Percentage of time spent in non-REM sleep and REM sleep and mean numbers and mean durations of full-length and aborted REM sleep bouts for rats that were allowed 1 or 2 h recovery sleep after 2 h REM sleep restriction (n = 10)
| Behavioral stages | 1 h recovery rats (n = 5) | 2 h recovery rats (n = 5) | |
|---|---|---|---|
| The first 1 h period | The second 1 h period | ||
| Non-REM sleep (%) | 60.1 ± 1.4 | 61.3 ± 1.5 | 62.1 ± 1.2 |
| REM sleep (%) | 26.1 ± 0.8 | 25.7 ± 1.1 | 19.1 ± 0.6* |
| Mean numbers of full-length REM bouts | 8.1 ± 0.9 | 7.8 ± 0.74 | 5.6 ± 0.5* |
| Mean durations of full-length REM bouts (min) | 1.78 ± 0.11 | 1.751.81 ± 0.1 | 1.81 ± 0.09 |
| Mean numbers of aborted REM episodes | 6.5 ± 0.7 | 6.1 ± 0.8 | 4.2 ± 0.5 |
| Mean durations of aborted REM episodes (s) | 11.3 ± 3.01 | 14.9 ± 1.9 | 18.9 ± 2.7 |
In 1 h recovery rats, percentage of non-REM sleep and percentage of REM sleep were calculated for a 1 h recording period before the rats were killed. In 2 h recovery animals, percentage of non-REM sleep and percentage of REM sleep were calculated for both the first and the second hours of the 2 h recording period before the rats were killed. Differences in percentage of sleep stages between the groups of REM sleep recovery rats were assessed with an unpaired t test; comparison was done between the values of the last 1 h periods before the rats were killed. No significant difference was seen in percentage of non-REM sleep, whereas percentage of REM was significantly different between the groups (t(8) = 7.3; *p < 0.001). The 2 h recovery rats had significantly fewer full-length REM sleep bouts during the second hour versus the first hour of recovery sleep (t(8) = 3.9; *p < 0.001).