Sleep patterns of the volcano mouse (Neotomodon alstoni alstoni).

Sleep-waking patterns of the volcano mouse were studied under laboratory conditions. This rodent exhibits four states of vigilance: active wakefulness (Aw), quiet wakefulness (Qw), slow-wave sleep (SWS), and paradoxical (PS), or rapid-eye movement (REM) sleep. These states present, in general, the classic mammalian electrophysiological patterns. Although sleep periods were distributed at any time of the nychthemeral cycle, they showed the tendency to concentrate between 0800 and 2000 hours. The volcano mouse may be considered as a "good" sleeper, because it shows a relatively high percentage of sleep from the total recording time (TRT). Slow-wave sleep occupied 64.54 +/- 8.84% (mean +/- SD) of the total recording time, while 7.56 +/- 1.31% corresponded to rapid-eye movement sleep. The average duration of the rapid-eye movement sleep phase was 126.48 +/- 17.79 s, exhibiting an average recurrence of 49 +/- 9.28 phases throughout the nychthemeral cycle. Mean duration of the sleep cycle was 9.23 +/- 2.36 min. Quantitative data of the volcano mouse sleep may be considered adequate for its body size and characteristic of an animal which sleeps in secure places under free-living conditions.