compute the difference to the desired hidden state and thereby compute an error signal and now we have achieved what we wanted we want an algorithm that doesn't do back prop that only uses local information in order to compute the error signal that it needs to adjust and by local I mean information in the same layer and also the data type that is propagated by F is activations right of hidden representations and by G is also activations of hidden representations both of them are always positive can be encoded by spiking