Fig. 6: Optogenetic activation of SLD orexin signaling prolongs REM sleep bouts.
a Schematic drawing for optogenetic activation of the SLD orexin terminals. b Representative viral infections of ChR2-mCherry+ (red) in the LH orexin-A+ (blue) neurons (left, scale bar: 50 μm) and optical-fiber location above the SLD (right, scale bars: 500 and 50 μm in magnification). c Representative trials of raw EEG/EMG recordings during 20-Hz optical activation (20 pulses every 3 s) of SLD orexin signaling during NREM sleep. Purple arrows indicated wakefulness. d Heatmap of EEG (left)/EMG (right) recordings from all tested trials in the mouse in (c). EEG/EMG recordings before wakefulness (purple line) were normalized and averaged in the bottom. Blue shadow represented SEM. e, f Effects of optical activation during NREM sleep on the total EEG power (e, 5-Hz: t5 = 2.442, P = 0.0585; 10 Hz: t5 = 3.939, P = 0.0110; 20 Hz: t5 = 4.633, P = 5.667 × 10−3) and EMG amplitude (f, 5 Hz: t5 = 1.610, P = 0.168; 10 Hz: t5 = 2.180, P = 0.0811; 20 Hz: t5 = 5.056, P = 3.912 × 10−3) (n = 6 orexinChR2 mice). OrexinmCherry mice was set as control (n = 5 mice; EEG (20 Hz): t4 = 0.840, P = 0.448; EMG (20 Hz): t4 = 0.506, P = 0.640). All analyzed by two-sided paired t-test. g Effects of optical activation during NREM sleep on the EEG theta/total power ratio (n = 6 orexinChR2 mice, two-sided Wilcoxon signed-rank test; 5 Hz: z = 0.105, P = 0.917; 10 Hz: z = 1.572, P = 0.116; 20 Hz: z = 2.201, P = 0.0277). h Procedures of closed-loop optogenetics during REM sleep. i, j Effects of optical activation (20 Hz, 20 pulses every 3 s) during REM sleep on the EEG theta power (i, t8 = 3.381, P = 9.624 × 10−3), EMGREM/NREM ratio (i, t8 = 2.126, P = 0.0662), and episode duration (j, t8 = 2.368, P = 0.0454) (n = 9 orexinChR2 mice). All analyzed by two-sided paired t-test. Data represent mean ± SEM. *P < 0.05; **P < 0.01. Source data are provided as a Source Data file.
