Autoassociative memory and heteroassociative memory in a three-layered model for Hippocampal formation

摘要

In order to investigate the autoassociative memory and the heteroassociative memory, we propose a three-layered neural network model which consists of a layer of dentate gyrus granule cells, a layer of dentate gyrus mossy cells and a layer of CA3 pyramidal cells. It has been considered that recurrent collaterals in CA3 are related to the autoassociative memory since their structure and synaptic plasticity. However, Lisman considered that those are related to the heteroassociative memory by investigating characteristic time intervals of their synaptic plasticity. Hence Lisman has proposed that the autoassociative memory is realized by bidirectional connections between granule cells and mossy cells in the dentate gyrus and the heteroassociative memory by CA3. We construct a three-layered neural network model according to Lisman's proposal and has succeeded in the autoassociative memory recall and the heteroassociative memory recall. From our results, we consider that the autoassociative memory is realized by a closed loop in the dentate gyrus and CA3.