第三篇：睡眠 SLEEP
原文：
Historically, it was difficult to study sleep. Not much can be gleaned fromobserving recumbent persons and questionnaires are no use, because peopleremember little of their experience during sleep. The breakthrough came in the1950’s with electroencephalogram (EEG) recordings of brain electrical activity,when it was confirmed that sleep is anything but dormant.
We need sleep for biological restoration. It promotes cell growth,regeneration and memory consolidation. By shutting down most of the body’s machinery,resources can be focused on repairing damage and development. When people aredeprived of sleep for any reason, there is deterioration in performance,particularly on tasks requiring concentration, and eventually, behaviourbecomes shambolic. The individual becomes progressively incoherent andirritable and, after a few days, may experience delusions and hallucinations.The disruptive effects of sleep deprivation have even been successfully used asa basis of persuasion in interrogation.
A vital part of sleep is dreaming, which happens most intensively duringrapid eye movement (REM) sleep. We typically spend more than two hours eachnight dreaming, though this is often spread over four or five separate periods.Infants spend up to 50 per cent of their sleep time in REM sleep, which isunderstandable when one realises that REM sleep is the time used for braindevelopment, as well as learning, thinking, and organising information. Ifpeople are woken when REM sleep commences, depriving them specifically ofdream-sleep, the proportion of REM sleep increases once they fall asleep againto make up what was lost. This suggests that REM sleep is an essential aspectof sleep.
Sleep and sleep-related problems play a role in a large number of humandisorders and affect almost every field of medicine. For example, problems likea stroke tend to occur more frequently during the night and early morning, dueto changes in hormones, heart rate, and other characteristics associated withsleep. Sleep also affects some kinds of epilepsy in complex ways. REM sleepseems to help prevent seizures that begin in one part of the brain fromspreading to other brain regions, while deep sleep may promote the spread ofthese seizures. Sleep deprivation can also trigger seizures in people with sometypes of epilepsy.
The neurons that control sleep interact strongly with the immune system. Asanyone who has had the flu knows, infectious diseases tend to make people feelsleepy. This probably happens because cytokines, chemicals produced whilefighting an infection, are powerful sleep-inducing substances. Sleep helps thebody conserve energy that the body’s immune system needs to mount an attack.
Sleeping problems occur in almost all people with mental disorders,including those with depression and schizophrenia. People with depression, forexample, often awaken in the early hours of the morning and find themselvesunable to get back to sleep. The amount of sleep a person gets also stronglyinfluences the symptoms of mental disorders. Sleep deprivation is an effectivetherapy for people with certain types of depression, while it can actuallycause depression in other people. Extreme sleep deprivation can lead to aseemingly psychotic state of paranoia and hallucinations in otherwise healthypeople, and disrupted sleep can trigger episodes of mania in people with manicdepression.
Sleeping problems are common in many other disorders as well, includingAlzheimer’s disease, stroke, cancer, and head injury. These sleeping problemsmay arise from changes in the brain regions and neurotransmitters that controlsleep, or from the drugs used to control symptoms of other disorders. Inpatients who are hospitalised or who receive round-the-clock care, treatmentschedules or hospital routines also may disrupt sleep. The old joke about apatient being awakened by a nurse so he could take a sleeping pill contains agrain of truth. Once sleeping problems develop, they can add to a person’simpairment and cause confusion, frustration, or depression. Patients who areunable to sleep also notice pain more and may increase their requests for painmedication. Better management of sleeping problems in people who have a varietyof disorders could improve the health of these patients and their quality oflife.
Insomnia is a widespread affliction. It is linked with conditions such asdepression and chronic pain, but occurs also in otherwise healthy people. It isoften due to temporary life circumstances, like trouble at work or anticipationof an exciting event, however, some people just have difficulty sleepingregardless of circumstances. What is interesting is that complaints ofsleeplessness are often exaggerated, because people remember more easily thetimes they are awake during the night than the times they are asleep. Wheninsomniacs are observed in a sleep lab, their EEG records often suggest thattheir sleep pattern is fairly normal, even though in the morning they maintainthey hardly slept a wink. Various devices for monitoring one’s own sleeppatterns are now marketed, for example mobile phone apps connected withforehead electrodes.
The fact that a third of our life is spent in sleep would, in itself, besufficient justification for studying it scientifically. The discovery that itis not just a passive state, but a highly active process of profound biologicaland psychological importance, has led to great efforts in recent decades tofurther our understanding of it. Despite that, we are far from unravelling allof sleep’s mysteries.
Questions 1-7
Complete the notes below.
Write NO MORE THAN TWO WORDS for each answer.
Write your answers in boxes 1-7 on your answer sheet.
Sleep study only advanced after the electroencephalogram started to beused.
Sleep is used to restore the body and cells, and strengthen the(1)......................
With little sleep, people operate worse, especially when(2)...................... is needed.
The effects of sleep deprivation can be severe and have been used ininterrogations.
REM sleep is when dreaming occurs; important especially for(3)......................, who need a lot of REM sleep for their brains.
If REM sleep is lost, the body increases the (4)......................ofREM sleep in the next sleep to make it up.
Strokes are more common during or after sleep, and(5)...................... and other seizures can both be caused and preventedby sleep.
Sleep is closely associated with the (6)......................, ascytokines produced while the body fights infectious disease induce sleepiness;sleeping when sick helps people save the (7)...................... to fightinfections.
Questions 8-13
Do the following statements agree with the information given in the text?
In boxes 8-13 on your answer sheet write:
TRUE if thestatement agrees with the information
FALSE if the statementcontradicts the information
NOT GIVEN if there is no informationon this
8. A lack of sleep can both help and hinder people suffering fromdepression.
9. Better sleep routines can help people who suffer from Parkinson’sdisease.
10. People who are sleep-deprived actually have a better tolerance topain.
11. In spite of media reports, insomnia is not a common problem.
12. Insomniacs often sleep more than they realise.
13. Overuse of mobile phone apps can cause insomnia in some people.
参考答案：
1. memory 2. concentration 3.infants 4. proportion 5.epilepsy
6. immune system 7. energy
8. TRUE 9. NOT GIVEN 10.FALSE 11. FALSE 12.TRUE 13. NOT GIVEN
