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.
Shop with Your Doc is part of a broader and still growing movement in US medicine to shift the focus away from simply treating disease toward caring for the whole person. It is meant to help people make educated, healthy choices one grocery cart at a time. Across the country, hospitals are setting up food banks and medical schools are putting cooking classes on the curriculum. Nonprofits are connecting medical centers with community resources to ensure that low-income Americans have access to fresh fruits and vegetables.
For centuries, Western medicine’s mission was to cure disease. But over the past generation, two generation, two significant trends are of concern to the medical community, says Timothy Harlan, executive director of Goldring Center for Culinary Medicine at Tulane University in New Orleans. Healthcare costs began to soar (激增), and relatively inexpensive, poor-quality food became more common. “There’s a very straightforward link between people improving their diets and improving the condition that they have,” Dr. Harlan says.
The connection drove the medical and nonprofit communities to rethink their approach to health. What emerged was the concept of the “social determinants of health”— the notion of taking into account the biological, physical, and socioeconomic circumstances surrounding a patient. A healthy person isn’t just someone who is free from disease, the theory goes; he or she also enjoys “a state of complete mental, physical and social well-being.”
The question the medical community now faces is how to get patients — especially low-income families — to recognize these determinants and make it possible for them to eat and live healthier. In Boston, medical experts responded by creating an on-site pantry (食品室) at Boston Medical Center. Since its founding in 2002, the pantry has evolved into a kind of nutrition center where primary care providers at BMC send patients for food. Today the pantry, which gets 95 percent of its stock from the Greater Boston Food bank, hosts free cooking classes and serves about 7,000 people a month. The Greater Boston Food Bank has also launched its own initiatives, striking partnerships with four community health centers across the state to offer free mobile produce markets. The organization also helped develop toolkits (软件包) that map local pantries. markets that accept government food vouchers, and other resources.
At Tulane in New Orleans, Harlan is leading the development of a curriculum that combines medicine with the art of food preparation. His philosophy: Doctors who know their way around a kitchen are better at helping their patients. And empowering patients to take charge of their own diets is one way to help them deal with the incredible costs of health care, Harlan says. The curriculum has since been adopted at 35 medical schools around the United States. Chipping away at bad habits is a good place to start getting patients to think about the choices they make for themselves and their families, say Dr Maureen Villasenor, the Orange County pediatrician (儿科医生).
1.The aim of Shop with Your Doc is to________.
A.help patients relax before an operation
B.assist patients in finding food fit for them
C.control people’s food consumption in supermarkets
D.persuade low-income families to take more fruits and vegetables
2.Paragraphs 2 and 3 mainly talk about_________.
A.the role Western medicine has been playing
B.how a new concept of health came into being
C.medical communities’ worries about food safety
D.why low-income families are less reliable on healthcare
3.What do we know about the Greater Boston Food Bank?
A.Its cooking classes are free of charge.
B.It was founded at the beginning of the 21st century.
C.It helps people locate pantries and markets.
D.It treats many a patient from BMC.
Brecon Beacons YAC has an amazing opportunity for budding(崭露头角的) archaeologists of all ages, in Sunderland in Tyne and Wear. Thanks to funding from the Heritage Lottery Fund, professional archaeologists from Wardell Armstrong will be investigating an archaeological mystery and they need your help.
Romans?
“The site is a bit of a mystery”, Frank Giecco from Wardell Armstrong said. “There is a very nice cropmark recorded on the site that has got lots of people very excited. Geophysicists failed to find anything relating to the cropmark. There is anecdotal evidence of Roman material being found, but nothing is officially recorded. We hope to finally answer the question of what is in this field, during the two weeks on site. Is there evidence of any Roman occupation on the site? Can you help us find out?”
Get involved
This is an opportunity for both adults and children to take part in field walking and trial trenching (small hand-dug test pits for children). No experience is necessary, training will be provided by the professional archaeologists from Wardell Armstrong, and all equipment will be provided. Volunteers can attend for as few or as many days as they wish, but they do need to book a place.
For more information, and to book your place, please contact Norman Kirtlan at sunderlandforgottenstones@gmail.com.
1.If you intend to take part in the activity, you ________.
A. will be charged for using equipment
B. will be coached by experts in the field
C. should have worked with archaeologists before
D. should spare two weeks to stay at the site
2.What’s the main purpose of the passage?
A. To seek funding for archaeological research.
B. To appeal for help in proving findings based on anecdotal evidence.
C. To find volunteers to help solve an archaeological mystery.
D. To organize volunteers to help sort our data on the Roman occupation.
请认真阅读下面短文, 从短文后各题所给的A、B、C、D四个选项中, 选出最佳选项, 并在答题纸上将该项涂黑。
How many licks (舔) does it take to get to the center of a Tootsie Pop (棒棒糖)?
The first time I heard this in the Tootsie Pop commercial, I was five years old. I immediately started_____and counting. After about two hundred licks or so, I stopped. The_____of the chewy center had proven to be too great, and I______my way through the hard shell (外壳) to the very center. Besides, I_____knew how many licks it took to get to the center—three. That’s how many licks it took the owl (猫头鹰) in the commercial to get to the center, so that, to me, was the_____answer.
In high school, I held to the Tootsie Pop_____To me, the answer was still always three licks.
In my freshman year, I joined the Model United Nations_____in my school. The Chair position had______the center of the Tootsie Pop and my_____had become various other students. The first so-called “owl” was Eric who had luckily_____the prestigious (声望高的) Chair position. So, I decided,_____Eric reached the center in only one lick, that’s how many licks it should take me. I went to the tryouts with a view to obtaining the position but______
At the end of my sophomore (高二) year, a new owl named Iris had_____achieved the chair position after trying twice. I began working hard again. But then again, I did not make a_____of it.
Now, slightly frustrated after_____two owls, I found a new owl, Evan. It had taken him three licks to get to the “center”. Three was all I could_____It was widely known that senior year was the_____year to become Chair. I thought about_____the program, but on second thoughts, I decided to continue.
Eleven years later, I visited the official Tootsie Pop website to find the real answer to the question that had_____me my entire high school life. I finally understood. However many licks it takes to get to the center of the Tootsie Pop depends on however many licks I_____to take—not how many the other owls take.
1.A.dreaming B.admiring C.licking D.chewing
2.A.temptation B.appearance C.power D.discovery
3.A.fought B.followed C.made D.bit
4.A.seldom B.never C.already D.nearly
5.A.brief B.right C.random D.temporary
6.A.commercial B.plan C.philosophy D.custom
7.A.program B.conference C.title D.activity
8.A.become B.changed C.determined D.explored
9.A.shell B.hope C.owl D.companion
10.A.noticed B.shifted C.improved D.landed
11.A.unless B.if C.before D.until
12.A.failed B.quitted C.survived D.struggled
13.A.yet B.even C.still D.also
14.A.promise B.success C.point D.joke
15.A.interacting with B.frightening away C.going through D.dealing with
16.A.afford B.hold C.admit D.expect
17.A.middle B.gap C.last D.initial
18.A.winning B.criticizing C.quitting D.arranging
19.A.motivated B.troubled C.attracted D.instructed
20.A.learn B.agree C.refuse D.choose
—How come Tom picked a quarrel with his wife?
—________? We also have the occasional argument.
A. What’s on B. How’s that
C. Who doesn’t D. Why not
Learning from ________ mistakes can help us keep conscious and avoid repeating them in the days to come.
A. previous B. curious C. obvious D. ridiculous
