From what I get this whole thing is more like an abstract ruleset describing how decision making in the brain works, rather than a brain model. Or am I wrong, is there anyone who built a network model based on this theory?
[1] https://en.wikipedia.org/wiki/Predictive_coding [2] http://www.jmlr.org/papers/volume6/winn05a/winn05a.pdf
"We turn to the equivalent message passing for continuous variables, which transpires to be predictive coding [...]"
It could be that belief propagation is in the context of discrete variables, whereas predictive coding is in the context of continuous, both of which are a form of (variational) message passing.