贴墙功补肾原理:梦中恍似梦外游

无论我们是在坠落或是飞翔、误导或是驾车，梦中的活动在彼时都想现实生活中那样真切。而且似乎我们的大脑也是这样认为的。研究人员发现，当我们在梦境中活动时，大脑一边想象梦中事物，一边按照我们现实世界中的方式展开思维。

Because we tend to forget our dreams as soon as we wake up, researchers know little about how our minds create them. Neuroscientists Martin Dresler and Michael Czisch, both of the Max Planck Institute of Psychiatry in Munich, Germany, and their colleagues wanted to find a way to use brain-imaging techniques to watch what people were doing in their dreams. To interpret these images of the dreaming brain, however, they would first have to know how the brain looks when it is performing a certain task in the dream—a difficult challenge because most dreamers can't control what they're doing. 

由于我们刚醒来时很容易忘记做过的梦，研究人员对于我们的意识如何工作知之甚少。两位来自德国慕尼黑马克思普朗克学院的神经学家Martin Dresler和Michael Czish和他们的同事试图找到一种运用大脑成像技术来观察人们梦中活动的方法，不过，他们必须得知道大脑在梦中执行某一种工作时它看起来是什么样子的。由于大多数做梦的人不能控制他们的梦境，这对于科学家们来说一个艰巨的挑战。

Very rarely, however, dreamers experience a phenomenon known as lucid dreaming, in which a sleeper is aware that he or she is dreaming and has some level of control over actions in the dream. "About half of people have had a lucid dream, Dresler says, but "very few have them on a regular basis." Certain people can learn to dream lucidly more often. The training involves techniques such as writing down dreams and committing to remember that you're dreaming when you see a certain theme, such as a flying cow, says neuroscientist Daniel Erlacher of the University of Bern, who was not involved in the current research. 

峰回路转的是，做梦者很罕见地会经历过一种叫做“清醒梦境”的现象，这是一种做梦者能够意识到他或她正在做梦并且能够对梦中行为作出控制的过程。“大约一半的人有过‘清醒梦境’”Dresler指出“不过只有很少一部分人经常经历这种情况。”某些人甚至能学会如何让“清醒梦境”出现得更频繁些。伯尔尼大学的神经学家Daniel Erlacher指出这种训练包括记录梦境并且致力于每当看到一个特定情景——比如一头飞牛，就能够指出这是在做梦的能力，他目前不在这项研究之中。

Dresler and Czisch recruited six people who had been trained in lucid dreaming, instructed them to dream that they were clenching either their left or their right hand, and then let them fall asleep in a brain scanner. Once the sleepers were dreaming and lucid, they let the researchers know by moving their eyes from left to right twice. The researchers checked the volunteers' brain activity patterns to make sure they really were in the dream phase of sleep known as rapid eye movement. The team then recorded brain activity using either functional magnetic resonance imaging (fMRI), which shows high-resolution images of brain activity throughout the brain, or near-infrared spectroscopy (NIRS), which shows activity on the surface of the brain.

Dresler和Czisch招募了六个受过“清醒梦境”训练的人，指导他们去梦见他们正在紧握自己的左手或右手，然后让他们在一台大脑扫描仪中入睡。一旦这些睡眠中的人们正在做梦并处于“清醒梦境”，他们就会向研究人员展示从左向右转动眼球两次。研究人员通过检查志愿者脑部活动样式以确认他们正在所谓“快速眼动”的睡眠阶段。小组接着运用展示大脑高分辨图像的机能性磁共振成像（FMRI）和展示大脑表层活动的红外光谱法来记录大脑活动情况。

Only two of the subjects were able to have lucid dreams in the noisy scanners. But in each of them, one in fMRI and one in NIRS, the researchers saw the area of the motor cortex that controls the left hand light up in the same way as in someone who was awake. The subjects were able to perform the task in two different dreams each, the researchers report online today in Current Biology. That suggests that "dreams are not just represented as a visual scene" like watching a movie, Dresler says, but involve the whole body.

结果只有两个被试能够在吵闹的扫描器中找到自己的“清醒梦境”。但是分别在FMRI和NIRS中，研究人员发现控制左右手的大脑运动皮层处的图像和清醒时一样发亮。今天研究人员在《当代生物》在线报告称，被试能够在两个不同的梦中完成任务，从而显示了“梦不仅仅被表达为一种视觉场景”。就像观看一场电影，Dresler说，梦的活动包括整个身体。

"It's a clever use of that patient population," says neurologist Allen Braun of the National Institute on Deafness and Other Communication Disorders in Bethesda, Maryland. He says it's interesting that although the motor cortex, which controls movement itself, was active, the midline area of the brain, which is known to be activated when people are making a decision whether to move a limb, was not active in the lucid dreamer whose brain was imaged with fMRI. "They must know they're not really moving," he says. Although the researchers imaged only two subjects, Braun says that they have done "more than enough" to show that these two brain-imaging techniques can read lucid dreamers' dreams. 

“这是一个对于特殊人群的智慧的应用”，来自马里兰州贝塞斯达的国家听力与交流障碍研究中心的神经学家Allen Braun说道。他表示，虽然控制运动本身的运动皮层是活跃的，但有趣的是，当人们决定是否要移动四肢时，大脑中部区域理应被激活，可是在“清醒梦境”的情况下，FMRI显示这部分区域并不活跃。即使研究人员只记录到两个被试的大脑图像，Braun表示他们已经“足够”阐释了两种脑部成像技术能够记录“清醒梦境”者的梦境。

"It's a very impressive work," Erlacher says, particularly given the difficulty of getting someone to dream lucidly in a noisy scanner. To strengthen their findings, the authors plan to recruit more lucid dreamers to determine whether the brain responds similarly in everyone. And they hope to find out what happens when their dreamers perform more complex tasks such as walking, speaking, or even flying, which would help researchers interpret dreams and understand how and why the mind creates them.

“这是一个令人影响深刻的研究。”Erlacher说，尤其在嘈杂的扫描器中让一个人进入清醒梦境十分困难。为了进一步证实他们的发现，作者计划招募更多的清醒梦境者从而判断是否对于所有人大脑都是如此反应的。并且他们希望看到做梦的人在完成更复杂的工作——比如走路、说话甚至飞行时——大脑是怎么工作的，这会帮助研究人员解释梦并且理解为什么意识创造了它们。