p360fig10.08 The bottom-up on-center off-surround from LGN-to-6-to-4 has a modulatory on-center because of its role in realizing the ART Matching Rule and, with it, the ability of the cortex to dynamically stabilize its learned memories.<BR>||  Modulation of priming by 6-to-4 on-center (Stratford etal 1996; Callaway 1998). On-center 6-to-4 excitation is inhibited down to being modulatory (priming, subthreshold). On-center 6-to-4 excitation cannot activate layer 4 on its own.  Clarifies need for direct path.  Prediction: plays key role in stable grouping, development and learning.  ART Matching Rule!