Earlier today I posted about starting in the middle.
I have always been fascinated by how the nervous system is like a mobius strip, in that it seems to effortlessly turn everything coming into it into everything that goes out of it, including all the bio into which it is embedded.
In Todd's blogpost (find link in mine) he included a nice picture of a nesting doll to illustrate how complex systems are composed of simpler subsystems.
I have taken his image and have tried to illustrate how the brain and everything it can do in terms of predictive processing, can mobi-"us" everything, including a sense of self, then project that out onto the surface of the skin through its ability to create representational maps.
This image is still pretty crude. It would work way better as an animation, but I don't know how to make one of those, so just try to imagine this thing in action, the way the brain is, always, always more a verb, not a noun. Not a noun until it's dead.
I have tried to include the way a mobius strip turns everything inside out and outside in.
To me, that's what the neuromatrix is like: a mobius strip, constantly in motion, churning through life like a weird looking egg beater, trying to turn everything into Meaning.
So, you can read it bottom up or top down.
Top-down would be the biopsychosocial aspects of a human brain.
Bottom-up would be bio aspects, constantly and continuously feeding into the mobius strip. Until it's dead.
The middle is where that mobius strip crosses over itself. I think if I had to pick an anatomical location to represent that, it would be brainstem. Fastest way to get to the brainstem from the bottom up is through low-threshold mechanoreceptors and their attached giant big heavily-myelinated very fast fibres. They will work best, though, when top-down has been prepared properly, first.