramifications (by which I mean branches, not consequences) of the Vagus nerve. I compare the Vagus to a webbing of cotton candy that ensheaths, and myceliates (that's a made-up word that connotes the manner in which the Vagus, like a mycelial network, grows through us) the visceral organs, and that extends all the way to the toes and the fingertips. I've gone to some length to help you visualize this system, in its magnificence, as a kind of web, rather than as a system of wires, because its only when you begin to understand the degree to which it penetrates organs and tissues with ultrafine filaments that you can properly grasp what interoception is.
We tend to think of our senses as the five that point outward, and about which most of us were taught in school. Vision, hearing, taste, smell, touch. Each of these sense organs has specialized neural receptors that are highly differentiated: from the rods and cones in the retina of the eye, to the hair cells of the ear, to the tastebuds. Each of these senses relies on a profound refinement of neural architecture that is organized into a differentiated sensory apparatus whose function is to transduce some form of information into signals that we can understand.
These specialized sensory hair cells (modified neurons) in the inner ear are responsible for sound detection. On the right is a scanning electron micrograph of the hair bundles.
Interoception is the sixth sense. It is an inward listening sense, and its primary neural architecture is this vast surveillance web of the Vagus: our innernet. Take vision, hearing, and touch as metaphors. Now turn them inward. This is the internal landscape that interoception illuminates, colors, amplifies, and texturizes. Interoception sings the body electric.
70% of vagal fibers are afferent, flowing upward from the body to the brain. And what is the information that they are carrying? Interoceptive inputs from the interior of the body. And how can they be so nuanced? Due to the vagal architecture elucidated in the previous article.
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Most of us live in a modern culture that for a variety of reasons, some mundane, and some deeply insidious, has lost contact with the felt vocabularies of interiority. Yet as assuredly as vision, hearing, smell, taste, and touch convey information about our surroundings that can be interpreted to help us make sense of our world, information from interoceptive awareness can (and must, for us to thrive) be accurately assembled into meaning.
Some people call this awareness bodily intuition, some people call it the felt sense. It is the intersection of internally oriented sensation, emotion, and memory: the living, present moment embodied flavor of what it feels like to be in our bodies in this moment. If contacted, attended to, and approached with discernment it generates a reliable non-cognitive field of information through which we can experience our lives. It is a doorway to knowing ourselves.
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