Figure 3

A power law distribution of active/inactive state residence times in C. elegans episodic swimming. (A) Appearance frequency of number of active pixels in a representative animal for a single image difference frame. Bimodal distribution of active pixels in normalized probability density (NPD) was separated at 10–20 pixels/frame. The active state threshold was ≥ 12 active pixels to obtain residence-time series (details in “Methods”). (B, C) Residence-time series in the active (B) and inactive (C) states with the y-axis in log scale. Activity periods above and below the active state threshold (separated by a red horizontal line on 5-s scale in Fig. 2C) were defined as active and inactive periods, respectively. (D–G) Mean and standard deviations of NPD of residence times in active state (red) and in inactive state (blue) among individual animals in indicated time regime were shown in log–log plot. Fitting was performed over 0.3–5.0 s for active states and over 1–50 s for inactive states. The fit line is shown as a black line. high-motility vs. low-motility periods are as described in “Methods” (wild-type) and the main text (egl-4 mutants).