gridcellen

Gridcellen are a class of neurons located in the medial entorhinal cortex (MEC) that fire at multiple spatial locations, producing a characteristic grid-like pattern as an animal moves through an environment. They were first described in rats by Hafting and colleagues in 2005, based on intracellular and extracellular recordings, and later observed in mice, bats, and humans using intracranial recordings or functional imaging.

Key properties of grid cells include the regular, roughly hexagonal arrangement of firing fields across the environment. A single grid cell fires at several locations that form a triangular lattice, creating evenly spaced firing fields. Grid spacing is not uniform across all grid cells: it varies along the dorsoventral axis of the MEC, with multiple modules that differ in spacing, while often sharing a common orientation within a module. The grid pattern remains stable during movement and can realign to new environments, though the overall grid phase and orientation can undergo remapping in novel settings.

Grid cells are thought to provide a metric for spatial navigation and self-location by supporting path integration. They integrate velocity information with head-direction inputs to update an animal’s position over time, a process that complements hippocampal place cells. In addition to grid cells, the MEC contains speed cells, border cells, and head-direction cells, all contributing to a robust spatial representation used for navigation and memory.

Two leading theoretical accounts explain grid cell activity: continuous attractor network models and oscillatory interference models. Both aim to describe how networks generate stable, periodic grid patterns and how grid activity can combine with sensory cues to support accurate navigation. Gridcellen are a central component of the brain’s spatial navigation system and have been studied across multiple species, including humans.