Review for NeurIPS paper: Can the Brain Do Backpropagation? --- Exact Implementation of Backpropagation in Predictive Coding Networks

Weaknesses: I have some critical remarks: 1.) Weight transport problem. This problem is not solved in the model. In fact the model needs symmetric weights. Feedback alignment will probably not work here, as I assume that the existence of an equilibrium state necessitates symmetric weights. The authors claim that the update rules are local.