title: Resolving coiled shapes reveals new reorientation behaviors in C. elegans.
abstract: We exploit the reduced space of C. elegans postures to develop a novel tracking algorithm which captures both simple shapes and also self-occluding coils, an important, yet unexplored, component of 2D worm behavior. We apply our algorithm to show that visually complex, coiled sequences are a superposition of two simpler patterns: the body wave dynamics and a head-curvature pulse. We demonstrate the precise Ω-turn dynamics of an escape response and uncover a surprising new dichotomy in spontaneous, large-amplitude coils; deep reorientations occur not only through classical Ω-shaped postures but also through larger postural excitations which we label here as δ-turns. We find that omega and delta turns occur independently, suggesting a distinct triggering mechanism, and are the serpentine analog of a random left-right step. Finally, we show that omega and delta turns occur with approximately equal rates and adapt to food-free conditions on a similar timescale, a simple strategy to avoid navigational bias.
authors.affiliation: Department of Physics and Astronomy, VU University Amsterdam, Amsterdam, The Netherlands.
authors.forename: Onno D
authors.identifier: 0000-0001-8849-7100
authors.initials: OD
authors.lastname: Broekmans
authors.affiliation: Donnelly Center, University of Toronto, Toronto, Canada.|Department of Cell and Systems Biology, University of Toronto, Toronto, Canada.
authors.forename: Jarlath B
authors.initials: JB
authors.lastname: Rodgers
authors.affiliation: Donnelly Center, University of Toronto, Toronto, Canada.|Department of Cell and Systems Biology, University of Toronto, Toronto, Canada.|Department of Physics, University of Toronto, Toronto, Canada.
authors.forename: William S
authors.identifier: 0000-0002-0350-7507
authors.initials: WS
authors.lastname: Ryu
authors.affiliation: Department of Physics and Astronomy, VU University Amsterdam, Amsterdam, The Netherlands.|OIST Graduate University, Onna, Okinawa, Japan.
authors.forename: Greg J
authors.identifier: 0000-0003-3135-3514
authors.initials: GJ
authors.lastname: Stephens
mesh_terms: D000465:Algorithms; D000818:Animals; D001522:Behavior, Animal; D017173:Caenorhabditis elegans / Q000502:physiology*; D003198:Computer Simulation; D008124:Locomotion; D008954:Models, Biological
keywords: C. elegans; behavior; computational biology; image analysis; low-dimensionality; neuroscience; systems biology