Describing Directional Cell Migration with a Characteristic Directionality Time

摘要: Many cell types can bias their direction of locomotion by coupling to external cues. Characteristics such as how fast a migrates and the directedness its migration path be quantified provide metrics that determine which biochemical biomechanical factors affect directional migration, much. To useful, these must reproducible from one experimental setting another. However, most are not because numerical values depend on technical parameters like sampling interval measurement error. address need for metric, we analytically derive metric called directionality time, minimum observation time required identify motion directionally biased. We show corresponding fit function is applicable variety ergodic, biased motions. A ergodic when underlying dynamical properties speed or do change over time. Measuring nonergodic less straightforward but also this class analyzed. Simulations used robustness measurements decoupling errors. As practical example, demonstrate step-by-step, noisy, trajectories chemotactic neutrophils. Because inherent generality, ought useful characterizing broad range motions including intracellular transport, motility, animal migration.