title: Grid cells require excitatory drive from the hippocampus.
abstract: To determine how hippocampal backprojections influence spatially periodic firing in grid cells, we recorded neural activity in the medial entorhinal cortex (MEC) of rats after temporary inactivation of the hippocampus. We report two major changes in entorhinal grid cells. First, hippocampal inactivation gradually and selectively extinguished the grid pattern. Second, the same grid cells that lost their grid fields acquired substantial tuning to the direction of the rat's head. This transition in firing properties was contingent on a drop in the average firing rate of the grid cells and could be replicated by the removal of an external excitatory drive in an attractor network model in which grid structure emerges by velocity-dependent translation of activity across a network with inhibitory connections. These results point to excitatory drive from the hippocampus, and possibly other regions, as one prerequisite for the formation and translocation of grid patterns in the MEC.
authors: Kavli Institute for Systems Neuroscience and Centre for the Biology of Memory, Norwegian Brain Centre, Norwegian University of Science and Technology, Trondheim, Norway.
authors: Tora
authors: T
authors: Bonnevie
authors: Benjamin
authors: B
authors: Dunn
authors: Marianne
authors: M
authors: Fyhn
authors: Torkel
authors: T
authors: Hafting
authors: Dori
authors: D
authors: Derdikman
authors: John L
authors: JL
authors: Kubie
authors: Yasser
authors: Y
authors: Roudi
authors: Edvard I
authors: EI
authors: Moser
authors: May-Britt
authors: MB
authors: Moser
mesh_terms: D000200:Action Potentials / Q000187:drug effects / Q000502:physiology*; D000818:Animals; D003198:Computer Simulation; D058787:GABA-A Receptor Antagonists / Q000494:pharmacology; D006624:Hippocampus / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D008297:Male; D008959:Models, Neurological; D009118:Muscimol / Q000494:pharmacology; D009415:Nerve Net / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D020318:Rats, Long-Evans
chemical_list: D058787:GABA-A Receptor Antagonists; D009118:Muscimol