Figure 1.

Figure 1 The RIS interneuron promotes head movement quiescence but not locomotor quiescence during lethargus and stress-induced sleep. (A-D) Locomotor rate assessed by body bends per minute among animals during the L4-to-adult lethargus (A), during the young adult stage (B), and during stress-induced sleep at the young adult stage following exposure to ultraviolet light (C) or Cry5B pore-forming toxin (D). Animals were examined on thin even lawns of E. coli OP50 and examined for the number of sinusoidal body bends (peak-to-peak movement of any body part) in one minute. To select mid-lethargus animals, late-L4 larvae were identified based on vulval morphology, screened one hour later for cessation of pharyngeal pumping as an indicator of lethargus entry, and scored 30 min later for bend rates. For UV-SIS, worm plates were placed lid-down on a 302nm 60mW UV light box for 50 sec and examined 60 min later. For Cry5B-SIS, animals were exposed to Cry5B-expressing bacteria for 5 min, transferred to a thin even lawn of OP50, and examined 10-15 min later. For all bend rate analyses, plates were gently moved to the stereomicroscope field of view and allowed to sit for 1 min prior to examination. Each animal was examined for 1 min and a body bend was defined as a peak-to-peak unit of sinusoidal motion. **P<0.0001 vs. N2, one-way ANOVA with Dunnett’s multiple comparisons test. N=15-20, experimenter blind to genotype. (E-L) Categorization of movement during SIS following UV exposure (E-H) and during exposure to Cry5B (I-L). Each animal was examined for 5 sec and characterized as completely immobile (E and I), head mobile but body immobile (F and J), or head mobile plus body movement of at least 1/10 body-length (G and K). Two-way repeated measures (RM) ANOVA with time as the repeated factor and Sidak’s multiple comparisons test reveals that more ceh-17(lf) than aptf-1(lf) animals are completely immobile under certain SIS conditions (Panel I, ceh-17 vs. each aptf-1 mutant, P<0.05 at 40 min). However, aptf-1 mutants are impaired for head movement quiescence (N2 vs. aptf-1 mutants P<0.05 at multiple time points during UV-SIS and Cry5B-SIS), and not significantly impaired for body movement with the exception of the 30 min time point of UV-SIS, for which aptf-1(tm3287) is different from wild type N2 (P<0.05). H and L show stacked categories of behavior for the time points indicated by shaded boxes within the time courses. Three trials of 25 animals were performed and the experimenter was blind to genotype.