title: Visual landmarks sharpen grid cell metric and confer context specificity to neurons of the medial entorhinal cortex.
abstract: 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.
authors.affiliation: Department of Clinical Neurobiology, Medical Faculty of Heidelberg University, Heidelberg, Germany.|German Cancer Research Center, Heidelberg, Germany.
authors.forename: José Antonio
authors.initials: JA
authors.lastname: Pérez-Escobar
authors.affiliation: Department of Clinical Neurobiology, Medical Faculty of Heidelberg University, Heidelberg, Germany.|German Cancer Research Center, Heidelberg, Germany.
authors.forename: Olga
authors.initials: O
authors.lastname: Kornienko
authors.affiliation: Department of Clinical Neurobiology, Medical Faculty of Heidelberg University, Heidelberg, Germany.|German Cancer Research Center, Heidelberg, Germany.
authors.forename: Patrick
authors.initials: P
authors.lastname: Latuske
authors.affiliation: Department of Clinical Neurobiology, Medical Faculty of Heidelberg University, Heidelberg, Germany.|German Cancer Research Center, Heidelberg, Germany.
authors.forename: Laura
authors.initials: L
authors.lastname: Kohler
authors.affiliation: Department of Clinical Neurobiology, Medical Faculty of Heidelberg University, Heidelberg, Germany.|German Cancer Research Center, Heidelberg, Germany.
authors.forename: Kevin
authors.identifier: 0000-0001-5319-3721
authors.initials: K
authors.lastname: Allen
mesh_terms: D000200:Action Potentials; D000818:Animals; D004569:Electroencephalography; D018728:Entorhinal Cortex / Q000502:physiology*; D000071038:Grid Cells / Q000502:physiology*; D008810:Mice, Inbred C57BL; D000072458:Orientation, Spatial; D065855:Spatial Processing
keywords: border cells; grid cell; medial entorhinal cortex; mouse; navigation; neuroscience; path integration; speed cells