Srivastava, NikhilClark, Damon A.Samuel, Aravi2013-03-142009Srivastava, Nikhil, Damon A. Clark, and Aravinthan D.T. Samuel. 2009. Temporal analysis of stochastic turning behavior of swimming C. elegans. Journal of Neurophysiology 102(2): 1172–1179.0022-3077http://nrs.harvard.edu/urn-3:HUL.InstRepos:10403684Caenorhabditis elegans exhibits spontaneous motility in isotropic environments, characterized by periods of forward movements punctuated at random by turning movements. Here, we study the statistics of turning movements—deep \(\Omega\)-shaped bends—exhibited by swimming worms. We show that the durations of intervals between successive \(\Omega\)-turns are uncorrelated with one another and are effectively selected from a probability distribution resembling the sum of two exponentials. The worm initially exhibits frequent \(\Omega\)-turns on being placed in liquid, and the mean rate of \(\Omega\)-turns lessens over time. The statistics of \(\Omega\)-turns is consistent with a phenomenological model involving two behavioral states governed by Poisson kinetics: a “slow” state generates \(\Omega\)-turns with a low probability per unit time; a “fast” state generates \(\Omega\)-turns with a high probability per unit time; and the worm randomly transitions between these slow and fast states. Our findings suggest that the statistics of spontaneous \(\Omega\)-turns exhibited by swimming worms may be described using a small number of parameters, consistent with a two-state phenomenological model for the mechanisms that spontaneously generate \(\Omega\)-turns.en-USJournal Article10.1152/jn.90952.2008