Distributions of small-scale parameters support generalized SPP.

(A) Distribution of mouse fibroblast instantaneous speeds calculated from cell nuclei center-of-mass displacement between image capture events (blue). The red line is a fit to the form , which is the distribution of speeds expected for a Gaussian distribution of velocities. (B) Distribution of turning angles of mouse fibroblast trajectories (blue), SPP models with constant Dr (green), Gaussian distributed Dr (red), and a run-and-tumble model with Gaussian distributed Dr during runs and exponentially distributed tumbling events. The distribution of rotational diffusion constants is the same in both heterogeneous cases to highlight the effect of incorporating tumbling events into the system. (C) Run-time distribution for mouse fibroblast cells (blue) is well fit by an exponential distribution (red).