> Backprop is considered biologically implausible This is not true. See Neural Back propagation [1]. There are known mechanisms for backwards feedback between

> Backprop is considered biologically implausible This is not true. See Neural Back propagation [1]. There are known mechanisms for backwards feedback between neural connections, for example Spike Timing Dependent Plasticity - where neural inputs that are well correlated in time and potential to output firings are strengthened over time. These phenomena are vital to learning and neural development. [1] http://en.m.wikipedia.org/wiki/Neural_backpropagation http://en.m.wikipedia.org/wiki/Neural_backpropagation