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This is Scientific American's 60-Second Science. I'm Christopher Intagliata. Got a minute?

Doctors prescribe Ritalin to hyperactive kids to calm them down and increase their attention span. And college kids have taken to using Ritalin to concentrate when they hit the books. But it hasn't been clear how the drug boosts focus. Now a paper in the journal Biological Psychiatry¹ suggests how it might work. Neuronscientists dosed rats with Ritalin and had them perform the kind of working memory task ADHD patients have trouble with. At the same time,they measured neural² activity with tiny-electrodes implanted in the rats' brains.At low doses Ritalin primarily affected³ the prefrontal cortex,jacking up its sensitivity to signals coming in from the hippocampus.And here is how the drugs seemed to help with attention,it strengthened choruses of neurons firing together and put a damper on scattered⁴ uncoordinated activity. But at high doses the profrontal cortex tuned⁵ out and Ritalin's effects were similar to those of other stimulants⁶.The rats lost their cognitive⁷ edge and they became hyperactive,sniffing and licking repetitively.So Ritalin shows you can indeed have too much of a good thing to the point of distraction⁸.

Thanks for the minute for Scientific American's 60-Second Science. I am Christopher Intagliata.

WORDS AND EXPRESSIONS:

Hippocampus: The hippocampus is a part of the forebrain, located in the medial temporal lobe⁹.

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1 psychiatry
n.精神病学，精神病疗法
参考例句：
The study appeared in the Amercian science Journal of Psychiatry.这个研究发表在美国精神病学的杂志上。 A physician is someone who specializes in psychiatry.精神病专家是专门从事精神病治疗的人。

2 neural
adj.神经的，神经系统的
参考例句：
The neural network can preferably solve the non- linear problem.利用神经网络建模可以较好地解决非线性问题。 The information transmission in neural system depends on neurotransmitters.信息传递的神经途径有赖于神经递质。

3 affected
adj.不自然的，假装的
参考例句：
She showed an affected interest in our subject.她假装对我们的课题感到兴趣。 His manners are affected.他的态度不自然。

4 scattered
adj.分散的，稀疏的；散步的；疏疏落落的
参考例句：
Gathering up his scattered papers,he pushed them into his case.他把散乱的文件收拾起来，塞进文件夹里。

5 tuned
adj.调谐的，已调谐的v.调音( tune的过去式和过去分词 )；调整；（给收音机、电视等）调谐；使协调
参考例句：
The resort is tuned in to the tastes of young and old alike. 这个度假胜地适合各种口味，老少皆宜。 The instruments should be tuned up before each performance. 每次演出开始前都应将乐器调好音。来自《简明英汉词典》

6 stimulants
n.兴奋剂( stimulant的名词复数 )；含兴奋剂的饮料；刺激物；激励物
参考例句：
Coffee and tea are mild stimulants. 咖啡和茶是轻度兴奋剂。 At lower concentrations they may even be stimulants of cell division. 在浓度较低时，它们甚至能促进细胞分裂。来自辞典例句

7 cognitive
adj.认知的，认识的，有感知的
参考例句：
As children grow older,their cognitive processes become sharper.孩子们越长越大，他们的认知过程变得更为敏锐。 The cognitive psychologist is like the tinker who wants to know how a clock works.认知心理学者倒很像一个需要通晓钟表如何运转的钟表修理匠。

8 distraction
n.精神涣散，精神不集中，消遣，娱乐
参考例句：
Total concentration is required with no distractions.要全神贯注，不能有丝毫分神。 Their national distraction is going to the disco.他们的全民消遣就是去蹦迪。

9 lobe
n.耳垂，（肺，肝等的）叶
参考例句：
Tiny electrical sensors are placed on your scalp and on each ear lobe.小电器传感器放置在您的头皮和对每个耳垂。 The frontal lobe of the brain is responsible for controlling movement.大脑前叶的功能是控制行动。