Holger Dannenberg, Hallie Lazaro, Pranav Nambiar, Alec Hoyland, Michael E Hasselmo. Effects of visual inputs on neural dynamics for coding of location and running speed in medial entorhinal cortex. bioRxiv 2020.04.06.027466; doi: https://doi.org/10.1101/2020.04.06.027466

Abstract
“Neuronal representations of spatial location and movement speed are important for a broad range of cognitive functions, including spatial self-localization and memory-guided navigation. Two possible speed signals, by theta frequency or by firing rate, have been hypothesized to provide the velocity signal needed for generating the spatially periodic grid cell firing pattern. However, which of these speed signals is utilized by the brain remains unknown. By manipulating visual inputs and analyzing the time-courses of evoked changes, we demonstrate that changes in spatial stability of grid cell firing correlate in time with changes in speed coding by local field potential theta frequency. In contrast, visual inputs do not affect speed coding by firing rate even if baseline firing rates are changed. Moreover, grid cells maintain a spatially periodic firing pattern, though less stable, in complete darkness. These data suggest that mice use an oscillatory speed signal to perform path integration.”

Holger Dannenberg, Hallie Lazaro, Pranav Nambiar, Alec Hoyland, Michael E Hasselmo. Effects of visual inputs on neural dynamics for coding of location and running speed in medial entorhinal cortex. bioRxiv 2020.04.06.027466; doi: https://doi.org/10.1101/2020.04.06.027466