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Alternating dominance of NMDA and AMPA for learning and recall: a computer model

Chover, Joshua; Haberly, Lewis B.1; Lytton, William W.2, CA

Computational Neuroscience

Physiological studies reveal a dichotomy in biological Hebbian learning: NMDA receptors are utilized for induction of long term potentiation (LTP) whereas AMPA is used for LTP expression. We propose that this dichotomy would have functional value: preventing previously stored memories from interfering with the storage of new memories. A previous hypothesis reduces this interference by temporarily reducing associative weights during learning. Complementary to this model, we propose a dual transmission algorithm in which one set of synaptic weights are used primarily for learning and another primarily for recall. This algorithm shows good performance in a simple neural network model. Biologically, the model could be mediated by a cholinergic switch from dominance of learning-insensitive NMDA receptors to dominance of learning-modifiable AMPA receptors.

Departments of Mathematics and 1Anatomy, University of Wisconsin; 2Departments of Physiology/Pharmacology and Neurology, SUNY, Downstate 450 Clarkson Ave., Box 31 Brooklyn, NY 11203, USA

CACorresponding Author

Received 19 April 2001; accepted 1 June 2001

© 2001 Lippincott Williams & Wilkins, Inc.