Fig. 5. Touch-induced cellular contractions propagate like a wave. Touching stimulations of a cell induced a propagation of contraction to the surrounding cells. The contraction seemed to spread with Ca²⁺ wave propagations. To show the contraction clearly, high magnification Nomarski images after stimulation were arranged with time. Arrowheads at 15.8 seconds indicate transient bleb formation in the cell membrane, sometimes accompanied with Ca²⁺ waves. Rows (a) and (b) show images magnified x2 of two areas marked `a' and `b' in the top row (see image labeled 0 seconds). Arrows indicate corresponding regions to show the contractions. Supplementary material Movies 1, 2 facilitate the understanding of the contraction.