Population-Level Analysis of Human Grid Cell Activation

The groundbreaking discovery of grid cells in the rodent medial entorhinal cortex has led to unparalleled understanding of the neural underpinnings of spatial navigation. These cells show remarkably regular firing patterns, with neighboring firing fields arranged in 60° intervals, and it has been suggested that they provide the spatial metric underlying different cognitive functions, from path integration to the organization of conceptual knowledge. The physiological properties of grid cells mean that the putative signature of these neurons can be observed at the macroscopic level in the blood oxygenation level-dependent response using functional magnetic resonance imaging and local field potentials from intracranial implant patients. In this chapter, we provide a step-by-step guide as to the methods used to assess the activity from populations of grid cells (i.e., grid-cell-like representations) in humans, from the preprocessing of data to the calculation of grid cell metrics. Furthermore, we outline different variants of this analysis as well as reviewing the extant data relating to grid cell function in humans. Finally, we provide an overview as to the future directions of grid cell research in humans.