Grid cells form a global representation of connected environments.
The firing patterns of grid cells in medial entorhinal cortex (mEC) and associated brain areas form triangular arrays that tessellate the environment [1, 2] and maintain constant spatial offsets to each other between environments [3, 4]. These cells are thought to provide an efficient metric for navigation in large-scale space [5-8]. However, an accurate and universal metric requires grid cell firing patterns to uniformly cover the space to be navigated, in contrast to recent demonstrations that environmental features such as boundaries can distort [9-11] and fragment [12] grid patterns. To establish whether grid firing is determined by local environmental cues, or provides a coherent global representation, we recorded mEC grid cells in rats foraging in an environment containing two perceptually identical compartments connected via a corridor. During initial exposures to the multicompartment environment, grid firing patterns were dominated by local environmental cues, replicating between the two compartments. However, with prolonged experience, grid cell firing patterns formed a single, continuous representation that spanned both compartments. Thus, we provide the first evidence that in a complex environment, grid cell firing can form the coherent global pattern necessary for them to act as a metric capable of supporting large-scale spatial navigation.
Institute of Neurology, UCL, Queen Square, London WC1N 3BG, UK; Research Department of Cell and Developmental Biology, UCL, Gower Street, London WC1E 6BT, UK. Electronic address: francis.carpenter.12@ucl.ac.uk.
Francis
F
Carpenter
Research Department of Cell and Developmental Biology, UCL, Gower Street, London WC1E 6BT, UK; Centre for Mathematics and Physics in the Life Sciences and Experimental Biology, UCL, Gower Place, London WC1E 6BT, UK.
Daniel
D
Manson
Institute of Behavioural Neuroscience, UCL, Bedford Way, London WC1H 0AP, UK.
Kate
K
Jeffery
Institute of Neurology, UCL, Queen Square, London WC1N 3BG, UK; Institute of Cognitive Neuroscience, UCL, Queen Square, London WC1N 3AR, UK.
Neil
N
Burgess
Research Department of Cell and Developmental Biology, UCL, Gower Street, London WC1E 6BT, UK. Electronic address: caswell.barry@ucl.ac.uk.
Caswell
C
Barry
D000818:Animals; D018728:Entorhinal Cortex / Q000166:cytology / Q000502:physiology*; D004777:Environment; D008297:Male; D051381:Rats; D013037:Spatial Behavior / Q000502:physiology*