Non-Hebbian properties of long-term potentiation enable high-capacity encoding of temporal sequences.
A hypothesis commonly found in biological and computational studies of synaptic plasticity embodies a version of the 1949 postulate of Hebb that coactivity of pre- and postsynaptic elements results in increased efficacy of their synaptic contacts. This general proposal presaged the identification of the first and still only known long-lasting synaptic plasticity mechanism, long-term potentiation (LTP). Yet the detailed physiology of LTP induction and expression differs in many specifics from Hebb's rule. Incorporation of these physiological LTP constraints into a simple non-Hebbian network model enabled development of "sequence detectors" that respond preferentially to the sequences on which they were trained. The network was found to have unexpected capacity (e.g., 50 x 10(6) random sequences in a network of 10(5) cells), which scales linearly with network size, thereby addressing the question of memory capacity in brain circuitry of realistic size.
Granger
R
R
Center for the Neurobiology of Learning and Memory, University of California, Irvine 92717.
Whitson
J
J
Larson
J
J
Lynch
G
G
D000465:Algorithms; D000818:Animals; D006624:Hippocampus / Q000502:physiology*; D007858:Learning / Q000502:physiology*; D017774:Long-Term Potentiation / Q000502:physiology*; D008959:Models, Neurological; D011712:Pyramidal Tracts / Q000502:physiology; D011897:Random Allocation; D018091:Receptors, AMPA / Q000502:physiology; D016194:Receptors, N-Methyl-D-Aspartate / Q000502:physiology; D013569:Synapses / Q000502:physiology*; D013826:Theta Rhythm; D013997:Time Factors
D018091:Receptors, AMPA; D016194:Receptors, N-Methyl-D-Aspartate