Figure 1

Effects of 100, 30 and 20 lx white light and red light pulses on NREM sleep and REM sleep during the dark phase. (a, b) The normalized electroluminescence spectra (a.u., arbitrary unit) of white (a) and red (b) LED sources. (c) Time course changes in NREM sleep and REM sleep in mice, which are exposed to 100 lx white light in the day and a 1 h/1 h L (100 lx white or red light)/D cycle or constant darkness at night. Each cycle represents the hourly mean±SEM of NREM sleep and REM sleep. Black, white and red circles indicate the profiles of continuous darkness, white light and red light treatments, respectively. The filled and open bars on the x axes indicate light-off and light-on treatments, respectively, at night. *P<0.05, **P<0.01 indicate significant differences between white light and continuous darkness. ^#P<0.05, ^##P<0.01 indicate significant differences between red light and continuous darkness. Data were assessed via two-way ANOVA followed by a Bonferroni test. (d) Total time spent in NREM sleep and REM sleep of the groups exposed to 100, 30 and 20 lx white or red light, as well as continuous darkness, during 5-h light-on phase. Black, white and red bars show the profiles of continuous darkness, white or red light treatments, respectively. Values are means±SEM (continuous darkness n=7; 100 lx, n=9; 30 lx, n=5-7; 20 lx, n=5, 6). *P<0.05, **P<0.01 compared with continuous darkness, assessed via one-way ANOVA followed by a Bonferroni test.