Fig. 4: Brief optogenetic activation of dmM CRH neurons elicits P-waves.

a Experimental approach for optogenetically triggering and recording P-waves. b Example recording with spontaneous and a laser-triggered P-wave during REM sleep, including EEG trace, laser stimulation trial, and LFP trace. c–e Average waveform and EEG correlates of spontaneous P-waves (c), laser-triggered P-waves (d), and failed laser pulses (e) during REM sleep (n = 6 mice). Top, averaged LFP signal (shading, ±SD); middle, averaged EEG spectrogram; bottom, averaged power in the high theta frequency band (8–15 Hz). Time point 0 s corresponds to the negative peak of P-waves (c, d) or onset of failed laser pulses (e). f Left, normalized power spectral density during the 1 s interval surrounding spontaneous P-waves, laser-triggered P-waves, failed laser pulses, and randomly selected control time points during REM sleep (n = 6 mice). Right, mean normalized power within the 8–20 Hz range. One-way repeated measures ANOVA (P = 1.06e−5) with Bonferroni post-hoc (control vs spontaneous P-waves, P = 0.002; control vs laser-triggered P-waves, P = 0.025; failed laser vs spontaneous P-waves, P = 0.021; failed laser vs laser-triggered P-waves, P = 0.017). For boxplots, center lines represent the median, box limits represent the interquartile range, and whiskers represent the remaining distribution. g Left, percentage of laser pulses successfully triggering a P-wave for each brain state (n = 6 mice). One-way repeated measures ANOVA (P = 8.95e−7) with Bonferroni post-hoc (REM vs NREM, P = 0.036; REM vs IS, P = 0.005; Wake vs NREM, P = 0.005; Wake vs IS, P = 0.004). Right, success rate of true vs time-shuffled laser pulses during REM sleep. Paired t-test (P = 1.36e−4). h Latencies of laser-triggered P-waves for true and time-shuffled laser pulses (n = 6 mice). i Phase preferences of spontaneous and laser-triggered P-waves relative to EEG theta oscillations (n = 6 mice). Both phase distributions were non-uniform (Rayleigh test, spontaneous P-waves, P = 1.83e−13; laser-triggered P-waves, P = 9.06e−9). For analysis of spectrograms (c–e) and PSDs (f), each frequency component was normalized by its mean power across the 6 s interval surrounding the P-wave or failed laser onset. Error bars and shadings indicate ±SEM unless otherwise stated. Lines, individual mice. *P < 0.05; **P < 0.01; ***P < 0.001. Statistical details (f, g) shown in Supplementary Table 1. Source data are provided as a Source Data file.