Original Research ARTICLE
Entorhinal neurons exhibit cue locking in rodent VR
- 1University College London, United Kingdom
- 2Department of Cell and Developmental Biology, University College London, United Kingdom
- 3Institute of Neurology, University College London, United Kingdom
The regular firing pattern exhibited by medial entorhinal (mEC) grid cells of locomoting rodents is hypothesized to provide spatial metric information relevant for navigation. The development of virtual reality (VR) for head-fixed mice confers a number of experimental advantages and has become increasingly popular as a method for investigating spatially-selective cells. Recent experiments using 1D VR linear tracks have shown that some mEC cells have multiple fields in virtual space, analogous to grid cells on real linear tracks. We recorded from the mEC as mice traversed virtual tracks featuring regularly spaced repetitive cues and identified a population of cells with multiple firing fields, resembling the regular firing of grid cells. However, further analyses indicated that many of these were not, in fact, grid cells because: 1) When recorded in the open field they did not display discrete firing fields with six-fold symmetry; 2) In different VR environments their firing fields were found to match the spatial frequency of repetitive environmental cues. In contrast, cells identified as grid cells based on their open field firing patterns did not exhibit cue locking. In light of these results we highlight the importance of controlling the periodicity of the visual cues in VR and the necessity of identifying grid cells from real open field environments in order to correctly characterise spatially modulated neurons in VR experiments
Keywords: Grid Cell, entorhina cortex, path integration, Spatial cognition, Virtual Navigation, virtual reality
Received: 23 Aug 2018;
Accepted: 10 Dec 2018.
Edited by:Jérôme Epsztein, Institut National de la Santé et de la Recherche Médicale (INSERM), France
Reviewed by:Matthew Nolan, University of Edinburgh, United Kingdom
Christoph Schmidt-Hieber, Institut Pasteur, France
Copyright: © 2018 Casali, Shipley, Dowell, Hayman and Barry. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
PhD. Giulio Casali, University College London, London, United Kingdom, email@example.com
Dr. Caswell Barry, Department of Cell and Developmental Biology, University College London, London, United Kingdom, firstname.lastname@example.org