title: Temporal analysis of stochastic turning behavior of swimming C. elegans.
abstract: Caenorhabditis 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.
authors.affiliation: Department of Physics and Center for Brain Science, Harvard University, Cambridge, Massachusetts, USA.
authors.forename: Nikhil
authors.initials: N
authors.lastname: Srivastava
authors.forename: Damon A
authors.initials: DA
authors.lastname: Clark
authors.forename: Aravinthan D T
authors.initials: AD
authors.lastname: Samuel
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D017173:Caenorhabditis elegans / Q000235:genetics / Q000502:physiology*; D016014:Linear Models; D008954:Models, Biological; D009043:Motor Activity / Q000235:genetics; D009154:Mutation; D011336:Probability; D013269:Stochastic Processes; D013550:Swimming; D013997:Time Factors