Grid cells in entorhinal cortex of freely-moving rats provide a strikingly periodic representation of self-location which is suggestive of very specific computational mechanisms-. However, their existence in humans and distribution throughout the brain are unknown. Here we show that the preferred firing directions of directionally-modulated grid cells in rat entorhinal cortex are aligned with the grids, and that the spatial organization of grid cell firing is more strongly apparent at faster than slower running speeds. Since the grids are also aligned with each other,, we predicted a macroscopic signal visible to functional magnetic resonance imaging (fMRI) in humans. We then looked for this signal as participants explored a virtual reality environment, mimicking the rats’ foraging task: fMRI activation and adaptation showing a speed-modulated 6-fold rotational symmetry in running direction. The signal was found in a network of entorhinal/subicular, posterior and medial parietal, lateral temporal and medial prefrontal areas. The effect was strongest in right entorhinal cortex, and the coherence of the directional signal across entorhinal cortex correlated with spatial memory performance. Our study illustrates the potential power of combining single unit electrophysiology with fMRI in systems neuroscience. Our results provide the first evidence for grid-cell-like representations in humans, and implicate a specific type of neural representation in a network of regions which support spatial cognition and also, intriguingly, autobiographical memory.
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