Mascetti Gian G, Rugger Marina, Vallortigara Giorgio, Bobbo Daniela
Department of General Psychology, University of Padova, Via Venezia 8, 35131, Padova, Italy.
Exp Brain Res. 2007 Jan;176(1):70-84. doi: 10.1007/s00221-006-0595-3. Epub 2006 Jul 28.
During sleep, domestic chicks (Gallus gallus) show brief and transient periods during which one eye is open while the other remains shut. Electrophysiological recordings showed that the hemisphere contra-lateral to the open eye exhibited an EEG with fast waves typical of wakefulness, whereas the hemisphere contra-lateral to the closed eye exhibited an EEG typical of slow wave sleep. We investigated the pattern of monocular-unihemispheric sleep (Mo-Un sleep; i.e. selective preferential closure/opening of the left or right eye during sleep) following three types of visual learning tasks. The first group of chicks was submitted to a colour discrimination task (1), the second group to a spatial discrimination task with colour as a conspicuous, but irrelevant, cue (2), the third group to a spatial task without colour cue. After learning, the amount of binocular sleep and Mo-Un sleep patterns were recorded. The first and the second group of chicks exhibited more right Mo-Un sleep (right eye-closure/left unihemispheric sleep), suggesting that this pattern may be connected with prevalent engagement of left hemisphere during training trials. The third group showed a significant more left Mo-Un sleep (left eye-closure/right unihemispheric sleep) which would be associated with a prevalent engagement of right hemisphere during trials. Chicks of the control groups, did not learn the task, but were submitted to an equal number of trials. Controls of tasks 1 and 2 showed more left Mo-Un sleep suggesting a dominance of right hemisphere during exposure trials. Instead there was no eye-closure bias in controls of task 3, suggesting an absence of hemispheric dominance during trials. It is suggested that the Mo-Un sleep pattern may be a type of local sleep associated with a process of functional recovery in the hemisphere which was mainly engaged during training trials.
在睡眠过程中，家鸡（原鸡）会出现短暂的瞬态期，期间一只眼睛睁开而另一只眼睛保持闭合。电生理记录显示，与睁开眼睛相对的半球呈现出具有清醒典型快波的脑电图，而与闭合眼睛相对的半球呈现出慢波睡眠典型的脑电图。我们研究了三种视觉学习任务后单眼-单侧半球睡眠（Mo-Un睡眠；即睡眠期间左眼或右眼选择性优先闭合/睁开）的模式。第一组小鸡接受颜色辨别任务（1），第二组接受以颜色为显著但无关线索的空间辨别任务（2），第三组接受无颜色线索的空间任务。学习后，记录双眼睡眠量和Mo-Un睡眠模式。第一组和第二组小鸡表现出更多的右侧Mo-Un睡眠（右眼闭合/左侧单侧半球睡眠），这表明这种模式可能与训练试验期间左半球的普遍参与有关。第三组表现出显著更多的左侧Mo-Un睡眠（左眼闭合/右侧单侧半球睡眠），这与试验期间右半球的普遍参与有关。对照组的小鸡没有学会任务，但接受了相同数量的试验。任务1和2的对照组表现出更多的左侧Mo-Un睡眠，表明在暴露试验期间右半球占主导。相反，任务3的对照组没有闭眼偏向，表明试验期间没有半球优势。有人认为，Mo-Un睡眠模式可能是一种局部睡眠，与训练试验期间主要参与的半球的功能恢复过程有关。
