Figure 7. Time-averaged Kuramoto order parameter .

for experiments at different cell densities . At cell densities above 0.3%, is high indicating coherent oscillatory dynamics of the cells in the population. At cell densities below 0.3% the low value of shows that the cells oscillate in a decoherent fashion. The critical cell density lies at 0.3%. The error bars represent the standard deviation and provide a measure for the fluctuations of the phase synchronisation in each individual experiment.