Fig 5. Periodicity in conjunctive cell preferred directions.

a) Histograms of the resulting distributions of conjunctive cell angular separations when transformed via the modulo operation at each of the indicated periods (12 bins, radius of 13 angles). b) Kuiper’s V of the transformed distributions of conjunctive cell angular separations at each tested period. Dotted line indicates 0.05 significance criterion based on a nonparametric shuffling procedure which accounted for multiple comparisons. Note that only a transformation by a period of 36° yields a significantly nonuniform distribution. c) Analysis of pure grid cell angular separations. d) Analysis of pure head direction cell angular separations.