Synaptic conditions for auto-associative memory storage and pattern completion in Jensen et al.'s model of hippocampal area CA3.
Jensen et al. (Learn Memory 3(2-3):243-256, 1996b) proposed an auto-associative memory model using an integrated short-term memory (STM) and long-term memory (LTM) spiking neural network. Their model requires that distinct pyramidal cells encoding different STM patterns are fired in different high-frequency gamma subcycles within each low-frequency theta oscillation. Auto-associative LTM is formed by modifying the recurrent synaptic efficacy between pyramidal cells. In order to store auto-associative LTM correctly, the recurrent synaptic efficacy must be bounded. The synaptic efficacy must be upper bounded to prevent re-firing of pyramidal cells in subsequent gamma subcycles. If cells encoding one memory item were to re-fire synchronously with other cells encoding another item in subsequent gamma subcycle, LTM stored via modifiable recurrent synapses would be corrupted. The synaptic efficacy must also be lower bounded so that memory pattern completion can be performed correctly. This paper uses the original model by Jensen et al. as the basis to illustrate the following points. Firstly, the importance of coordinated long-term memory (LTM) synaptic modification. Secondly, the use of a generic mathematical formulation (spiking response model) that can theoretically extend the results to other spiking network utilizing threshold-fire spiking neuron model. Thirdly, the interaction of long-term and short-term memory networks that possibly explains the asymmetric distribution of spike density in theta cycle through the merger of STM patterns with interaction of LTM network.
Institute for Infocomm Research, Agency for Science Technology and Research (A*STAR), Singapore, Singapore.
Eng Yeow
EY
Cheu
Jiali
J
Yu
Chin Hiong
CH
Tan
Huajin
H
Tang
D000200:Action Potentials / Q000502:physiology; D001245:Association Learning / Q000502:physiology; D056654:CA3 Region, Hippocampal / Q000166:cytology / Q000502:physiology*; D003198:Computer Simulation; D006801:Humans; D007395:Interneurons / Q000502:physiology; D008568:Memory / Q000502:physiology*; D057567:Memory, Long-Term / Q000502:physiology; D008570:Memory, Short-Term / Q000502:physiology; D008959:Models, Neurological; D016571:Neural Networks, Computer; D046709:Pattern Recognition, Physiological / Q000502:physiology*; D017966:Pyramidal Cells / Q000502:physiology; D018091:Receptors, AMPA / Q000502:physiology; D016194:Receptors, N-Methyl-D-Aspartate / Q000502:physiology; D013569:Synapses / Q000502:physiology*; D009435:Synaptic Transmission / Q000502:physiology
D018091:Receptors, AMPA; D016194:Receptors, N-Methyl-D-Aspartate