A probabilistic model for the ultradian timing of REM sleep in mice
Fig 1
Correlation between REM sleep duration and inter-REM interval.
(A) Example EEG power spectrogram, EMG amplitude, and hypnogram with definitions of terms. REMpre, duration of the preceding REM sleep episode; inter-REM, duration of subsequent interval till next REM episode; |W|, sum of the durations of all wake episodes during the inter-REM interval; MA, microarousal (wake bouts ≤ 20 s); |N|, sum of the durations of all NREM episodes (including MAs) during the inter-REM interval. (B) Scatter plots with REMpre on the x-axis and subsequent inter-REM duration (left), |N| (middle), and |W| (right) on the y-axis. The results of linear regression fits are shown in red (P<0.00001 for all 3 slopes, n = 5098 sleep cycles from 72 mice recorded during the light phase).