PIV analysis of wt Ecad and cis-Ecad cell migration. (A) Instantaneous velocities were extracted 250–300-µm deep from the migration front for each image and spatially averaged along the migrating axis in kymographs, giving heat maps of the order parameter (−1 means backward and +1 means forward movements). Mean instantaneous velocities (B), order parameters in the velocity field as a function of distance to the front (C), and mean correlation length (D) were extracted from the kymographs (± SEM). ****, P ≤ 0.0001, Student’s t test. wt Ecad cells displayed lower migration speed, migrate forward in a more directed fashion at the monolayer expansion front, and show better correlation in their movements.