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 University5 and his colleagues analyzed the brain waves of sleeping rats and mice. Specifically, they examined the electrical activity emanating from6 the somatosensory neocortex (an area that processes sensory information) and the hippocampus, 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 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 administered11 recall tests, brain scans 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 impairment12 may contribute to the memory deficits13 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.14" Exercise and weight control can help keep glucose levels in check15, so there may be one more reason to go to the gym.

　　詞匯：

　　perchance adv. 偶然；可能

　　online n. 在線的

　　stow vt. 貯藏，堆裝

　　emanate vi. 發(fā)源

　　somatosensory adj. 體覺的

　　neocortex n. 新（大腦）皮質(zhì)

　　oscillation n. 振蕩

　　intertwine v. 纏繞

　　spindle n. 紡錘體

　　ripple n. 波動，脈動

　　diabetes n. 糖尿病

　　recollection n. 回憶

　　shrinkage n. 收縮

　　impairment n. 損傷

　　intrigue n. 引起。。。興趣（或好奇心）

　　cognition n. 認(rèn)識

　　注釋：

　　1. file memories：歸檔并儲存記憶。 file：意為 "to put or keep (papers,etc. ) in useful order for storage or reference"（把…歸檔）。

　　2. To sleep. Perchance to file? ：從莎士比亞筆下哈姆雷特的獨白中的名句" To sleep: perchance to dream. "改編而來。

　　3. the Proceedings: (科學(xué)文獻(xiàn)、會議文獻(xiàn))匯編，常用復(fù)數(shù)形式。

　　4. zzz：（擬聲詞）打鼾聲

　　5. Rutgers University：美國新澤西州立大學(xué) (the State University of New Jersey)。

　　6. emanating from：發(fā)源于。

　　7. neocortex：新(大腦)皮質(zhì)，尤指大的高等哺乳動物大腦中新生長的部分，也叫做 neopallium。neo-：前縀，意思是"新的"。

　　8. thehippocampus：大腦側(cè)面腦室壁上的隆起物，也稱"海馬狀突起"，在泛記過程中起主要作用。

　　9. tens of milliseconds：幾十毫秒

　　10. age-associated memory decline：與年齡相關(guān)的記憶衰退

　　11. administer：實施

　　12. this impairment：指上句中 hippocampus shrinkage.

　　13. memory deficits：記憶衰退

　　14. … the intriguing possibility that improving glucose tolerance could reverse some age-associated problems in cognition：令人興奮的可能性，即不斷改善葡萄糖容許量可以完全改變對某些與年齡相關(guān)的認(rèn)知問題。

15. keep glucose levels in check：限制葡萄糖水平。 in check：在控制中，被阻止。
練習(xí)：

　　1. Which of the following statements is nearest in meaning to the sentence "To sleep. Perchance to file?"? A Does brain arrange memories in useful order during sleep?

　　B Does brain have memories when one is sleeping?

　　C Does brain remember files after one falls asleep?

D Does brain work on files in sleep?

　　2. What is the result of the experiment with rats and mice carried out at Rutgers University?

　　A The electrical activity is emanating from the somatosensory neocortex.

　　B Oscillations in brain waves are from hippocampus.

　　C Somatosensory neocortex and hippocampus work together in memory consolidation.

D Somatosensory neocortex plays it primary role in memory consolidation.

　　3. What is the relation of memory to glucose tolerance, as is indicated by a research mentioned in paragraph 4?

　　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.

　　4. In what way is memory related to hippocampus shrinkage?

　　A There is no relation between memory and hippocampus shrinkage.

　　B The more hippocampus shrinks, the poorer one's memory.

　　C The more hippocampus shrinks, the better one's memory.

D The less hippocampus shrinks, the poorer one's memory.

　　5. According to the last paragraph, what is the ultimate reason for going to the gym?

　　A To prevent hippocampus shrinkage.

　　B To control weight.

　　C To exercise.

　　D To control glucose levels.

　　答案與解釋 :

　　1. A文章第一段告訴我們，科學(xué)新發(fā)現(xiàn)進(jìn)一步支持了一種理論，即，當(dāng)人體進(jìn)入睡眠狀態(tài)時，大腦對在白天形成的記憶進(jìn)行組織和儲存。 To sleep. Perchance to file?見注釋 1和注釋 2。

　　2. C 第二段告訴我們，科學(xué)家分析了老鼠的腦電波，尤其是從 somatosensory neocortex和 hippocampus兩個區(qū)域發(fā)出的腦電波。該段是后兩句指出，這兩個大腦區(qū)域的活動是互相作用的。第二段并沒有說 somatosensory neocortex或 hippocampus起主導(dǎo)作用。

　　3. D 該段倒數(shù)第二句提供了答案。

　　4. B 第四段的后一句中 their brain scans，指上句中的 subjects

5. D 鍛煉身體和體重控制能保持葡萄糖水平，閑此，去健身房就有了另外一個理由。