Fig. 5. During SFICM, cell speed is modulated by the frequency of fast increases in contact area (burst). Individual cell-substrate contact areas were imaged under SFICM at the indicated shear stress values by RICM at 40x magnification. The relative positions of cell rear (closed diamonds) and front (open squares) edges are plotted as a function of time. Arrows indicate the rapid increases in cell-substrate contact area (bursts).