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  3. Scientists have learned how to discover what you are dreaming about while you sleep. A team of researchers led by Yukiyasu Kamit

Scientists have learned how to discover what you are dreaming about while you sleep. A team of researchers led by Yukiyasu Kamit

admin2016-06-30  57
问题     Scientists have learned how to discover what you are dreaming about while you sleep. A team of researchers led by Yukiyasu Kamitani used functional neuroimaging to scan the brains of three people as they slept, simultaneously recording their brain waves using electroencephalography(EEG).
    The researchers woke the participants whenever they detected the pattern of brain waves associated with sleep onset, asked them what they had just dreamed about, and then asked them to go back to sleep. This was done in three-hour blocks, and repeated between seven and ten times, on different days, for each participant. During each block, participants were woken up ten times per hour. Each volunteer reported having visual dreams six or seven times every hour, giving the researchers a total of around 200 dream reports.
    Most of the dreams reflected everyday experiences, but some contained unusual content, such as talking to a famous actor. The researchers extracted key words from the participants’ verbal reports, and picked 20 categories—such as "car", "male", "female" and "computer"—that appeared most frequently in their dream reports. Kamitani and his colleagues then selected photos representing each category, scanned the participants’ brains again while they viewed the images, and compared brain activity patterns with those recorded just before the participants were woken up.
    The researchers analyzed activity in brain areas V1, V2 and V3, which are involved in the earliest stages of visual processing and encode basic features of visual scenes, such as contrast and the orientation of edges. They also looked at several other regions that are involved in higher order visual functions, such as object recognition.
    In 2008, Kamitani and his colleagues reported that they could decode brain activity associated with the earliest stages of visual processing to reconstruct images shown to participants. Now, they have found that activity in the higher order brain regions could accurately predict the content of the participants’ dreams. "We built a model to predict whether each category of content was present in the dreams," says Kamitani. "By analyzing the brain activity during the nine seconds before we woke the subjects, we could predict whether a man is in the dream or not, for instance, with an accuracy of 75 -80%. " The findings, presented at the annual meeting of the Society for Neuroscience, suggest that dreaming and visual perception share similar neural representations in the higher order visual areas of the brain.
    Kamitani’s team are now trying to collect the same kind of data from the rapid eye movement(REM)stage of sleep, which is also associated with dreaming. This is more challenging but worth well. "Knowing more about the content of dreams and how it relates to brain activity may help us to understand the function of dreaming. "
Compared with the 2008 research, the new one has improved in the following aspects EXCEPT______.
选项 A、accuracy
B、universality
C、definitude
D、profundity
答案B
解析 细节题。由题干可定位至第五段。该段第一句简要回顾了2008年相关研究的情况，当时的研究可对初期影像处理的大脑活动进行解码并重塑参与者所见的形象。从第二句起，原文开始介绍新研究的进展。由原文可知，新研究并没有将研究发现推而广之到其他相关领域，因此在普遍性方面没有发展，故[B]为答案。根据第五段第二句至第五句内容，在原有研究的基础上，新研究建立了一个模式，可准确预测梦境的内容，还发现了梦境与形象感知在脑部的联系。可见新研究在准确性、确切程度和深度方面都有了进展，故排除[A]、[C]和[D]。
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