英国新闻听力 看大脑如何消除记忆（在线收听）

Remembering makes us forget, at least according to a group of neuroscientists here in Britain who watched the volunteers remember one memory which in turn caused them to forget another. To explain the process, I spoke to the lead researcher from Birmingham University.

In the experiments we were interested in how the brain creates forgetting. And the challenge was it’s been quite hard to study forgetting cuz you can’t really tell. So what you need to find is something like a neuro fingerprint in the brain that tells us what exactly a subject or participant is remembering at a given moment. So we developed a method that actually allowed us to track individual memories in the brain. Sowe could directly watch the brain while it forgets. And that was quite exciting for us.

And you use pictures of Marilyn Monroe and Albert Einstein.

Yes, we do.

And why?

So we used these images which are all like famous people’s faces or well-known places around the world oreveryday objects, because they are quite well-known to our subjects already. So they are easier to remember in the first place. But also and probably more importantly we found that these pictures elicit quite a distinct signature in the brain like individual part of the brain. So we can actually tell just based on a participant’s brain activity.

And when you looked at those signatures, what did it tell you?

So it told us when there were words that triggered a memory of two pictures at the same time, the more often we asked participants to only remember one of these pictures, the more we saw the brain picture of thator the brain pattern representing that picture coming up in the brain, but also the more the competing or irrelevant pictures were suppressed by the brain. And that suppression ultimately led people to forget those memories at a later point. So the basic phenomenon which always surprises people that namely that remembering causes forgetting has been known for quite a while. So it’s been published in the nineties. But the new thing about our study is really that we can actually watch the mechanism behind it. So we can watch the brain while it’s suppresses memories that it doesn’t need any more.

记忆会让我们忘记，至少这事英国一些神经系统科学家的观点。他们观察到实验志愿者在回忆一件事的时候会忘掉另外一件。为了解释清楚这个过程，我采访了来自伯明翰大学的研究带头人。

在这些实验中，我们感兴趣的是大脑怎么进行遗忘。遇到的挑战是，研究遗忘非常困难，因为这真的不容易判断。所以需要在大脑中找到一个类似神经指纹的东西，来告诉我们实验对象或参与者在特定时刻想起了什么。因此，我们设计了一种方法来追踪人们大脑中的记忆。我们可以直接观察到大脑进行遗忘的过程。这令我们很兴奋。

你们还用了玛丽莲·梦露和爱因斯坦的照片。

是啊。

为什么呢？

我们用的照片都是些名人头像、世界名胜或者日常用品，因为我们的实验对象已经非常熟悉这些东西，更容易在第一时间记起来。但同时，可能更加重要的一点是，我们发现这些照片能够刺激大脑的特定部分发出明显的信号。所以，我们只需通过一个参与者的大脑活动得出判断。

那么这些信号给你们传递了怎样的信息？

这些信号告诉我们，当一些言语让参与者同时想到两幅图片时，我们越提醒参与者只记住其中的一幅，就越容易看到代表这幅图的大脑区域，而其他参与竞争或不相关的图片则受到大脑的抑制。这种抑制最终使人们逐渐淡忘那些记忆。记忆会产生忘记，这个基本现象经常令人吃惊，但很久以前人们就已经被发现了这种现象，并于90年代发表了相关研究。而我们研究的新意在于能够真切地观察到这种现象背后的机制。我们可以观察到大脑抑制它不需要要的记忆的过程。