动物也做梦？
If animals dream like us, where do they go in their slumber? Jason G Goldman explores how we can peer into the minds of sleeping cats, birds and other creatures.
据BBC报道，要是动物和我们一样也会做梦，它们睡梦中都去哪儿了？杰森·G·戈德曼（Jason G Goldman）研究了如何窥探猫、鸟类和其他动物睡眠中的思想活动的问题。
"Almost all other animals are clearly observed to partake in sleep, whether they are aquatic, aerial, or terrestrial," wrote Aristotle in his workOn Sleep and Sleeplessness. But do other animals dream? On that the Greek philosopher also had an opinion. In The History of Animals, he wrote: "It would appear that not only do men dream, but horses also, and dogs, and oxen; aye, and sheep, and goats, and all viviparous quadrupeds; and dogs show their dreaming by barking in their sleep." His research methods may lack sophistication, but Aristotle may not have been too far off the mark.
“据观察，几乎所有动物都睡觉，无论它们生活在水中、空中还是陆地，”亚里士多德在他的作品《论睡眠与失眠》中写道。可是动物会做梦吗？这位希腊哲学家对这一问题也有自己的观点。他在《动物志》中写道：“似乎不仅人会做梦，马、狗、牛、绵羊、山羊和所有胎生的四足动物都会做梦。通过睡眠中的犬吠可以看出狗在做梦。”他是研究手段也许并不高明，不过亚里士多德的结论可能偏差并不大。
We certainly can't ask animals if they dream, but we can at least observe the evidence that they might. There are two ways in which scientists have gone about this seemingly impossible task. One is to look at their physical behaviour during the various phases of the sleep cycle. The second is to see whether their sleeping brains work similarly to our own sleeping brains.
我们当然不能去问动物它们会不会做梦，但至少可以观察可能证明做梦的证据。科学家们通过两种方式来完成这项看似不可能的任务。一是观察动物在不同睡眠阶段的动作行为。二是研究动物睡眠中的大脑运动是与人类睡眠中的大脑运动相似。
The story of how we worked out how to peer into the minds of sleeping animals begins in the 1960s. Back then, scattered reports began to appear in medical journals describing people acting out movements in their dreams. This was curious, because during so-called REM sleep (rapid eye movement), our muscles are usually paralysed.
上世纪60年代我们就开始探索如何窥探动物睡眠中的思想活动。那时候，医学期刊上开始有零星报道指出人会把梦中的运动表现出来。这是极不寻常的，因为在所谓快速眼动睡眠中，我们的肌肉处于瘫痪状态。
Researchers realised that inducing a similar state in animals could allow them to probe how they dream. In 1965, French scientists Michel Jouvet and J F Delorme found that removing a part of the brainstem, called the pons, from a cat's brain prevented it becoming paralysed when in REM. The researchers called the condition "REM without atonia" or REM-A. Instead of lying still, the cats walked around and behaved aggressively.
研究人员意识到动物身上相似的行为可以让他们探索动物如何做梦。1965年，法国科学家米歇尔·朱维特（Michel Jouvet）和J·F·德罗姆（J F Delorme）发现，如果从猫的脑干中移除一部分叫做脑桥的成分，猫在快速眼动睡眠中就不会转为瘫痪状态。研究人员把这一状态称为“张力缺失的快速眼动”。这种情况下猫不是躺着，而是四处走动而且有攻击性。
This hinted they were dreaming of activities from their waking hours. And studies since have revealed similar behaviour. According to veterinary neurologist Adrian Morrison, who has written a review of this research, cats in REM-A will move their heads as if following stimuli. Some cats also show behaviour identical to predatory attacks, as if they were chasing mice in their dreams. Similar dream activity has been seen in dogs.
这说明猫正梦到自己清醒时的活动。之后的研究揭示了类似的行为。兽医神经学家阿德林·莫里森（Adrian Morrison）写了一篇关于该研究的报告，他说猫在张力缺失的快眼运动中像受到刺激一样摇动头部。有的猫还展示出类似出击捕食一样的行为，好像正在梦中抓老鼠。狗的身上也发现了类似的梦境行为。
Some humans have been found to ‘act out’ their dreams too – if they suffer from a condition called REM Sleep Behaviour Disorder. "Punching, kicking, leaping, and running from the bed during attempted dream enactment are frequent manifestations and usually correlate with the reported imagery," according to the International Classification of Sleep Disorders (ICSD). Injuries are common among these people and those sleeping with them, the ICSD adds.
据发现有的人也会“表现出”自己的梦，因为受到所谓的快眼运动睡眠行为失调症的影响。“在虚拟的睡梦情境中出拳、蹬腿、跳跃或跑下床，这些是常见的表现，而且与报告的心理意象相对应，”国际睡眠失调分类研究显示。这些人经常受伤，还有跟他们一起睡觉的人，该研究补充道。
Physical movement is not the only way of peering into dreams, though. Researchers can now humanely peer into the electrical and chemical activities of brain cells in animals while they sleep. In 2007, MIT scientists Kenway Louise and Matthew Wilson recorded the activity of neurons in a part of the rat brain called the hippocampus, a structure known to be involved in the formation and encoding of memories. They first recorded the activity of those brain cells while the rats ran in their mazes. Then they looked at the activity of the very same neurons while they slept. Louise and Wilson discovered identical patterns of firing during running and during REM. In other words, it was as if the rats were running the maze in their minds while they were snoozing. The results were so clear that the researchers could infer the rats' precise location within their mental dream mazes and map them to actual spots within the actual maze.
不过，运动行为不是窥探梦境的唯一方式。研究人员现在能够以人道的方式窥探动物睡觉时脑细胞的电波和化学活动。2007年，麻省理工大学的科学家肯威·路易（Kenway Louise）和马修·威尔逊（Matthew Wilson）记录下了老鼠大脑中叫做海马体的成分的神经活动，海马体与记忆的形成和编码有关。他们首先记录了老鼠走迷宫时的脑细胞活动。然后观察了老鼠睡眠中同一区域的神经活动。路易和威尔逊发现走迷宫时的发放模式与快速眼动时的发放模式是相同的。换句话说，似乎老鼠睡觉时在脑海里走迷宫。实验结果非常清晰，研究人员甚至可以指出老鼠在脑海中的迷宫具体走到了哪个位置，而且把这些位置标注在了真实的迷宫上。
University of Chicago biologists Amish Dave and Daniel Margoliashlooked into the brains of zebra finches and discovered something similar. These birds are not born with the melodies of their songs hardwired into the brains; instead, they have to learn to sing their songs. When they're awake, the neurons in part of the finches' forebrain called the robutus archistriatalis fire following their singing of particular notes. Researchers can determine which note was sung based on the firing patterns of those neurons. By piecing together the electrical patterns in those neurons over time, Dave and Margoliash can reconstruct the entire song from start to finish.
芝加哥大学的生物学家阿米什·戴夫（Amish Dave）和丹尼尔·马格里亚史（Daniel Margoliash）对斑胸草雀进行研究，获得了类似的发现。这些鸟儿并不是天生就会唱动听的旋律，而是必须通过后天的学习。小鸟清醒时，它们前脑中的一部分神经细胞依据它们唱的具体旋律进行发放活动。研究者可以通过该神经的发放模式判断小鸟唱了哪支曲子。通过拼接该神经一段时间内的电波类型，戴夫和马格里亚史能够从头到尾重现整首曲子。
Later, when the birds were asleep, Dave and Margoliash looked again at the electrical activity in that part of their brains. The firing of those neurons wasn't entirely random. Instead, the neurons fired in order, as if the bird was audibly singing the song, note for note. It might be said that the zebra finches were practising their songs while they slumbered.
当小鸟睡着以后，戴夫和马格里亚史再次观察大脑该区域的电波运动。该神经的发放行为并非完全无序的。相反，该神经有序地发放，就像小鸟在出声唱歌一样，一曲接一曲。可以这么说，斑胸草雀正在睡梦中练习唱歌。
Does the behaviour of cats in science experiments actually qualify as dreaming? Do rats have any subjective awareness that they're running their mazes in their minds while they nap? Do the songbirds realise that they're singing in their sleep? These questions are as hard to answer as the question of consciousness. It's tricky. We humans do not usually realise we're dreaming while we're dreaming, but it becomes clear as soon as we wake up. Do zebra finches remember their dreams as dreamswhen they're shaken out of their sleep? Can they distinguish the real world from the one in their dreams? We can say with a reasonable amount of certainty that the physiological and behavioural features of dreaming in humans have now been observed in cats, rats, birds, and other animals. Yet what it’s actually like to experience a dream if you’re not human remains a mystery.
猫在科学实验中的行为真的算做梦吗？老鼠能意识到自己睡觉时还在脑海中走迷宫吗？草雀能发现自己在睡梦中唱歌吗？这些问题和关于意识的问题一样难以回答。这很难捉摸。人类在睡觉时通常也意识不到自己在做梦，一旦醒来才发现。斑胸草雀从梦中惊醒时，能知道自己的梦只是梦吗？它们能分辨现实世界和梦中的世界吗？我们可以确信地说人类做梦时的生理和行为特征在猫、老鼠、鸟类和其他动物身上也有体现。不过，人类之外的生物做梦时的感受究竟是怎样的，这仍是未解之谜。
京公网安备 11010802032529号