vector feedback where each neuron gets an individual instruction of how to update and they achieve this not by back propagation because still the original formulation of back prop as we use it in neural networks is not biologically plausible but they achieve this with this backdrop like learning with the feedback network and we'll see how this does but in in essence this feedback network is constructed such that it can give each neuron in the forward pass here detailed instructions on how to update itself right so yeah they have a