A network approach to discerning the identities of C. elegans in a free moving population

The study of C. elegans has led to ground-breaking discoveries in gene-function, neuronal circuits, and physiological responses. Subtle behavioral phenotypes, however, are often difficult to measure reproducibly. We have developed an experimental and computational infrastructure to simultaneously record and analyze the physical characteristics, movement, and social behaviors of dozens of interacting free-moving nematodes. Our algorithm implements a directed acyclic network that reconstructs the complex behavioral trajectories generated by individual C. elegans in a free moving population by chaining hundreds to thousands of short tracks into long contiguous trails. This technique allows for the high-throughput quantification of behavioral characteristics that require long-term observation of individual animals. The graphical interface we developed will enable researchers to uncover, in a reproducible manner, subtle time-dependent behavioral phenotypes that will allow dissection of the molecular mechanisms that give rise to organism-level behavior.Mechanisms of Aging and Dementia Training grant (NIH grant: T32 AG20506) and the Ruth L. Kirschstein National Research Service Award (NIH Grant: 1F31AG045017) to P.B.W., from the National Institutes of Health (NIGMS, NIA, NIMH), the Ellison Medical Foundation, and the Daniel F. and Ada L. Rice Foundation to R.I.M., and from the grants for Department of Defense’s Army Research Office (No. W911NF-14-1-0259) and the John Templeton Foundation (No. FP053369-A//39147) to L.A.N.A. A.T.-C. was supported by the Fundação para a Ciência e Tecnologia (FCT) individual fellowship SFRH/BPD/79469/2011. The authors thank the members of the L.A.N.A and R.I.M. Laboratories for their support and critical reading of the manuscript. Thanks to K. Day for scoring validation recordings and D.J. Bridge for insightful discussion. Some strains were provided by the CGC, which is funded by NIH Office of Research Infrastructure Programs (P40 OD010440