Scientists have exactly discovered the set of...

Scientists have exactly discovered the set of brain cells involved in making risky decisions, and have been able to control them in rats using targeted light. By changing the activity of the cells they were able to change the behaviour of risk-taking rats to avoid risk, hinting the approach could in future be used to treat people with impulse (冲动) control problems.

Risk-taking is a key part of survival, knowing when to take a chance could pay off—such as moving to a new area to look for food when pickings are slim.

While all animals need an element of risk, the preference towards it varies between individuals. Researchers found this variation, which determines how risk-averse an individual is, is regulated by brain cells in a region of the brain called the nucleus accumbens. This cluster of neurons releases the neurotransmitter dopamine, which regulates the brain’s reward and pleasure centres.

Previous studies have shown that in patients with Parkinson’s disease, taking medication which blocks specific dopamine receptors (DR2) (受体) leads to increased gambling (赌博) behaviour and risk taking behaviour. In studies with rats, researchers were able to use a technique called optogenetics (光遗传学)—which uses light sensitive proteins to change the activity of cells—to modify cells with DR2 in the nucleus accumbens.

Rats were trained to choose one of two levers, offering them a choice between a “safe” or “risky” choice. The safe option resulted in a small, but consistent amount of a sugar water treat. But the risky choice consistently delivered smaller amounts of sugar water, with the occasional large pay off—essentially encouraging the animals to gamble for a bigger prize. Around two-thirds of the animals weren’t keen on risk, opting for the safe option, but the remaining third were risk-seekers. Brain scans of the animals showed that those with low levels of DR2 consistently went for the gamble.

But using pulses of light to stimulate (刺激) the DR2 cells and improve their activity could cause the risk-takers to play it safe and opt for the guaranteed but less rewarding option. Once the light-pulses stopped, the risk-takers returned to their gambling strategy.

In the risk-averse animals, stimulating the same cells had little to no effect.

Professor Karl Deisseroth, of Stanford University in California, said: “Humans and rats have similar brain structures involved.”And we found a drug known to increase risk preference in people had the same effect on the rats. So every indication is that these findings are relevant to humans. “Risky behavior has its moments where it’ s valuable. As a species, we wouldn’t have come as far as we have without it.”

1.The variation in people’s preference towards risks is directly regulated by ________.

A. nucleus accumbens　　　 B. light sensitive proteins

C. neurons　　　 　　　　　　 D. dopamine

2.From the experiment with rats, we can conclude that ________.

A. the lack of DR2 cells results in a safe option

B. the levels of DR2 have little to do with their choices

C. the high levels of DR2 can make animals avoid risks

D. the risky choice is a less rewarding option

3.The underlined words in Paragraph 7 most likely mean the animals that are ________.

A. willing to take big risks

B. reluctant to take risks

C. fond of gambling strategy

D. afraid of receiving stimulation

4.What can be inferred from what Professor Karl Deisseroth said?

A. Humans and rats differ in their preference for risk-taking.

B. Too much risk-taking can do more harm than good.

C. Risk-taking can be used to treat people with impulse control problems.

D. Risk-taking is a means of survival and brings higher returns to humans.

高三英语阅读理解中等难度题查看答案及解析

Scientists have exactly discovered the set of brain cells involved in making risky decisions, and have been able to control them in rats using targeted light. By changing the activity of the cells they were able to change the behaviour of risk-taking rats to avoid risk, hinting the approach could in future be used to treat people with impulse (冲动) control problems.

Risk-taking is a key part of survival, knowing when to take a chance could pay off—such as moving to a new area to look for food when pickings are slim.

While all animals need an element of risk, the preference towards it varies between individuals. Researchers found this variation, which determines how risk-averse an individual is, is regulated by brain cells in a region of the brain called the nucleus accumbens. This cluster of neurons releases the neurotransmitter dopamine, which regulates the brain’s reward and pleasure centres.

Previous studies have shown that in patients with Parkinson’s disease, taking medication which blocks specific dopamine receptors (DR2) (受体) leads to increased gambling (赌博) behaviour and risk taking behaviour. In studies with rats, researchers were able to use a technique called optogenetics (光遗传学)—which uses light sensitive proteins to change the activity of cells—to modify cells with DR2 in the nucleus accumbens.

Rats were trained to choose one of two levers, offering them a choice between a “safe” or “risky” choice. The safe option resulted in a small, but consistent amount of a sugar water treat. But the risky choice consistently delivered smaller amounts of sugar water, with the occasional large pay off—essentially encouraging the animals to gamble for a bigger prize. Around two-thirds of the animals weren’t keen on risk, opting for the safe option, but the remaining third were risk-seekers. Brain scans of the animals showed that those with low levels of DR2 consistently went for the gamble.

But using pulses of light to stimulate (刺激) the DR2 cells and improve their activity could cause the risk-takers to play it safe and opt for the guaranteed but less rewarding option. Once the light-pulses stopped, the risk-takers returned to their gambling strategy.

In the risk-averse animals, stimulating the same cells had little to no effect.

Professor Karl Deisseroth, of Stanford University in California, said: “Humans and rats have similar brain structures involved.”And we found a drug known to increase risk preference in people had the same effect on the rats. So every indication is that these findings are relevant to humans. “Risky behavior has its moments where it’ s valuable. As a species, we wouldn’t have come as far as we have without it.”

1.The variation in people’s preference towards risks is directly regulated by ________.

A. nucleus accumbens　　　 B. light sensitive proteins

C. neurons　　　 　　　　　　 D. dopamine

2.From the experiment with rats, we can conclude that ________.

A. the lack of DR2 cells results in a safe option

B. the levels of DR2 have little to do with their choices

C. the high levels of DR2 can make animals avoid risks

D. the risky choice is a less rewarding option

3.The underlined words in Paragraph 7 most likely mean the animals that are ________.

A. willing to take big risks

B. reluctant to take risks

C. fond of gambling strategy

D. afraid of receiving stimulation

4.What can be inferred from what Professor Karl Deisseroth said?

A. Humans and rats differ in their preference for risk-taking.

B. Too much risk-taking can do more harm than good.

C. Risk-taking can be used to treat people with impulse control problems.

D. Risk-taking is a means of survival and brings higher returns to humans.

高三英语阅读理解中等难度题查看答案及解析

(NEW YORK)---Scientists have discovered small signs of awareness in some vegetative(植物人的) brain injury patients and have even communicated with one of them---findings that are beneficial to how to assess and care for such people.

The new research suggests that standard tests may ignore patients who have some consciousness, and that someday some kind of communication may be possible.

In the strongest example, a 29-year-old patient was able to answer yes-or-no questions by picturing specific scenes the doctors asked him to imagine.

“We were stunned when this happened,” said one study author, Martin Monti of the Brain Sciences Unit in Cambridge. “I find it really amazing. This was a patient who was believed to be vegetative for five years.”

Ever since a research paper four years ago described obvious signs of awareness in a vegetative patient, families of patients have been demanding brain scans, said Dr. James Bernat, a spokesman for the American Academy for Neurology.

But experts said more study is needed before the specialized brain scans could be used in medical treatment. “It’s still a research tool,” Bernat said.

Experts also pointed out that only a few tested patients showed evidence of awareness. And they said it is not clear what degree of consciousness and mental abilities the signs imply.

They also noted that the positive signals appeared only in people with traumatic(外伤的) brain injury---not in patients whose brains had been lacking in oxygen, as can happen when the heart stops.

The new study used brain scanning called functional MRI, for 23 patients in a vegetative state and 31 that are minimally(极微地) conscious.

Patients are said to be in a vegetative state if they are tested and found unable to do such things as move on command or follow a moving object with their eyes. Minimally conscious patients show signs of awareness, but they are minimal and discontinuous.

1. What is the practical use of the research?

2.What does the underlined word “stunned” in Paragraph 4 probably mean?

3.One is considered vegetative if _______________.

4.The passage mainly deals with ________________.

高三英语阅读理解中等难度题查看答案及解析

1.　　 　 Scientists and experts have proved the uniqueness of finger-prints and discovered that no exactly similar pattern is passed on from parents to children, though nobody knows why this is the case.

The ridge （隆起） structure on a person's fingers does not change with growth and is not affected by surface injuries．Burns, cuts and other damage to the outer part of the skin will be replaced in time by new one, which bears a reproduction of the original pattern．2. 　 　 Some criminals make use of this fact to remove their own finger-prints but this is a dangerous and rare step to take.

Finger-prints can be made very easily with printer's ink．They can by recorded easily．3. 　 Because of the simplicity and economy of this system, finger-prints have often been used as a method of solving criminal case．A suspected man may deny a charge but this may be in vain．4. 　 　

When a suspect leaves finger-prints behind at the scene of a crime, they are difficult to detect with the naked eye.

5.　 　 Some of the marks found are incomplete but identification is possible if a print of a quarter of an inch square can be obtained.

A．Special techniques are used to "develop" them.

B．A fingerprint is an impression of the friction ridges of all part of the finger.

C．It is only when the inner skin is injured that the arrangement will be destroyed.

D．With special methods, identification can be achieved successfully within a short time.

E．A latent print is the chance reproduction of the friction ridges deposited on the surface of an item.

F．His finger-prints can prove who he is even if his appearance has been changed by age or accident.

G．Every human being has a unique arrangement of the skin on his fingers and this arrangement is unchangeable.

高三英语其他题中等难度题查看答案及解析

It has been discovered that after the age of sixteen, the number of our brain cells begins to decrease at a speed of several million a year. They simply die off. In certain types of activity, the human brain is at its highest point in the early twenties, when it has collected enough information to be able to use the vast number of cells freely in the most effective way. Pure mathematics is one of the fields in which this happens, and we know that Albert Einstein made all his world-shaking discoveries between the age of about 20 and 25, and spent the rest of his life tidying them up and arranging them.

But in certain other types of activity (of which being an author is perhaps one), experience is more important than sharpness of brain, and there one usually finds that a person reaches his or her peak much later in life.

Besides sharpness of brain and experience, here is another thing that is very important, and that is wisdom. One can have a very quick, inventive brain and plenty of experience, but if one uses these foolishly, one harms both oneself and others. Wisdom does not always come with age ——there are plenty of foolish middle-aged people about ——but the average person tends to learn wisdom as he gets older, usually by making painful of embarrassing mistakes. Leaning to be wise is basically learning what is not possible ； and what is possible but so difficult that it is not worth all the trouble one has to go through to get there. Mostly, it is learning about human nature ； how real people behave and react, as against how one would like them to behave and react. One can read and hear lot of idealistic stuff about how to make the world a better place, which would be found if it was based on an accurate observation of human nature, but which is basically a waste of time because it is not.

1.According to the writer, the great discoveries made by Albert Einstein were mainly a result in　　　 .

A.years of hard work B.sharpness of the brain

C.rich experience D.his deep understanding of the nature

2.Some people achieve success much later in life because .

A.their work often requires much experience

B.they do not have a chance to show their talents

C.they have to learn lessons from failures

D.they fail to realize earlier the importance of hard work

3.The importance of wisdom lies in the fact that .

A.it helps to avoid various mistakes

B.it contributes to one's creativity

C.it encourages one to go forward in face of difficulty

D.it provides the right direction of efforts

4.The writer came to believe that .

A.it is always a waste of time to make plans about the future

B.it is human nature to make attempts on what looks impossible

C.one should always challenge the impossible to push the society forward

D.one has to use wisdom in deciding what is the best thing to do

高三英语阅读理解中等难度题查看答案及解析

Stress in middle age can make your brain shrink and make your memory worse, scientists have discovered. The brain-reducing effects of stress, identified in people in their 40s free from dementia - a serious mental disorder caused by brain disease or injury, were found to be caused by cortisol(皮质醇). The high levels of the stress hormone may be an early warning “sign that someone may end up with dementia, the research suggests.

Stress also made people's thinking skills worse, which the Harvard Medical School study, published in the journal Neurology found. For the research, scientists led by Dr. Justin B. Echouffo-Tcheugui studied 2,231 people with an average of 49 and free of dementia. He said." Our research detected memory loss and brain shrinkage in middle-aged people before symptoms started to show. So it's important for people to find ways to reduce stress, such as getting enough sleep, taking part in moderate exercise, making relaxation techniques part of their daily lives or asking their doctor about their cortisol levels and taking a cortisol-reducing medication if needed. "He also added, "It's important for physicians to give professional advice to all people with high cortisol levels."

Researchers found lower scores on tests of memory and thinking in people with higher levels of cortisol than those with average levels. In addition, people with higher cortisol levels had a smaller brain volume, with those with high cortisol levels having brains that were 88.5 per cent of the total cranial(颅骨的) volume. This was compared to 88. 7 percent of the total cranial volume for people with normal levels of the hormone. No links were found between low levels of cortisol and brain size.

Cortisol helps the body respond to stress and when we are stressed, cortisol levels increase because that is our fight - or - flight(战或逃) response. It can also help reduce inflammation(发炎) and control blood sugar and blood pressure. High cortisol levels can be caused by stress, medical conditions or medications.

“Cortisol affects many different functions so it is important to fully investigate how high levels of the hormone may affect the brain," Dr Echouffo-Tcheugui said, “While other studies have examined cortisol and memory, we believe our large, community-based study is the first to explore, in middle-aged people, cortisol levels and brain volume, as well as memory and thinking skills. ”

1.What may Dr. Echouffo-Tcheugui suggest people do about stress-reducing?

A.Early to bed and early to rise. B.Strengthen the social network.

C.Eat food with more protein. D.Ride a bicycle around a lake.

2.Which statement about cortisol may the author agree to?

A.Higher cortisol levels are associated with larger brain volume.

B.The more stressed one feels, the higher his cortisol levels are.

C.Age and gender play a big role in the participants' brain volume.

D.People with high cortisol levels will suffer from low blood pressure.

3.What's the possible direction for future research according to Dr. Echouffo-Tcheugui?

A.How high cortisol levels affect human brains.

B.The link between cortisol levels and memory

C.The link between cortisol levels and brain size.

D.How cortisol affects peoples response.

4.Why does the author write this passage?

A.To suggest the efficient ways to reduce stress.

B.To prevent the features and functions of cortisol.

C.To explain how cortisol affects people s stress level.

D.To show stress can cause memory loss and brain shrinkage.

高三英语阅读理解中等难度题查看答案及解析

Scientists don’t know yet whether cell phones are bad for the brain.1.

In the experiment, the 47 participants may have looked a little strange. Each of them had two Samsung cell phones tied to his or her head—one on each ear.2.　 The phone on the right　 ear played a message for 50 minutes, but the participants couldn’t hear it because the sound was off. After 50 minutes with two phone attached to their heads, the participants were given PET scans. The PET scan is a way to take a three-dimensional picture of how the inside of the bodyworks.

The PET scan showed that the left side of each participant’s brain hadn’t changed from the way it was before the experiment.3. These right-side brain　 cells were　 using　 almost　 as　 much glucose as the brain uses when a person is talking. This suggests that brain cells there were active even without the person hearing or talking anything. This activity, the scientists say, was probably touched off by radiation from the phone.

4. They release different amounts of radiation depending on whether a person　 is　 talking or listening, the type of phone, the number of people using phones nearby, and the distance to the nearest cell phone tower. All of these changes make it difficult to collect evidence about any health risks of cell phones, since exposure to radiation can vary.

So for those who don’t want to wait to find out for sure whether cell phones are bad for the brain, there are ways to talk more safely.5.

A.The phone on the left ear was off.

B.So an experiment was done to attempt to find it out.

C.People should avoid having a long conversation by using cell phones.

D.Cell phones do not always give out the same amount of energy.

E.You can have short conversations, use a speakerphone to keep the phone away from your head.

F.The right side of the brain, however, had used more glucose, which provided fuel to brain cells.

G.From the PET scan the differences between the two sides of the brain were observed.

高三英语七选五中等难度题查看答案及解析

Scientists have long wondered　　parts of the brain are involved in musical tasks.

A. that            B. which            C. whose            D. where

高三英语单项填空中等难度题查看答案及解析

SCIENTISTS have discovered that living to the age of 100 may have nothing to do with the lifestyle you lead and everything to do with the type of genes (基因) you have.

For the lucky carriers of “Methuselah” genes, worries over smoking, eating unhealthily and not getting enough exercise may not be as necessary as to those of us without the special gene pattern .

The “Methuselah” genes could give extra protection against the diseases of old age such as cancer and heart disease. They could also protect people against the effects of the unhealthy lifestyles that we believe will lead us to an early death, scientists say. However, the genes are very rare.

The genes include ADIPOQ, which is found in about 10 percent of young people but in nearly 30 percent of people living past 100. They also include the CETP and the ApoC3 genes, which are found in 10 percent of young people, but in about 20 percent of people over 100 years old.

Some of those genes were discovered by a research group at the Albert Einstein College of Medicine in New York, led by Professor Nir Barzilai. The team studied the genes of over 500 people over 100 years old, and their children.

The studies show that tiny mutations (变异) in the make-up of some genes can greatly increase a person’s lifespan. Barzilai told a Royal Society conference that the discovery of such genes gave scientists clear targets for developing drugs that could prevent age-related diseases, allow people to live longer and stay healthy.

David Gems, a researcher at University College London, believes that drugs to slow ageing will become widespread.

“If we know which genes control longevity (长寿) then we can … target them with drugs. That makes it possible to slow down ageing,” he told The Times.

“Much of the pain and suffering in the world are caused by ageing. If we can find a way to reduce that, then we are obliged to take it.”

1. According to the article, which of the following is the most important if a person is to live to the age of 100?

A. Eating healthy food every day.

B. Having the right types of genes.

C. Having a healthy lifestyle.

D. Taking drugs that prevent ageing.

2.According to the article, the ApoC3 gene is found in ______ of people over 100 years old.

A. 10%           B. 20%          C. 30%       D. 50%

3.Which of the following statements is TRUE of the research led by Professor Nir Barzilai?

A. The team studied the genes of over 100 people over 100 years of age.

B. The researchers found that mutations in certain genes lead to longer life.

C. The researchers found ways to develop drugs that could cure age-related diseases.

D. The study suggested that most people have genes that could lengthen their lives.

4. According to David Gems, ______.

A. drugs to slow ageing will be very expensive

B. modern science will be able to find more longevity genes

C. it is the duty of medical scientists to fight the problems of ageing

D. scientists can make new genes that will allow longer life

高三英语阅读理解中等难度题查看答案及解析

Scientists have discovered that living to the age of 100 may have nothing to do with the lifestyle you lead and everything to do with the type of genes you have.

For the lucky carriers of “Methuselah” genes， worries over smoking， eating unhealthily and not getting enough exercise may not be as necessary as to those of us without the special gene pattern.   The “Methuselah” genes could give extra protection against the diseases of old age such as cancer and heart disease. They could also protect people against the effects of the unhealthy lifestyles that we believe will lead us to an early death， scientists say. However， the genes are very rare.

The genes include ADIPOQ， which is found in about 10 percent of young people but in nearly 30 percent of people living past 100. They also include the CETP and the ApoC3 genes， which are found in 10 percent of young people， but in about 20 percent of people over 100 years old.

Some of those genes were discovered by a research group at the Albert Einstein College of Medicine in New York， led by Professor Nir Barzilai. The team studied the genes of over 500 people over 100 years old， and their children.

The studies show that tiny mutations (变异) in the make-up of some genes can greatly increase a person’s lifespan. Barzilai told a Royal Society conference that the discovery of such genes gave scientists clear targets for developing drugs that could prevent age-related diseases， allow people to live longer and stay healthy.

David Gems， a researcher at University College London， believes that drugs to slow ageing will become widespread.

“If we know which genes control longevity (长寿) then we can... target them with drugs. That makes it possible to slow down ageing，” he told The Times.

“Much of the pain and suffering in the world are caused by ageing. If we can find a way to reduce that， then we are obliged to take it.”

1.Which genes could give extra protection against the diseases of old age？ (No more than 3 words) (2 marks)

__________________________________________________________________________　

2. Whom did Barzilai’s team study？ (No more than 10 words) (2 marks)

__________________________________________________________________________

3. What can greatly increase a person’s lifespan？ (No more than 10 words) (3 marks)

__________________________________________________________________________

4.What can scientists do if they are aware which genes control longevity？(No more than 6 words) (3 marks)

__________________________________________________________________________.　

高三英语其他题中等难度题查看答案及解析