Navigating through crowded, dynamically changing environments requires the ability to keep track of other individuals. Grid cells in the entorhinal cortex are a central component of self-related navigation but whether they also track others’ movement is unclear. Here, we propose that entorhinal grid-like codes make an essential contribution to socio-spatial navigation. Sixty human participants underwent functional magnetic resonance imaging (fMRI) while observing and re-tracing different paths of a demonstrator that navigated a virtual reality environment. Results revealed that grid-like codes in the entorhinal cortex tracked the other individual navigating through space. The activity of grid-like codes was time-locked to increases in co-activation and entorhinal-cortical connectivity that included the striatum, the hippocampus, parahippocampal and right posterior parietal cortices. Surprisingly, the grid-related effects during observation were stronger the worse participants performed when subsequently re-tracing the demonstrator’s paths. Our findings suggests that network dynamics time-locked to entorhinal grid-cell-related activity might serve to distribute information about the location of others throughout the brain.
Bibliographical noteFunding Information:
The authors would like to thank Paul Anderson for excellent discussions, Ronald Sladky for support with the MRI sequences, and Magdalena Boch for advice on the eye-tracker setup. I.C.W. is supported by the Austrian Science Fund (FWF, P 34775). M.S. is supported by the National Institute of Neurological Disorders and Stroke (NINDS) of the National Institutes of Health (NIH, K99NS126715).
© 2023, The Author(s).