p510fig13.38 Dissociation of the read-out of previously learned adaptive weights, or LTM traces, and of the read-in of new weight values enables back-propagating dendritic action potentials to teach the new adaptive weight values.<BR>||  Dissociation of LTM read-out and read-in.  Backpropagating dendritic action potentials as teaching signals.  1. LTM Denditic spines (Rall 1960's)-> Teaching signal - retrograde action potential-> opponent competition.  2. Early predictions: Ca++ currents in learning (Grossberg 1968); role of dendritic spines in learning (Grossberg 1975).  Cf experiments of (Hausser, Markram, Poo, Sakmann, Spruston, etc).