TY - JOUR TI - Visual landmarks sharpen grid cell metric and confer context specificity to neurons of the medial entorhinal cortex AU - Pérez-Escobar, José Antonio AU - Kornienko, Olga AU - Latuske, Patrick AU - Kohler, Laura AU - Allen, Kevin A2 - Eichenbaum, Howard VL - 5 PY - 2016 DA - 2016/07/23 SP - e16937 C1 - eLife 2016;5:e16937 DO - 10.7554/eLife.16937 UR - https://doi.org/10.7554/eLife.16937 AB - Neurons of the medial entorhinal cortex (MEC) provide spatial representations critical for navigation. In this network, the periodic firing fields of grid cells act as a metric element for position. The location of the grid firing fields depends on interactions between self-motion information, geometrical properties of the environment and nonmetric contextual cues. Here, we test whether visual information, including nonmetric contextual cues, also regulates the firing rate of MEC neurons. Removal of visual landmarks caused a profound impairment in grid cell periodicity. Moreover, the speed code of MEC neurons changed in darkness and the activity of border cells became less confined to environmental boundaries. Half of the MEC neurons changed their firing rate in darkness. Manipulations of nonmetric visual cues that left the boundaries of a 1D environment in place caused rate changes in grid cells. These findings reveal context specificity in the rate code of MEC neurons. KW - grid cell KW - medial entorhinal cortex KW - navigation KW - path integration KW - speed cells KW - border cells JF - eLife SN - 2050-084X PB - eLife Sciences Publications, Ltd ER -