Signal flow in a prefrontal cortical circuit model for working memory loading

Abstract

The active storage process for working memory, which is substantiated by a specific sustained activity of a population of neurons in the prefrontal cortex, is a circuit property of the cortex. To analyze the circuit mechanisms of this process, we constructed a two-layer prefrontal cortical circuit model. The network with asymmetric inter-laminar connections produces transient, cue-period activity in one layer and delay-period activity in the other layer. The peak firing rate in the delay-period is low enough even though the model neurons do not have NMDA-type channels. The simulation shows that the postsynaptic currents have layer-specific spatio-temporal profiles, which are necessary for the coexistence of the different activity patterns.