Fig. 2: Characterization of sleep in N. vectensis using behavioral criteria.
From: DNA damage modulates sleep drive in basal cnidarians with divergent chronotypes
a Behavioral recording setup. b Normalized pixel change was used to quantify movement. Red dotted line indicates the movement threshold. Top images and arrows illustrate pixel change below (left) and above (center, right) the threshold. c Rhythmic locomotor activity during 72 h under LD. d Average locomotor activity during rest (ZT18-6) and active (ZT6-18) periods (n = 33; ****p < 0.0001). e Examples of fast (top) and slow (bottom) responses to light stimulation (yellow line). f Response latency versus quiescent bout duration before light stimulation. The dashed vertical line (determined from g) separates two behavioral responses. g Classification error across quiescence durations. The minimum defines the optimal threshold (8 min) separating fast and slow responses. h Average response latency for animals quiescent less vs. more than 8 min before stimulation (n = 72; ****p < 0.0001). i Response latency versus quiescent bout duration before food stimulation. The dashed vertical line (determined from j) separates two behavioral responses. j Classification error across quiescence durations. The minimum defines the optimal threshold (8 min) separating fast and slow responses. k Average response latency for animals quiescent less vs. more than 8 min before food stimulation (n = 53; ****p < 0.0001). l Sleep time during 72 h under LD (n = 33) and DD (n = 24) in WT N. vectensis. m Average sleep time during ZT18-6 vs. ZT6-18 under LD (n = 33; ****p < 0.0001). n LSP analysis of sleep under LD and DD. o Sleep time during 72 h under LD (n = 34) and DD (n = 26) in NvClkΔ/Δ N. vectensis. p Average sleep time during ZT18-6 and ZT6-18 under LD (n = 34; ****p < 0.0001). q LSP analysis of sleep under LD and DD. r Open and closed tentacle posture. s Average sleep time for open or closed posture (n = 33; **p < 0.01). t Sleep time in Ctl (n = 22) and SD (n = 24) animals before and after SD (ZT20-ZT4). u Average sleep time in Ctl and SD animals at ZT10-16 (Ctl: n = 22, SD: n = 24; *p < 0.05). v Sleep time in Ctl (n = 24) and SD (n = 28) animals before and after SD (ZT8-ZT16). w Average sleep time in Ctl and SD animals at ZT22-ZT4 (Ctl: n = 24, SD: n = 28). Boxplots show median (center line), interquartile range (box), and minima/maxima (whiskers); individual data connected in (d, m, p); mean (black cross) in (h, k, s, u, w). Data in (c, l, o, t, v) are presented as mean ± SEM. White, black, and red horizontal lines represent periods of light, dark, and SD, respectively. Wilcoxon signed-rank test (one-tailed) for (d, m, p). Mann-Whitney Wilcoxon (one-tailed) for (h, k, s, u, w). LSP analysis with p < 0.01 if period indicated. p > 0.05 if ns (n, q).
