Figure 1.

Mice implanted with EEG electrodes exhibited normal sleep architecture. A, Experimental time line: 14 d after electrode implantation, mice were placed in recording chambers and allowed to habituate for 3 d followed by 3 d of continuous EEG recording. B, The weight of the mice implanted with EEG electrodes did not differ from that of non-implanted control mice (SD, Student's t test, n = 7). C, Mice implanted with electrodes and non-implanted control mice exhibited the same total duration of inactivity over the whole 24 h light/dark period (p = 0.26) and when every time point was compared (SEM, two-way ANOVA, Sidak's multiple comparison, n = 6), and (D) had equal mean durations of immobility in both the light and dark phases (SD, two-way ANOVA, Sidak's multiple comparison, n = 6). E, Mice implanted with electrodes and non-implanted control mice traveled a comparable distance over the 24 h period (SD, Student's t test, n = 6). F, Representative images of EEG trace in wakefulness, nREM sleep, and REM sleep. G, Baseline percentage time per hour of waking, nREM, and REM sleep (error bars are SEM). The data shown is derived from 48 h recordings posed on the same 24 h timeline. H, Mean percentage time spent in waking, nREM and REM sleep. Mice showed a typical light/dark difference with more wakefulness in the dark period and more nREM sleep and REM sleep in the light period (SD, two-way ANOVA, Sidak's multiple comparison, n = 5, *p < 0.05, ***p < 0.001, ****p < 0.0001). I, Average number of wake-, nREM-, and REM bouts per hour during the light and dark phases. Mice had more waking and nREM bouts during the light period (SD, two-way ANOVA, Sidak's multiple comparison, n = 5, ***p < 0.001, ****p < 0.0001). J, Mean bout duration during the light and dark periods. Mice had long bouts of wakefulness during the dark phase (SD, two-way ANOVA, Sidak's multiple comparison, n = 5, ****p < 0.0001). K, EEG power spectra of wake, nREM sleep, and REM sleep from the first 3 h of the light period (SD; n = 5). ns, non-significant.