Storage and recall of dynamical patterns in neural network models of hippocampus

We propose a four-layered neural network model and a five-layered neural network model for the hippocampal system by extending the three-layered model given by Araki and Aihara (1998), in order to introduce an effect of auto-recurrent connections in CA3 and also an effect of cholinergic modulation in CA1 and CA3 from the medial septum. We investigate the storage and the recall of dynamical patterns for the proposed models with or without inhibitory connections in CA3. We clarify two different sequential patterns that the storage and the recall succeeded for the proposed models, but not for the original three-layered model. We discuss an effect of acetylcholine to neurons in CA1 and CA3 transmitted from the medial septum.