Fig. 1.

The dynamic index (DI) as a measurement of the cell's dynamic behaviour in 3D. The DI measures the proportion of cell area that has been remodelled between two time points. Shown is a merge of binary images corresponding to the cell area at time t (red) and t_+ 15 min (green). Purely green areas represent newly formed protrusions, whilst purely red areas reflect processes that have been retracted between the first and the second time point. The corresponding DI per time frame is defined as: (areas of new protrusions + areas of retractions) / cell area (see Materials and methods for details).