Phase coding by organization of entorhinal cortex–hippocampus loop circuits

Place information is coded by phases of the place cell firings within one theta cycle in the hippocampus (phase coding). In this study, a possible mechanism of the phase coding in the entorhinal cortex–hippocampus system is presented. The present entorhinal cortex layer II model generated a synchronized theta rhythm. A sequence of places was then coded in a theta cycle by entorhinal–hippocampal loop circuits with delay. The connections between place-related stellate cells were sequentially reinforced by sensory signals. After the learning session, the present entorhinal cortex–hippocampus model reproduced the phase precession.