Figure 3. Directionality is independent of plate parameters.

(A) Histogram of radial displacements (see Figure 2) for the entire data set (N  =  250 trajectories) acquired with the scanner-array set-up. (B) Relative direction Δθ of the paths of two animals assayed on the same plate in close succession. The direction of a path is defined as the direction of the end-to-end vector for the path. 0° corresponds to two paths that are parallel to each other, 180° to anti-parallel paths. N = 26 pairs. (C, D) End-to-end vectors of paths of animals started from intermediate positions between the center and the edge of a plate. (C): Freshly poured plates. (D): 12-day-old plates.