阅读理解。
Sleeping in anything other than a completely dark room could cause depression (抑郁), according to a
new study of hamsters.
Tracy Bedrosian, a researcher at Ohio State University, US, presented the research on November 17 at
the annual meeting of the American Society for Neuroscience (神经系统科学) in San Diego.
Researchers believe that even having a dim (暗淡的) light on-such as a night light often used in a child's
room or the glow (发光) of a TV screen, changes the chemical balance of the brain.
While more work is needed to find out if the results are relevant to human beings, the findings might
explain why night-shift (夜班的) workers are at higher risk of depression than others, the researchers said.?
Over the last century, nighttime lights have become common, but it's not clear whether sleeping with one
has an effect on the brain.
As part of the investigation, Tracy Bedrosian, a researcher at Ohio State University, and her team, placed
hamsters in two environments. In one, hamsters experienced 16 hours of daylight and eight hours of complete
darkness each day. In the other, the animals experienced 16 hours of daylight, but at nighttime, a dim light was
kept on.
After eight weeks, the researchers tested the hamsters for behaviors that would suggest they were
depressed. For example, they looked to see whether the hamsters still practiced activities they usually enjoyed,
such as drinking sugar water.
In people, loss of enjoyment is known as a symptom of depression.
Hamsters in both groups were given a choice between drinking tap (水龙头) water or sugar water. The
hamsters that slept with lights on at night drank similar amounts of tap and sugar water - they'd lost their
preference (偏好) for the sweet water.
"That suggests to us that they are not getting the same pleasure from drinking their sugar water, and that
may be a depression-like response," Bedrosian said.
Researchers found these changes in behavior were caused by chemical changes in a part of brain called
the hippocampus (海马状突起).
Previous studies on humans have found the hippocampus to be involved in depression. A patient with major
depression has a smaller hippocampus, Bedrosian said.
If the same mechanism (机制) exists in people, then they "might want to try to avoid falling asleep with
their TVs on all night," Bedrosian said.
1. What may cause depression according to the article? [ ]
A. To sleep in the dark.
B. To sleep with the light on.
C. To sleep in a new environment.
D. To sleep after drinking sugar water.
2. What did Tracy Bedrosian and her team find in the research? [ ]
A. Loss of enjoyment is a symptom of depression.
B. Sleeping with the light on affects the human brain.
C. Two groups of hamsters drank similar amounts of sugar water.
D. Hamsters no longer enjoyed drinking sugar water after they had slept with the light on.
3. Which of the following statements is TRUE according to the article?[ ]
A. TV noise may affect quality of sleep.
B. A depressed patient has a larger hippocampus.
C. People who stay up late at night are more likely to be depressed.
D. The hamsters' behavioral changes were caused by chemical changes in the brain.
4. If the research turns out to be useful for understanding of human depression, it would be advisable _____. [ ]
A. to sleep with a night light
B. not to watch TV at night
C. to sleep in total darkness
D. to put an end to night shifts