Keep in mind that artificial neural network are not meant to simulate biological neural networks. They are just inspired by a simplified (and obviously flawed)

Keep in mind that artificial neural network are not meant to simulate biological neural networks. They are just inspired by a simplified (and obviously flawed) computational model of the brain from way back in the stone age of neuroscience. Finding parallels between what ANNs evolved into today and the little we know about the brain may be interesting, but don't think, even for a moment, that you have a model for "backpropagation in the brain". P.S.: I like the implied criticism of the Human Brain Project at 50:10 - "You need a computational theory (not a billion euros) to recognize what you discovered!". We really need to work on theoretical models of computation before we throw money and hardware at simulations. No emergent behavior is going to jump out and save us that step.