“…Grid cells, typically recorded from freely navigating rats and humans (Hafting, Fyhn, Molden, Moser, & Moser, ; Sargolini et al, ; Jacobs et al, ), display a regularly spaced pattern of neural firing (“grids”) that span the environment. In addition to their presence during spatial navigation, studies have also observed such grid coding during tasks involving representation of conceptual categories, imagination, and scene processing (Bao et al, ; Bellmund, Deuker, Schroder, & Doeller, ; Constantinescu, O'reilly, & Behrens, ; Garvert, Dolan, & Behrens, ; Horner, Bisby, Zotow, Bush, & Burgess, ; Killian, Jutras, & Buffalo, ). One theoretical interpretation of such grid coding is that it forms the basis of a universal spatial metric representation that underlies many, if not all, forms of spatial and nonspatial representations (Behrens et al, ; Bellmund, Gardenfors, Moser, & Doeller, ; Bush, Barry, Manson, & Burgess, ; Hasselmo, Giocomo, Brandon, & Yoshida, ; Hawkins, Lewis, Klukas, Purdy, & Ahmad, ).…”