I wonder btw, whether it would be reasonable to assume that serotonin is responsible for error-detection, and dopamine for the actual proces of predictive coding istelf? It's probably not that simple, but i mean, would it be reasonable to assume that these neurotransmitters are playing a major role in those processes?

From a laymans perspective it would seem Obvious. But when it comes to the brain and neurochemistry, things hardly ever realy áre Obvious. Wich is Obvious, ofcourse, because obviously we would all have to be so obviously dumb then, that nothing realy could be Obvious to us. Obviously.