Global remapping in granule cells and mossy cells of the mouse dentate gyrus

Hippocampal place cells exhibit spatially modulated firing, or place fields, which can remap to encode changes in the environment or other variables. Unique among hippocampal subregions, the dentate gyrus (DG) has two excitatory populations of place cells, granule cells and mossy cells, which are among the least and most active spatially modulated cells in the hippocampus, respectively. Previous studies of remapping in the DG have drawn different conclusions about whether granule cells exhibit global remapping and contribute to the encoding of context specificity. By recording granule cells and mossy cells as mice foraged in different environments, we found that by most measures, both granule cells and mossy cells remapped robustly but through different mechanisms that are consistent with firing properties of each cell type. Our results resolve the ambiguity surrounding remapping in the DG and suggest that most spatially modulated granule cells contribute to orthogonal representations of distinct spatial contexts.

Automated summary

Hippocampal place cells in the dentate gyrus (DG) exhibit spatially modulated firing, and previous studies have drawn different conclusions about their remapping and role in encoding context specificity. By recording granule cells and mossy cells, two populations of place cells in the DG, as mice foraged in different environments, we found that both cell types remapped robustly but through different mechanisms, contributing to orthogonal representations of distinct spatial contexts.