Making Room for the Place-Grid Coupled Dynamics

Under the “spatial modulation continuous attractor network” (SCAN) model, insightful theoretical discussions have been proposed arguing that no direct sensory input signaling velocity to grid cells is required during locomotion, and no place cell activity seems to constitute a summation of grid cells. The model focuses less on explaining the dynamic relationship between place and grid cells as a fundamental component for coding space and time. This commentary highlights, however, that the place-grid coupled dynamics could represent the core mechanism that keeps coherent spatial coded information. This coupling mode between grid- and place-cells seems weak in SCAN, but it is irreducible and crucial for cognitive mapping.