Exponential distribution of locomotion activity in cell cultures

In vitro velocities of several cell types have been measured using computer controlled video microscopy, which allowed the recording of the cells' trajectories over several days. On the basis of our large data sets we show that the locomotion activity displays a universal exponential distribution. Thus, motion resulting from complex cellular processes can be well described by an unexpected, but very simple, distribution function. A simple phenomenological model based on the interaction of various cellular processes and finite ATP production rate is proposed to explain these experimental results.