Changes in Postural Syntax Characterize Sensory Modulation and Natural Variation of C. elegans Locomotion
(A) Worm tracks in different conditions: on food (n = 34), off food (n = 23), and off food with an attractant (benzaldehyde) (n = 25). Tracks for different worms start at the red dot and are aligned with their long-axis arranged vertically. Worms on food explore the region of the food but rarely leave, while off food they explore a larger area. In the presence of an attractant, worms explore a large area, but in a more directed way. (B) A plot shows the distribution of R2 values for worms in the different conditions. The fit quality is no worse for worms off food or performing chemotaxis even though the postures are derived only for worms on food. For comparison, the distribution of fits is also shown for an uncoordinated mutant unc-79(e1068) that is poorly fit using the wild type on food postures. Numbers in the legend are mean ± standard deviation of the R2 distributions. (C) Comparisons between the frequencies of four selected trigrams in the three conditions. The rank of each sequence in the repertoire of worms in each condition is shown in red. * indicates p < 4.1 x 10−4, chosen to control the false discovery rate at 5% across multiple comparisons.