https://astralcodexten.substack.com/p/link-unifying-predictive-coding-with

[epistemic status: I know a little about the predictive coding side of this, but almost nothing about backpropagation or the math behind the unification. I am posting this mostly as a link to people who know more.]

This is a link to / ad for a great recent Less Wrong post by lsusr, Predictive Coding Has Been Unified With Backpropagation, itself about a recent paper Predictive Coding Approximates Backprop Along Arbitrary Computation Graphs.

Predictive coding is the most plausible current theory of how the brain works. I've written about it elsewhere, especially here.