Question

Why can some people sleep through noises like a  honking car or flushing toilet, while others are awakened by the lightest  sound?

To find the answer, sleep researchers at Massachusetts  General Hospital conducted an unusual study of 12 self-described deep sleepers.  After tests confirmed that the healthy volunteers were solid sleepers, they  took part in a three-night study in the university’s sleep laboratory. The  participants spent the night in a big and comfortable room. But the room also  included four speakers positioned near the top of the bed.

During the night, the deep sleepers were  subjected to 14 different recorded sounds, like street traffic, toilets  flushing, and an airplane flying overhead. Next door, the researchers monitored  their sleep patterns and brain waves.

As expected, all of the participants slept  relatively well, but there were differences in how they responded to the noisy  interruptions. Some of the sleepers didn’t wake up even when a sound was  blasted at 70 decibels（分貝）；others were awakened by sounds at 40 or 50  decibels.

The researchers discovered that the difference  in a sleeper’s reaction to noise could be predicted by the level of brain  activity called “sleep spindles（紡錘體）”. A sleep spindle is a burst of high-frequency  brain activity coming from deep inside the brain during sleep. The source of  the spindles is the thalamus（丘腦）, a part of the brain that sends sensory  information to the rest of the cortex（皮層）.

Before the study, the Massachusetts researchers  theorized that the spindles are the brain’s way of preventing sensory  information from passing through the thalamus and waking the rest of the brain  during sleep. They found that sleepers who experienced the most sleep spindles  during the night were also the soundest sleepers and were least likely to be  awakened by noise.

Scientists already know that most people become  lighter sleepers with age, most likely because older people experience less  “slow wave sleep”, which is the deepest stage of sleep. People also produce  fewer sleep spindles as they age. But even when controlling for the stage of  sleep a person was in, the number of sleep spindles still predicted their risk  for awakening because of noise.

More research is needed, but the findings  suggest that a better understanding of sleep spindles could lead to new behavioral  or drug therapies for people with sleep disorders. For example, future studies  may try to determine whether diet, exercise or other behaviors may influence  the number of sleep spindles a person produces during the night.

71. Some participants can sleep well  through loud noises mainly because ________.

A. their brains don’t respond to outside noises.

B. their brains react differently to noises.

C. they adapt too the environment quickly. 

D. they don’t pay attention to the monitors.

72.  Scientists believe that the key to affecting deep sleep is__________.

A. sleep spindles                           B. stages of sleep         

C. sleep disorders                           D.  sensory information

73.  It can be learned from the passage that_____________.

A. The older a deep sleeper becomes, the lighter  his sleep must be.

B. The more “slow wave sleep” one experiences,  the deeper sleep one has.

C. The more frequently a sleeper’s brain works,  the less information it sends.

D. The deeper sleep people have, the more likely  they will be awakened by noise.

74.  From the passage we can predict____________.

A. more factors in influencing sleep spindles  may be discovered.

B. more solid sleepers will take part in  relative experiments.

C. sleep spindles will be applied to change  one’s behaviors.

D. deep sleepers will probably enjoy a more  healthy life.

75.  What is the main idea of the passage?

A. The differences between the deep sleepers and  the light sleepers.

B. The experiments conducted by Massachusetts  General Hospital.

C. The discovery and the importance of “sleep spindles”.

D. The new behaviors or drug therapies for  people with sleep disorders.

Answer 1

【全文翻譯】

為什么有些人睡到像一輛車的噪音或沖洗廁所，而其他人卻被最輕的聲音驚醒？

為了找到答案，麻省總醫(yī)院的睡眠研究人員對12名自稱深睡眠者進行了一項不同尋常的研究。經(jīng)過測試證實健康志愿者是真正的睡眠者，他們參加了大學睡眠實驗室的三晚的研究。參加者在一個舒適的大房間里過夜。但是房間里也有四個揚聲器靠近床的頂部。

在夜間，深睡者受到14種不同的聲音，比如街道交通，廁所沖水，還有一架飛機從頭頂飛過。隔壁，研究人員監(jiān)測他們的睡眠模式和腦電波。

正如預(yù)期的那樣，所有參與者都睡得比較好，但他們對嘈雜干擾的反應(yīng)有差異。有些人沒有醒來，甚至當一聲爆炸在70分貝（分貝）；人被吵醒的聲音在40或50分貝。

研究人員發(fā)現(xiàn)，睡眠者的反應(yīng)的差異可由噪聲水平的大腦活動被稱為“睡眠紡錘波的預(yù)測（紡錘體）”。睡眠紡錘波是一種高頻腦活動，來自于睡眠時大腦深處的活動。錠的來源是丘腦（丘腦），那將感覺信息的其余部分的皮層的大腦的一部分（皮層）。

在這項研究之前，馬薩諸塞州研究人員推測紡錘波是大腦阻止感覺信息通過丘腦并在睡眠中喚醒大腦其余部分的一種方式。他們發(fā)現(xiàn)，那些經(jīng)歷過最睡眠紡錘波夜間睡眠也最完整的枕木，是最有可能被嚇醒了。

科學家已經(jīng)知道，大多數(shù)人隨著年齡的增長而變得更輕，很可能是因為老年人經(jīng)歷了“慢波睡眠”，這是睡眠最深的階段。隨著年齡的增長，睡眠紡錘波也越來越少。但是即使控制了睡眠階段，睡眠紡錘波的數(shù)量仍然預(yù)示著由于噪音而醒來的危險。

需要更多的研究，但研究結(jié)果表明，更好地了解睡眠紡錘波可能會導(dǎo)致新的行為或藥物治療睡眠障礙的人。例如，未來的研究可能會試圖確定飲食、運動或其他行為是否會影響一個人夜間睡眠的數(shù)量。

71—75 BABAC