英语高级视听说下原文.doc

UNIT3 A PILL TO FORGET(CBS) If there were something you could take after experiencing a painful or traumatic event that would permanently weaken your memory of what had just happened, would you take it? As correspondent Lesley Stahl reports, its an idea that may not be so far off, and that has some critics alarmed, and some trauma victims filled with hope. I couldnt get my body to stop shaking. I was trembling, constantly trembling. Memories of it would just come back, reoccurring over and over and over, subway conductor Beatriz Arguedas recalls. Last Sept. 30, Beatriz was driving her normal route on the Red Line in Boston when one of her worst fears came to pass: Upon entering one of the busiest stations, a man jumped in front of my train, to commit suicide, she explains. Beatriz saw the man jump. We sort of made eye contact and then I felt the thud from him hitting the train and then the crackling sound underneath the train and, then, of course, my heart starts thumping, she recalls. She came into our emergency room afterwards, very upset. No physical injury. Entirely a psychological trauma, says Dr. Roger Pitman, a psychiatrist at Harvard Medical School who has studied and treated patients with post-traumatic stress disorder, or PTSD, for 25 years. Theyre caught up so much with this past event that its constantly in their mind, Pitman explains. Theyre living it over and over and over as if its happening again. And they just cant get involved in real life. When Beatriz arrived in the emergency room, Pitman enrolled her in an experimental study of a drug called propranolol, a medication commonly used for high blood pressure . and unofficially for stage fright. Pitman thought it might do something almost magical trick Beatrizs brain into making a weaker memory of the event she had just experienced. In the study, which is still under way, half the subjects get propranolol; half get a placebo. Asked whether he knows if Beatriz got the drug or the placebo, Dr. Pitman says he has no idea and neither does she, and that the research team wont know for another two years. If Pitman is right, the results could fundamentally change the way accident victims, rape victims, even soldiers are treated after they experience trauma. The story begins with some surprising discoveries about memory. It turns out our memories are sort of like Jello they take time to solidify in our brains. And while theyre setting, its possible to make them stronger or weaker. It all depends on the stress hormone adrenaline. The man who discovered this is James McGaugh, a professor of neurobiology at the University of California, Irvine. McGaugh studies memory in rats, and he invited Stahl to watch the making of a rat memory in this case how a rat whos never been in this tank of water before learns how to find a clear plastic platform just below the surface. Hell swim around randomly, McGaugh explains. The rat cannot see the platform, since his eyes are on the top of his head. The rat will swim around the edge for a long time, until eventually he ventures out and by chance bumps into the platform. The next day, hell find the platform a little bit faster. But another rat, who had learned where the platform was the day prior, and then received a shot of adrenaline immediately afterwards, today swam instantly to the platform. Adrenaline actually made this rats brain remember better, and McGaugh believes the same thing happens in people. Suppose I said to you, You know, Ive watched your programs a lot over the years, and although it pains me to have to tell you this, I think youre one of worst people Ive ever seen on now dont take it, dont take it personally, McGaugh says. So, my stress system would go into overdrive, no question, Stahl says. Even with my telling you that its not true, theres nothing to keep you from blushing, from feeling warm all over, McGaugh points out. Thats the adrenaline. And I dare say that youre gonna remember my having said that long after youve forgotten the other details of our discussion here. I guarantee it. McGaugh says thats why we remember important and emotional events in our lives more than regular day-to-day experiences. The next step in his research was to see what would happen when adrenaline was blocked; he started experimenting with propranolol. Propranolol sits on that nerve cell and blocks it, so that, think of this as being a key, and this is a lock, the hole in the lock is blocked because of propranolol sitting there. So adrenaline can be present, but it cant do its job, McGaugh explains. McGaugh showed Stahl a third rat that had learned where the platform was on the previous day and then received an injection of propranolol. The next day, the rat swam around the edge, as if he had forgotten there ever was a platform out there. Across the country at Harvard, Roger Pitman read McGaughs studies and a light bulb went on. When I read about this, I said, This has got to be how post-traumatic stress disorder works. Because think about what happens to a person. First of all, they have a horribly traumatic event, and they have intense fear and helplessness. So that intense fear and helplessness is gonna stimulate adrenaline, Pitman says. And then what do we find three months or six months or 20 years later? Excessively strong memories. Pitman figured he could block that cycle by giving trauma victims propranolol right away . before adrenaline could make the memories too strong. He started recruiting patients for a small pilot study. One of the first was Kathleen Logue, a paralegal who had been knocked down in the middle of a busy Boston street by a bicyclist. He just hit the whole left side of my body. And it seemed like forever that I was laying in the middle of State Street, downtown Boston, Logue remembers. She says she was terrified that she was just going to get run over. As part of the study, Logue took propranolol four times a day for 10 days. Like the others who got the drug, three months later she showed no physiological signs of PTSD, while several subjects who got a placebo did. Those results got Pitman funding for a larger study by the National Institutes of Health. But then the Presidents Council on Bioethics condemned the study in a report that said our memories make us who we are and that re-writing memories pharmacologically risks undermining our true identity. This is a quote. It risks making shameful acts seem less shameful or terrible acts less terrible than they really are, Stahl reads to Logue. A terrible act, she replies. Why should you have to live with it every day of your life? It doesnt erase the fact that it happened. It doesnt erase your memory of it. It makes it easier to remember and function. David Magnus, director of Stanford Universitys Center for Biomedical Ethics, says he worries that it wont be just trauma victims trying to dull painful memories. From the point of view of a pharmaceutical industry, theyre going to have every interest in having as many people as possible diagnosed with this condition and have it used as broadly as possible. Thats the reality of how drugs get introduced and utilized, Magnus argues. Hes concerned it will be used for trivial reasons. If I embarrass myself at a party Friday night and instead of feeling bad about it I could take a pill then Im going to avoid not have to avoid making a fool of myself at parties, Magnus says. So you think that that embarrassment and all of that is teaching us? Stahl asks. Absolutely, Magnus says. Our breakups, our relationships, as painful as they are, we learn from some of those painful experiences. They make us better people. But while the ethicists debate the issue, the science is moving forward. Researchers have shown in rat studies that propranolol can also blunt old memories. Pitman wondered: Could it work in humans? He teamed up with Canadian colleague Alain Brunet, who searched for people with long-standing PTSD, like Rita Magil. She had suffered for three years from nightmares after a life-threatening car accident. Another study subject is Louise ODonnell-Jasmin, who was raped by a doctor at the age of 12. He raped me on his desk, on a chair, and on the floor. It, for me, it was like I was dying inside, she remembers. The world had ended. ODonnell-Jasmin was haunted by the rape for more than 30 years. She never felt comfortable undressing in front of her husband and suffered from recurrent flashbacks and nightmares. The study was simple: Subjects came in and were asked to think about and write down every detail they could remember about their trauma; in Magils case, her car accident, reactivating the memory in her brain. She was then given propranolol. Rita says she suffered no side effects. A week later, electrodes measured her bodys stress response as she listened to a retelling of her trauma. Asked what happened, Magil says, No reaction. And she says she had no more nightmares. The patient who made the most dramatic recovery turned out to be ODonnell-Jasmin, but theres a catch, because she was in a control group and therefore wasnt supposed to improve at all. ODonnell-Jasmin was given propranolol, but unlike Magil, she took the drug while watching a pleasant movie, not after telling every detail about her rape. And yet, a week later, she noticed a change. I wake up. And I find myself undressing. And my husband is there. And I realize Im undressing, and Im not feeling as though I need to hide under the bed anymore, she explains. Asked if it is gone, ODonnell-Jasmin says, Yes. The link, what held the emotions to the memories, its like the umbilical cord has been cut. And there is no way I can access the emotions anymore. And furthermore, every day it gets better. Louise got a great result. But, scientifically, it confused things, Pitman says. He speculates that despite the pleasant movie, ODonnell-Jasmin may have been thinking about the rape when she took the propranolol, and thats why it worked. The only way were going to know is to study another 10 or a hundred patients like Louise and see how it pans out,” Pitman says. That this drug could actually alter and weaken old memories means were talking about a potentially revolutionary advance in treating post traumatic stress disorder. Are you at all concerned that since propranolol is already out there available for doctors to prescribe for heart conditions, for stage fright, that some soldier whos come back and is having terrible nightmares can go to his doctor and get it right now? Is that a concern for you, or not a concern? Stahl asks McGaugh. No. Not a concern for me. Not a concern, he replies. If it helps, why not. Let me tell you something that you told us before. Im quoting you. Its like they went in and altered my mind, Stahl tells Louise. ODonnell-Jasmin admits its very creepy. This study has taken away a part of me thats been in me for so long, and that I find very weird, she says. Its not normal to have gone through a rape and feel nothing. Or to have gone through something traumatic and feel as though it happened to somebody else, Stahl tells Pitman. Lets suppose you have a person who comes in after a physical assault and theyve had some bones broken, and theyre in intense pain. Should we deprive them of morphine because we might be taking away the full emotional experience? Who would ever argue that? Pitman replies. No, Stahl says. Why should psychiatry be different? I think that somehow behind this argument lurks the notion that mental disorders are not the same as physical disorders. That treating them or not is more of an optional thing, Pitman says. The studies are still in their early stages, so ODonnell-Jasmins apparent positive result isnt conclusive, though to her, its absolutely real. Asked if there is any sense that she has lost any of her identity, ODonnell-Jasmin says, I have regained my identity. What was broken when I was 12 was fixed. They have given me back myself. And now the U.S. military has taken note: Pitman recently heard from the Army that he will be receiving funding starting next summer to try the same propranolol experiment done with Magil and ODonnell-Jasmin o treat American soldiers returning from Afghanistan and IraqUnit 4 Brain ManAlmost 25 years ago, 60 Minutes introduced viewers to George Finn, whose talent was immortalized in the movie Rain Man. George has a condition known as savant syndrome, a mysterious disorder of the brain where someone has a spectacular skill, even genius, in a mind that is otherwise extremely limited.Morley Safer met another savant, Daniel Tammet, who is called Brain Man in Britain. But unlike most savants, he has no obvious mental disability, and most important to scientists, he can describe his own thought process. He may very well be a scientific Rosetta stone, a key to understanding the brain. _Back in 1983, George Finn, blessed or obsessed with calendar calculation, could give you the day if you gave him the date.What day of the week was August 13th, 1911? Safer quizzed Finn.A Sunday, Finn replied.What day of the week was May 20th, 1921? Safer asked.Friday, Finn answered.George Finn is a savant. In more politically incorrect times he would have been called an idiot savant - a mentally handicapped or autistic person whose brain somehow possesses an island of brilliance.Asked if he knew how he does it, Finn told Safer, I dont know, but its just that, thats fantastic I can do that.If this all seems familiar, there?s a reason: five years after the 60 Minutes broadcast, Dustin Hoffman immortalized savants like George in the movie Rain Man.Which brings us to that other savant we mentioned: Daniel Tammet. He is an Englishman, who is a 27-year-old math and memory wizard.I was born November 8th, 1931, Safer remarks.Uh-huh. Thats a prime number. 1931. And you were born on a Sunday. And this year, your birthday will be on a Wednesday. And youll be 75, Tammet tells Safer.It is estimated there are only 50 true savants living in the world today, and yet none are like Daniel. He is articulate, self-sufficient, blessed with all of the spectacular ability of a savant, but with very little of the disability. Take his math skill, for example.Asked to multiply 31 by 31 by 31 by 31, Tammet quickly - and accurately - responded with 923,521.And it?s not just calculating. His gift of memory is stunning. Briefly show him a long numerical sequence and he?ll recite it right back to you. And he can do it backwards, to boot.That feat is just a warm-up for Daniel Tammet. He first made headlines at Oxford, when he publicly recited the endless sequence of numbers embodied by the Greek letter Pi. Pi, the numbers we use to calculate the dimensions of a circle, are usually rounded off to 3.14. But its numbers actually go on to infinity.Daniel studied the sequence - a thousand numbers to a page.And I would sit and I would gorge on them. And I would just absorb hundreds and hundreds at a time, he tells Safer.It took him several weeks to prepare and then Daniel headed to Oxford, where with number crunchers checking every digit, he opened the floodgates of his extraordinary memory.Tammet says he was able to recite, in a proper order, 22,514 numbers. It took him over five hours and he did it without a single mistake.Scientists say a memory feat like this is truly extraordinary. Dr. V.S. Ramachandran and his team at the California Center for Brain Study tested Daniel extensively after his Pi achievement.What did he make of him?I was surprised at how articulate and intelligent he was, and was able to interact socially and introspect on his own-abilities, says Dr. Ramachandran.And while that introspection is extremely rare among savants, Daniel?s ability to describe how his mind works could be invaluable to scientists studying the brain, our least understood organ.Even how you and I do 17 minus nine is a big mystery. You know, how are these little wisps of jelly in your brain doing that computation? We dont know that, Dr. Ramachandran explains.It may seem to defy logic, but Ramachandran believes that a savant?s genius could actually result from brain injury. One possibility is that many other parts of the brain are functioning abnormally or sub-normally. And this allows the patient to allocate all his attentional resources to the one remaining part, he explains. And theres a lot of clinical evidence for this. Some patients have a stroke and suddenly, their artistic skills improve.That theory fits well with Daniel. At the age of four, he suffered a massive epileptic seizure. He believes that seizure contributed to his condition. Numbers were no longer simply numbers and he had developed a rare crossing of the senses known as synesthesia. I see numbers in my head as colors and shapes and textures. So when I see a long sequence, the sequence forms landscapes in my mind, Tammet explains. Every number up to 10,000, I can visualize in this way, has its own color, has its own shape, has its own texture.For example, when Daniel says he sees Pi, he does those instant computations, he is not calculating, but says the answer simply appears to him as a landscape of colorful shapes.The shapes arent static. Theyre full of color. Theyre full of texture. In a sense, theyre full of life, he says.Asked if they?re beautiful, Tammet says, Not all of