PLoS One:鸵鸟独特睁眼睡眠模式
PLoS One · 2011/08/31
研究人员预计鸵鸟的脑电波看起来应该与其他的鸟类和哺乳动物类似,其周期应该介于两种模式——深度睡眠和快速眼动睡眠(REM)之间。

与流行的看法相反,鸵鸟并不会将脑袋埋在沙堆中睡觉。

事实上,就外表来看,它们似乎从来就不曾睡觉——鸵鸟的眼睛总是睁开的,尽管它们似乎偶尔也会打瞌睡。

为了更多地了解这种与众不同的大鸟的睡眠模式,德国维森市马普学会鸟类研究所的动物学家John A. Lesku和同事在南非捕捉了6只鸵鸟,并使用数据记录仪在它们打瞌睡的时候测量了鸵鸟的脑电波模式。

研究人员预计鸵鸟的脑电波看起来应该与其他的鸟类和哺乳动物类似,其周期应该介于两种模式——深度睡眠和快速眼动睡眠(REM)之间。

当记录仪显示鸵鸟处于深度睡眠中时,这种鸟类看上去是完全警醒的。但是当它们进入另一个睡眠周期后,它们的脑袋便开始下垂。

研究人员在本周出版的《科学公共图书馆—综合》(PLoS ONE)上报告说,这第二种脑电波形式并非传统意义上的快速眼动睡眠,而是快速眼动睡眠和深度睡眠模式罕有的一种混合体。

唯一一种表现出这种模式的动物是鸭嘴兽,这是一种古老的产卵哺乳动物,即单孔目动物的一员。

由于鸵鸟也是一种非常古老的鸟类,因此这种相似性表明,快速眼动睡眠和深度睡眠之间的分离可能是“最近”才从鸟类和哺乳动物中进化而来的。人们只能猜测,是否鸵鸟也和鸭嘴兽做着同样的美梦。

生物探索推荐英文论文摘要:

Ostriches Sleep like Platypuses

Mammals and birds engage in two distinct states of sleep, slow wave sleep (SWS) and rapid eye movement (REM) sleep. SWS is characterized by slow, high amplitude brain waves, while REM sleep is characterized by fast, low amplitude waves, known as activation, occurring with rapid eye movements and reduced muscle tone. However, monotremes (platypuses and echidnas), the most basal (or ‘ancient’) group of living mammals, show only a single sleep state that combines elements of SWS and REM sleep, suggesting that these states became temporally segregated in the common ancestor to marsupial and eutherian mammals. Whether sleep in basal birds resembles that of monotremes or other mammals and birds is unknown. Here, we provide the first description of brain activity during sleep in ostriches (Struthio camelus), a member of the most basal group of living birds. We found that the brain activity of sleeping ostriches is unique. Episodes of REM sleep were delineated by rapid eye movements, reduced muscle tone, and head movements, similar to those observed in other birds and mammals engaged in REM sleep; however, during REM sleep in ostriches, forebrain activity would flip between REM sleep-like activation and SWS-like slow waves, the latter reminiscent of sleep in the platypus. Moreover, the amount of REM sleep in ostriches is greater than in any other bird, just as in platypuses, which have more REM sleep than other mammals. These findings reveal a recurring sequence of steps in the evolution of sleep in which SWS and REM sleep arose from a single heterogeneous state that became temporally segregated into two distinct states. This common trajectory suggests that forebrain activation during REM sleep is an evolutionarily new feature, presumably involved in performing new sleep functions not found in more basal animals.

全文阅读:

PLoS One:鸵鸟独特睁眼睡眠模式.pdf

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