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. 2014 Oct 30;10(10):e1003927. doi: 10.1371/journal.pcbi.1003927

Figure 2. Successful idiothetic localization in familiar arenas.

Figure 2

(A) Uncertainty (blue particle cloud) either oriented or disoriented initially, showing the estimated pose (cyan arrow) was close to the true pose (red arrow) after 90 seconds. For clarity, only the position of each particle's pose is shown. See also Video S1. (B) Inline graphic at 48 minutes, Inline graphic, was above chance (0.5) either oriented or disoriented initially (Mann-Whitney U-test, p = 4.3×10−164 and p = 7.5×10−161, respectively). In both cases, θ was non-randomly distributed (Rayleigh test, p<10−256) and centred on the true direction (circular m test, p = 0.80 and p = 0.84, respectively) following 48 minutes. Inline graphic (solid lines) and V(θ) (dotted lines) both showed incomplete convergence at 48 minutes (Inline graphic, Wilcoxon test, p = 2.6×10−5; κ-test, p<10−16). Ip kinetics also differed (disoriented, t90 = 2:18; oriented, t90 = 4:32). (C) Simulated grid cell spikes during idiothetic localization in 4 arenas with 1-fold rotational symmetry, initially disoriented (rows 2–5), and initially oriented (row 1). Autocorrelograms of the normalized firing fields from 46–48 minutes are included (right column). See also Table S1. (D) Median Ip and V(θ) functions (left), and Ip(48) distributions (right) are shown for the four arenas in (C) when initially disoriented.