Hexagonal firing fields of entorhinal cortex grid cells
40 cm
10°
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Grid Module / Scale:
Grid cells (Moser lab, 2005; Nobel Prize 2014) fire in a hexagonal lattice covering the animal's environment. The pattern is defined by: spacing λ (30–300 cm, increasing from dorsal to ventral mEC), orientation θ (offset ~10–30° from environment walls), and phase (shifts the entire grid). Three basis vectors at 60° angles generate the hexagonal lattice.
Path integration: Multiple grids with different spacings (ratio ≈ √e ≈ 1.65× between modules) create a unique code for every location — like a Chinese remainder theorem for space. The ~10⁷ distinct patterns enable accurate position coding with no external landmarks.