Entorhinal Neurons Exhibit Cue Locking in Rodent VR

1. Front Cell Neurosci. 2019 Jan 17;12:512. doi: 10.3389/fncel.2018.00512.
eCollection 2018.

Entorhinal Neurons Exhibit Cue Locking in Rodent VR.

Casali G(1), Shipley S(1), Dowell C(1), Hayman R(1)(2), Barry C(1).

Author information:
(1)Department of Cell and Developmental Biology, University College London,
London, United Kingdom.
(2)Institute of Neurology, University College London, 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; and (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 characterize spatially modulated neurons in VR experiments.

DOI: 10.3389/fncel.2018.00512
PMCID: PMC6344450
PMID: 30705621

Auteurs Bordeaux Neurocampus