Cellular and Network MechanisMS of Grid Cell Firing Patterns

Abstract

Grid cells in the entorhinal cortex encode information about spatial representation by firing at hexagonally spaced intervals that tile the local environment. Stellate cells (SCs) are thought to be putative grid cells and our aim is to understand how the intrinsic cellular properties of SCs affect the firing fields of grid cell networks. We aimed to achieve this by recreating a detailed mathematical model of a SC (based on previous experimentally constrained models) and study how key conductances in this model characterize its dynamics and the role of these intrinsic properties at a network level. The distinct features of stellate cells we studied using simulations were the generation of subthreshold oscillations and clustering of action potentials. By building simplistic networks of excitatory SCs and inhibitory interneurons, we were able to show how changes in synaptic input to SCs via variations in inhibitory inputs affected the clustering of SCs. Understanding mechanisms governing the cellular and network level properties can help provide insights into the factors governing grid cell firing fields and spatial representation.