Effect of spaceflight on major sleep parameters under both LD (A-D) and DD (E-H) conditions.

<p>The average total sleep time (A, E), average length of sleep episode (C, G), and average sleep episode number (D, H) were calculated based on the <i>Drosophila</i> sleep definition. Green, orange and grey boxes represent data of space flown, control-1, and control 2 flies, respectively. White and black bars stand for daytime and nighttime, grey bar stands for subjective daytime in DD. Statistical significance was determined by two-tailed Student’s t-test with unequal variance. n.s. means no statistically significant differences. Error bars represent SEM.