Angular measurements can be used to quantify collective migration behavior.

<p><b>A</b>) Cellular tracks of confluent monolayers of HaCaT (top) and MDA-MB-231 cells (bottom) in the presence and absence of EGF stimulation. Calibration bar represents 150 µm. <b>B</b>) Confluent monolayers of HaCaT cells in the presence and absence of EGF stimulation were quantified for their collective migration behavior by calculating the average standard deviation of the angle of trajectory (also called the paired random migration index (PRMI Θ_Tajectory) amongst nearest neighboring cells. Random pairing was used to determine whether the observed behavior was local or global amongst the population. <b>C</b>) The same quantification was conducted for MDA-MB-231 cells. <b>D</b>) Cellular tracks of epithelial sheets of HaCaT cells in the presence and absence of EGF stimulation. Calibration bar represents 150 µm. <b>E</b>) Inspection of the spatial distribution of collective migration behavior reveals that EGF stimulation elicits collective migration that propagates away from the leading edge. Double asterisks indicate a <i>p</i> value<0.01.