时间:2015-03-04 07:24:41
“Its clear that the brain benefits from exercise,” says brain scientist William Greenough of the University of Illinois at UrbanaChampaign. His studies with rats have demonstrated two primary effects of activity: Vigorous physical exercise provides the brain with more fuel, and skillbased exercise increases the formation of connections in the brain, which, according to the proposals of some scientists, may make the brain better able to process information.
In one experiment, laboratory rats were separated into three groups. One group was exercised by running inside an automatic wheel, a second group improved their skills in a complicated obstacle course, and a third group was inactive.
“The animals that learned to go through the obstacle course exhibited a greater number of brain connections than the animals in the exercised or inactive groups,” Greenough said. “In contrast, the animals that exercised inside the automatic wheel possessed a greater density of blood vessels in the brain than did either of the other two groups of animals.”
Learning a new dance step may boost the brain in the same way that learning a language can, he says. And if the dance is a good physical exercise as well, the benefits multiply. Young brains may be especially able to boost brain power through exercise, suggested another of Greenoughs experiments that showed the most significant changes in the brain occurred among rats that had been exercised when very young. And while animals arent people, he says it is logical to make the inference that an effect found in rats may also apply to humans.
Human studies have focused primarily on older adults and suggest that regular exercise can improve the speed with which the brain processes information. Measurements made by Arthur Kramer at the University of Illinois demonstrated that inactive adults, aged 63 to 82, could hit buttons faster in response to a tone after they went through a 10week water exercise course. A corresponding control group that didnt exercise showed no improvement.
81. According to the passage what is not the advantage of physical exercises?()
A. do good to our mental health.B. strengthen our hearts and lungs.
C. strengthen our bones and muscles.D. help us lose weight.
82. Vigorous physical exercise can().
A. provide the brain with more fuel
B. increase the formation of connections in the brain [www.91exam.org]
C. make the brain better able to process information [www.91exam.org]
D. do nothing good to our brain
83. Which statement about the experiment of laboratory rats is correct?()
A. One group was exercised by running circles inside.
B. One group was exercised in a complicated obstacle course outside.
C. The animals that learned to go through the obstacle course exhibited a greater number of brain cells than the animals in the exercised or inactive groups.
D. The animals that exercised inside the automatic wheel possessed a greater density of blood vessels in the brain than did either of the other two groups of animals.
84. According to passage, what can not boost the brain?()
A. A new dance step.
B. A dance which is a good physical exercise as well.
C. Running on an automatic wheel.
D. Being inactive inside.
85. Which statement is correct according to the passage?()
A. The effect of exercises found in rats can not apply to people.
B. Changes in the brain occurred among young rats are more significant than those among adult rats.
C. Regular exercise can only improve the speed with which the older adults brain processes information.
D. The author encourages people do more skillbased exercise instead of vigorous physical exercise.