【答案解析】Just to liven things up a bit | tying a string around | with the string on it | on sticky notes | focus on a specific kind of | test their theory | exploring the areas | memory loop or circle | sets off | which in turn | suffered through | relive | less upsetting | in other words | cutting-edge research paper | or retrieving | allow for two critical main factors | exposed volunteers to | being scanned with | blood flow in regions of the brain | injured people and violence | asked to rate | brought back associated details | made an impact on | as well as | were retrieved | make such conclusions | responsible for computing | the main memory-processing center | trigger retrieval and vice versa | which works like a circle | suffer from trauma | get therapy to help [听力原文]

Professor: Okay class. Just to liven things up a bit, we"re going to talk about something everyone has—a memory. Who here can give me some tips on how we remember things?
Student A: I remember things by tying a string around my finger. That way when I look at my finger with the string on it, I try to think back to why it"s there.
Student B: I tend to write things down on sticky notes and leave them on my desk where I regularly sit.
Student C: Come on guys, get into the 21st century! I enter notes on my Palm Pilot or mobile phone.
Professor: Well, all of these suggestions are good, but what if I told you that emotion can help you remember? Today we"re going to focus on a specific kind of memory and that is emotional memory. Some researchers feel that emotion can help us remember. In order for researchers to test their theory that positive and negative emotions can trigger memories, they began by exploring the areas in the brain involved in remembering an emotional memory. The study took over a year and they found some evidence of a memory loop or circle. The information starts at the brain"s emotional center, where it sets off the memory center, which in turn, boosts the activity in the emotional center, which results in an increase in memory.
Student A: So how can someone who has suffered through emotional trauma recover?
Professor: Researchers have concluded that people need to relive these memories and reshape their perspective of the trauma to make it less upsetting.
Student B: So, in other words, the person needs to keep remembering their horrible memories and change them into memories they can deal with.
Professor: Exactly. A cutting-edge research paper published in early 2005 studied the recall of emotional memories over a long period of time. Other research and papers mainly dealt with short time intervals such as a few minutes of encoding the information and then remembering or retrieving it. These short intervals did not allow for two critical main factors: consolidation, or establishing memories, and true recollection.
Student C: So how did the researchers test their theories?
Professor: The recent study exposed volunteers to images that were pleasant, unpleasant and neutral. At the same time, their brains were being scanned with functional magnetic resonance imaging or MRI.
Student A: Is this a common technique and is it dangerous?
Professor: Fear not, this technique is used all the time and the magnetic fields and radio waves used to show blood flow in regions of the brain, especially increased blood flow to show higher brain activity, are not dangerous at all.
Student B: What kind of images were the people shown?
Professor: They were shown pleasant images such as romantic scenes and sports. The unpleasant images involved injured people and violence. Finally, the neutral pictures showed buildings or other emotionally non-involving scenes.
Student C: How did the researchers know what the people thought of these images?
Professor: Well, they were asked to rate the emotional aspects of the images they saw. After one year, the same people were asked to come back and the researchers showed them the same images they had already seen, plus some new pleasant, unpleasant and neutral images while their brains were being scanned. The researchers asked the people to point out which images they had seen before and whether the memory also brought back associated details.
Student A: I guess the details indicated how well the people remembered the pictures.
Professor: Yes, if a picture made an impact on the people, they likely remembered the image. The interesting point of the test was that people did not remember the neutral pictures as well as the pleasant and unpleasant pictures. Therefore, emotional pictures were retrieved, but not the non-emotional ones.
Student C: Again, professor, I don"t understand how the researchers can make such conclusions.
Professor: There is an almond shaped area in your brain called the amygdala. This area of the brain is responsible for computing emotional significance of events. After the people were shown the emotional images, the amygdala increased. The researchers could see this through the brain scans. Another area of the brain affected by emotional memories is the hippocampus, the main memory-processing center. Both of these areas activate the other when we recall an emotional memory and this is exactly what happened to the people when they were shown emotional pictures. In other words, emotion can trigger retrieval and vice versa just as the amygdala and hippocampus can trigger each other.
Student A: So, emotion increases recollection and at the same time your recollection helps you remember the emotional response, which works like a circle.
Student B: Professor, this study is fantastic because it will really help people who suffer from trauma. Now they can get therapy to help not only with the trauma they keep remembering, but with the emotions they have as well.
Professor: Exactly.