I came across this excerpt from an undergrad lecture by prof. Nancy Kanwisher about how grid cells and place cells can function for representations of abstract information.
She referenced four papers that I tracked down (links are to the pdfs):
Constantinescu et al Organizing Conceptual Knowledge in Humans with a Grid-like Code
Taveres et al A Map for Social Navigation in the Human Brain
Omer et al Social place-cells in the bat hippocampus
Johnson & Redish Neural Ensembles in CA3 Transiently Encode Paths Forward of the Animal at a Decision Point