Lyamin O I, Mukhametov L M, Siegel J M, Nazarenko E A, Polyakova I G, Shpak O V
Severtsov Institute of Ecology and Evolution, 33 Leninsky Prospect, Moscow, Russia.
Behav Brain Res. 2002 Feb 1;129(1-2):125-9. doi: 10.1016/s0166-4328(01)00346-1.
We recorded electroencephalogram (EEG) and simultaneously documented the state of both eyelids during sleep and wakefulness in a sub-adult male white whale over a 4-day-period. We showed that the white whale was the fifth species of Cetaceans, which exhibits unihemispheric slow wave sleep. We found that the eye contralateral to the sleeping hemisphere in this whale was usually closed (right eye, 52% of the total sleep time in the contralateral hemisphere; left eye, 40%) or in an intermediate state (31 and 46%, respectively) while the ipsilateral eye was typically open (89 and 80%). Episodes of bilateral eye closure in this whale occupied less than 2% of the observation time and were usually recorded during waking (49% of the bilateral eye closure time) or low amplitude sleep (48%) and rarely in high amplitude sleep (3%). In spite of the evident overall relationship between the sleeping hemisphere and eye state, EEG and eye position in this whale could be independent over short time periods (less than 1 min). Therefore, eye state alone may not accurately reflect sleep state in Cetaceans. Our data support the idea that unihemispheric sleep allows Cetaceans to monitor the environment.
我们在一头亚成年雄性白鲸身上进行了为期4天的记录，期间记录了其脑电图（EEG），并同时记录了睡眠和清醒状态下双眼睑的状态。我们发现白鲸是第五种表现出单侧慢波睡眠的鲸类动物。我们发现，在这头鲸鱼中，与睡眠半球对侧的眼睛通常是闭合的（右眼，占对侧半球总睡眠时间的52%；左眼，占40%）或处于中间状态（分别为31%和46%），而同侧眼睛通常是睁开的（分别为89%和80%）。这头鲸鱼双眼闭合的时间占观察时间不到2%，通常记录于清醒时（占双眼闭合时间的49%）或低振幅睡眠时（48%），很少出现在高振幅睡眠时（3%）。尽管睡眠半球与眼睛状态之间存在明显的总体关联，但在这头鲸鱼中，脑电图和眼睛位置在短时间内（不到1分钟）可能是独立的。因此，仅眼睛状态可能无法准确反映鲸类动物的睡眠状态。我们的数据支持了单侧睡眠使鲸类动物能够监测环境这一观点。
