Deep Credit Without Backprop: The Retrograde Relay

TL;DR: Making reward local prevents interference, but it also breaks deep credit assignment: reward can&rsquo;t reach early layers before eligibility traces evaporate. The fix doesn&rsquo;t need backprop or a coordinator. It needs a relay. When a synapse consolidates, it emits a short-range retrograde &ldquo;credit happened downstream&rdquo; signal. Chain those signals and credit can walk backward…