Fig. 4: Attraction of internal representation to the baseline reference frame is time dependent.
From: Population dynamics of head-direction neurons during drift and reorientation
a, Experimental protocol (top row). Bottom row, average across-session offset (relative to baseline) during the 20 s cue-shift experiment. n = 18 sessions. Darkness periods are highlighted in grey. b, Individual offset traces after resets (light blue; n = 58 events) across darkness periods D2 to D6. The black line shows the mean offset. Offset traces after a −90° reset were reflected across the 0° axis. c, Mean offset during darkness in the 20 s cue-exposure experiment (n = 58 events; dark blue) and in D2 of the 2 min cue-exposure experiment (n = 34 events; grey) (left). Right, mean drift speed over the first 30 s shows a strong reversion to the baseline after a 20 s cue exposure (two-sided Wilcoxon rank-sum test, P = 1.4264 × 10−5, Z = 4.34). Data are mean ± s.e.m. with individual datapoints. d, Drift vector field (left). The arrows indicate the direction of mean drift speed and mean drift acceleration (from n = 58 events). The arrow length was scaled down for illustration. Right, simulated streamlines. The stable regime is highlighted in red. e, Network gain heat maps. Left, 20 s cue-exposure experiment. Data represent instances of reversion to the baseline (n = 43 events). Right, D2 of the 2 min cue-exposure experiment (n = 34 events). f, The gain difference between heat maps in e showing the appearance of new bumps at the locations of cue-shifts (±90°) (left). Right, P-value matrix for the data on the left (two-sided Wilcoxon rank-sum test; pixels where P > 0.001 and/or gain (20 s) < gain (D2) are marked as not a number (NaN)). Time-dependent signals in a and c are shown as mean (solid line) ± s.e.m. (shaded area).
