Fig. 3. Investigation into whether the ECM deformation could be measured directly from DIC images. (A) A segmented DIC image. Above-threshold (red) spots were used as ECM landmarks and tracked over time. (B) Color overlays of bead (red) and DIC (green) tracks (cross indicates initial position in the sequence). Tracks that are close to each other show the same pattern of movement (circle). (C,D) The magnitude and direction of selected bead and DIC tracks taken from five experiments were analyzed. A high correlation was found between both the (C) magnitude and (D) direction of the bead and DIC displacements. Bar, 20 µm.