Sleep Lets Brain File Memories To sleep. Perchance to file? Findings published online this week by the proceedings of the Na

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问题                   Sleep Lets Brain File Memories
    To sleep. Perchance to file? Findings published online this week by the proceedings of the National Academy of Sciences further support the theory that the brain organizes and stows memories formed during the day while the rest of the body is catching zzz’s.
    Gyorgy Buzsaki of Rutgers University and his colleagues analyzed the brain waves of sleeping rats and mice. Specifically, they examined the electrical activity emanating(散发) from the somatosensory (耳、目、口等以外的)neocortex(新大脑皮层) (an area that processes sensory information) and the hippocampus(海马) , which is a center for learning and memory. The scientists found that oscillations in brain waves from the two regions appear to be intertwined. So-called sleep spindles (bursts of activity from the neocortex) were followed tens of milliseconds later by beats in the hippocampus known as ripples. The team posits that this interplay between the two brain regions is a key step in memory consolidation.
    A second study, also published online this week by the proceedings of the National Academy of Sciences, links age-associated memory decline to high glucose levels.
    Previous research had shown that individuals with diabetes (糖尿病,多尿症) suffer from increased memory problems. In the new work, Antonio Convit of New York University School of Medicine and his collaborators studied 30 people whose average age was 69 to investigate whether sugar levels, which tend to increase with age, affect memory in healthy people as well. The scientists administered recall tests, brain scans (细看,审视,浏览,扫描) and glucose tolerance tests, which measure how quickly sugar is absorbed from the blood by the body’s tissues. Subjects with the poorest memory recollection, the team discovered, also displayed the poorest glucose tolerance. In addition , their brain scans showed more hippocampus shrinkage than those of subjects better able to absorb blood sugar.
    "Our study suggests that this impairment(损害、损伤) may contribute to the memory deficits (赤字、不足额) that occur as people age. " Convit says. "And it raises the intriguing possibility that improving glucose tolerance could reverse some age-associated problems in cognition. " Exercise and weight control can help keep glucose levels in check(阻止、制止) , so there may be one more reason to go to the gym.  
What is the relation of memory to glucose tolerance, as is indicated by a research mentioned in paragraph 4?

选项 A、People with poor memory have high glucose tolerance.
B、People with good memory have low glucose tolerance.
C、Memory level has nothing to do with glucose tolerance.
D、The poorer the memory, the poorer glucose tolerance.

答案D

解析 第四段倒数第二句提供了答案。
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