Fig. 3: The trajectories of isolated cells have the characteristics of self-attracting walks.
a Kymograph of an isolated cell on a W = 20 μm track, overlaid with its footprint field φ(x, t) defined as the cumulative time spent on a given position. b Sketch of the φl and φr measurements. Top: the cell sits on the right edge of the footprint, its right edge being outside with φr ≃ 0 while its left edge is within, φl > 10 h. Bottom: the cell is completely within the footprint, with comparable high values of φl and φr. The symbols are reported in panel c to show where each situations sits in the φl − φr space. c Average acceleration of isolated cells on 20 μm tracks as a function of the values of φ at both cell ends. This heatmap was made from 75,088 data points from n = 131 cell trajectories from two independent experiments. d Sketch of the persistent self-attracting walk model. Whether it is on the edge of its footprint (top) or in its interior, the walker have different probabilities to jump in the same direction as before or to turn back, set by two parameters k and β. e Discretised experimental trajectory of an oscillating cell (same cell as panel a) allowing to measure the reversal statistics within and on the edge of the span. f Simulated trajectories of an agent following the PSATW dynamics with the same parameters as infered in (e).
