英語聽力文摘 吃藥要慎重！

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Drugs and Learning

Don: Yaël, when you experience something new, do you know what happens to your brain?

Yaël: Some of the neurons in your brain build new connections. My brain is rewired, as scientists often put it. Our brains are always changing, in response to new experiences or as a result of learning new information. That’s how we’re able to learn and remember new experiences and information.

D: You got it! But you know what happens to your brain when you experience new things after you done psychol similar drugs, such as amphetamine or cocaine?

Y: The same thing? Right?Or no?

D: The answer is, no! Evidence indicates that prior use of some drugs impairs the brain’s ability to forge new connections between neurons in response to new experiences. Scientists took a bunch of rats and gave some of them either amphetamine or cocaine for twenty days, while giving the others a saline solution for twenty days.

When the twenty days were up, half of the rats were moved from ordinary laboratory cages to fancy new cages equipped with all kinds of bridges, ramps, tunnels, and other toys. After three and half months the scientists examined all of the rats brains.

They discovered that the saline solution rats that were moved to the new cages had a greater number of neuronal connections than all the other rats, including the drugged rats in the new cages. These findings may aid in explaining some of the behavioral and cognitiveimpairments viewed in people who are addicted to drugs.

藥物與學(xué)習(xí)能力

Don: Yaël，你知道當(dāng)你碰到新的東西的時(shí)候，你的大腦會(huì)發(fā)生什么嗎?

Yaël: 大腦中的神經(jīng)元會(huì)建立起新的連接。就像科學(xué)家們經(jīng)常做的，這個(gè)時(shí)候的大腦在重新裝入信息。由于我們接觸到了新的東西或是獲得了新的信息，我們的大腦一直都在不停的變化——我們就是以這樣的方式來學(xué)習(xí)和記憶新的東西，新的信息。

D: 就是這樣的。但是你知道在服用了安非他命或可卡因這一類藥物這樣的情況下，接觸到新事物時(shí)你的大腦又會(huì)發(fā)生什么嗎?

Y: 沒什么不同的，吧?對(duì)嗎?

D: 答案當(dāng)然是“No”。有科學(xué)依據(jù)稱，在接觸新事物之前服用某些藥物會(huì)破壞大腦神經(jīng)元之間(因新事物的刺激)建立連接的能力?？茖W(xué)家們用大量的老鼠來做了試驗(yàn)。他們將老鼠分成兩組，給第一組老鼠喂食20天的安非他命或是可卡因，給第二組老鼠喂食20天的鹽水。

20天過后，他們將一半的老鼠從普通的實(shí)驗(yàn)籠子轉(zhuǎn)移到“超豪華”的新籠子里，里面有橋梁，有坡道，有隧道，還有其他的玩具。三個(gè)半月后，科學(xué)家們對(duì)老鼠的大腦進(jìn)行了仔細(xì)的研究。

他們發(fā)現(xiàn)，搬入新“家”的喂食鹽水的老鼠比其他的老鼠(包括搬入新籠子的喂食了藥物的老鼠在內(nèi))建立了更多的神經(jīng)元連接。這些研究發(fā)現(xiàn)可能有助于解釋為什么那些吸毒成癮的人會(huì)有一定的行為和認(rèn)知障礙。