Podcast with Edvard Moser on grid cells and entorhinal cortex

How does the brain build an internal map of space , and what happens when that map is slightly wrong? Nobel laureate Edvard Moser describes the discovery of grid cells, their modular organization, and the surprising geometric distortions that reveal how the brain calibrates its spatial metric against the physical world. Subscribe for more from the Convergent Science Network podcast series. Edvard Moser joins Paul Verschure and Tony Prescott at the BCBT summer school to discuss his research on the neural basis of spatial navigation. The conversation traces the path from hippocampal place cells to the discovery of grid cells in the medial entorhinal cortex , neurons that fire in strikingly regular hexagonal patterns as an animal moves through space. Moser explains how targeting electrodes to a more dorsal region of entorhinal cortex, guided by neuroanatomist Menno Witter's expertise on hippocampal connectivity, revealed spatial signals that previous studies had missed simply because they recorded in regions where grid spacing was too large for standard-sized environments. The discussion explores the key properties of grid cells and their organization into discrete modules , clusters of cells with rigidly preserved firing relationships across different environments. Within each module, cells maintain consistent phase offsets, orientations, and spatial scales, providing a reusable metric framework that does not need to be rebuilt for every new environment. Moser describes how grid cells depend on speed and direction inputs for path integration but require continuous calibration against external sensory cues, particularly visual landmarks, to prevent cumulative drift errors. Border cells, head direction cells, and speed cells form a local circuit ecosystem that supports and anchors the grid representation. Key topics include how grid cells were discovered and why earlier studies missed them, what modular organization means for generating unique position codes from redundant grid patterns, how border cells anchor and distort grid patterns near environmental boundaries, why grid axes are offset by 7.5 degrees from wall orientations due to a shearing process, how hippocampal place cells create distinct orthogonal maps for different environments from the rigid grid cell input, and what the lateral entorhinal cortex contributes beyond spatial information to hippocampal representations. Part of the Convergent Science Network podcast series from the BCBT Summer School.