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 [p?'t?ɑ:ns] adv. 偶然;可能
online ['?nlain] n. 在線的
stow [st?u] vt. 貯藏，堆裝
emanate ['em?neit] vi. 發(fā)源
somatosensory [,s?um?t?'sens?ri] adj. 體覺的
neocortex [,ni:?u'k?:teks] n. 新(大腦)皮質(zhì)
oscillation [,?si'lei??n] n. 振蕩
intertwine [,int?'twain] v. 纏繞
spindle ['spindl] n. 紡錘體
ripple ['ripl] n. 波動，脈動
diabetes [,dai?'bi:ti:z] n. 糖尿病
recollection [,rek?'lek??n] n. 回憶
shrinkage ['?ri?kid?] n. 收縮
impairment [im'p??m?nt] n. 損傷
intrigue [in'tri:ɡ] n. 引起。。。興趣(或好奇心)
cognition [k?ɡ'ni??n] n. 認識
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: (科學文獻、會議文獻)匯編，常用復數(shù)形式。
4. zzz：(擬聲詞)打鼾聲
5. Rutgers University：美國新澤西州立大學 (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的認知問題。
15. keep glucose levels in check：限制葡萄糖水平。 in check：在控制中，被阻止。