听力文摘：我的大脑是静止的还是不断变化的?

Is My Brain Static Or Constantly Changing?

我的大脑是静止的还是不断变化的？

Scientists used to think that for all its complexity¹, the brain was pretty static. Once the brain matured, it essentially² stopped growing and changing. And when neurons, or brain cells, were lost or damaged, they were gone for good.

科学家们过去常常认为，大脑因为其复杂性而呈现出静止状态。一旦成熟，大脑基本上就会停止生长和变化。当神经元或大脑细胞丢失或损坏时，大脑就会坏死掉。

But recent discoveries have caused neuroscientists to change their tune³. The human brain is anything but static—in fact, it's constantly growing and changing as it adapts to new information and circumstances.

但是最近的发现让神经学家改变了看法。人类的大脑绝不是静止的——事实上，它是随着对新信息和新环境的适应不断生长和变化的。

For example, scientists now know that there's a mechanism⁴ in the hippocampus a brain part involved with memory, among other things that gives birth to new brain cells. Scientists don't know exactly why the brain makes new cells or what the cells do. They may have something to do with forming memories, or be used to replace dead or damaged cells.

举个例子来说，现在科学家们知道大脑内存在一种叫做海马体的记忆机制，可以产成新的大脑细胞。但是，科学家们不能确切地知道大脑为什么能生成新细胞，而这些细胞又能做什么。它们可能和形成记忆有关，或者被用于代替老去或损坏的细胞。

In any case, in a recent experiment, scientists working with mice shut down their brains'ability to make new cells. At first, the researchers observed that the mice had reduced functioning in cellular⁵ mechanisms⁶ in the brain important for memory formation.

不管怎样，在最近的一次实验中，科学家们用老鼠进行实验，他们消除了这些老鼠们大脑生成新细胞的能力。起初，研究人员观测到，老鼠大脑中对记忆生成非常重要的细胞机制的功能降低了。

But after about six weeks, they noticed that the mice's brains had begun to compensate⁷ by making existing neurons more active. Relatively⁸ newborn neurons created before the researchers shut down the neuron birthing process reacted by living longer than they normally would—almost as though they knew that replacements⁹ would not be forthcoming and so they had to work overtime¹⁰ to help the brain get back on course.

但是大约六周之后他们又发现，老鼠的大脑通过使现有的神经元变得更加活跃从而弥补之前的损失。相对地，在研究人员阻止神经元生成之前生成的神经元比一般生成的存活更长——就好像它们知道自己不会被很快代替，所以它们必须延时工作来帮助大脑回到正轨上。

This research is of the most basic, foundational kind. But knowing more about how the brain responds to changes could eventually have profound implications for how doctors understand and treat Alzheimer's, dementia, and other brain illnesses.

这项研究是最为基础的研究。但是，对大脑是如何变化的了解越多，就会对医生了解与治疗老年痴呆症、痴呆和其它大脑疾病产生更为深远的意义。

1 complexity   

n.复杂(性)，复杂的事物

参考例句：

• Only now did he understand the full complexity of the problem.直到现在他才明白这一问题的全部复杂性。
• The complexity of the road map puzzled me.错综复杂的公路图把我搞糊涂了。

2 essentially   

adv.本质上，实质上，基本上

参考例句：

• Really great men are essentially modest.真正的伟人大都很谦虚。
• She is an essentially selfish person.她本质上是个自私自利的人。

3 tune   

n.调子；和谐，协调；v.调音，调节，调整

参考例句：

• He'd written a tune,and played it to us on the piano.他写了一段曲子，并在钢琴上弹给我们听。
• The boy beat out a tune on a tin can.那男孩在易拉罐上敲出一首曲子。

4 mechanism   

n.机械装置；机构，结构

参考例句：

• The bones and muscles are parts of the mechanism of the body.骨骼和肌肉是人体的组成部件。
• The mechanism of the machine is very complicated.这台机器的结构是非常复杂的。

5 cellular   

adj.移动的；细胞的，由细胞组成的

参考例句：

• She has a cellular telephone in her car.她的汽车里有一部无线通讯电话机。
• Many people use cellular materials as sensitive elements in hygrometers.很多人用蜂窝状的材料作为测量温度的传感元件。

6 mechanisms   

n.机械( mechanism的名词复数 )；机械装置；[生物学] 机制；机械作用

参考例句：

• The research will provide direct insight into molecular mechanisms. 这项研究将使人能够直接地了解分子的机理。 来自《简明英汉词典》
• He explained how the two mechanisms worked. 他解释这两台机械装置是如何工作的。 来自《简明英汉词典》

7 compensate   

vt.补偿，赔偿；酬报 vi.弥补；补偿；抵消

参考例句：

• She used her good looks to compensate her lack of intelligence. 她利用她漂亮的外表来弥补智力的不足。
• Nothing can compensate for the loss of one's health. 一个人失去了键康是不可弥补的。

8 relatively   

adv.比较...地，相对地

参考例句：

• The rabbit is a relatively recent introduction in Australia.兔子是相对较新引入澳大利亚的物种。
• The operation was relatively painless.手术相对来说不痛。

9 replacements   

n.代替( replacement的名词复数 )；替换的人[物]；替代品；归还

参考例句：

• They infiltrated behind the lines so as to annoy the emery replacements. 他们渗透敌后以便骚扰敌军的调度。 来自辞典例句
• For oil replacements, cheap suddenly looks less of a problem. 对于石油的替代品来说，价格变得无足轻重了。 来自互联网

10 overtime   

adj.超时的，加班的；adv.加班地

参考例句：

• They are working overtime to finish the work.为了完成任务他们正在加班加点地工作。
• He was paid for the overtime he worked.他领到了加班费。