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成人大脑如何学新而不忘旧(下)
- Authors
为了寻找丝状伪足，三位研究人员使用了一种名为"电子显微放射自显影法"（eMAP）的灵敏显微镜成像技术。
双语精读
To carry out their search for filopodia, the trio used a sensitive microscopy technique called eMAP. They studied 2,234 synapses between cortical nerve cells of a type called pyramidal neurons, which have thousands of synapses each.
为了寻找丝状伪足，三位研究人员使用了一种名为"电子显微放射自显影法"（eMAP）的灵敏显微镜成像技术。一种名为椎体神经元的皮层神经细胞每个都有数千个突触，他们研究了其中的2234个。
Peering through an emap microscope is enough to determine which cellular protrusions are filopodia. But it cannot show which synapses on them are silent. To do that, they needed to test how the filopodia responded to glutamate, the brain's main excitatory neurotransmitter.
通过eMAP显微镜观察就可以确定哪些细胞突起是丝状伪足，但并不能显示上面的哪些突触处于沉默状态。要确定这一点，他们需要测试丝状伪足对谷氨酸的反应，谷氨酸也就是大脑主要的兴奋性神经递质。
First, they had to deliver a controlled flow of glutamate to the particular synapse they wanted to test. To this end, they poured a soup of "caged" glutamate over the neuron under examination. This form of the molecule is inert until hit with energy from the intersection of two laser beams.
首先，他们必须向想要测试的特定突触输送一定量的谷氨酸。为此，他们在被测试的神经元上倒入"束缚态"的谷氨酸溶液。这种状态下的谷氨酸分子是惰性的，在两束激光交汇的能量冲击下才会被激活。
Aiming those at the synapse under study enabled them to uncage the neurotransmitter and see, by measuring the electrical activity in that part of the neuron using an ultrafine electrode, whether the synapse responded.
将激光对准待研究的突触，可以释放出谷氨酸这种神经递质，研究人员通过使用超细电极测量神经元对应部分的电活动，就可以观察突触是否有反应。
They found that mature pyramidal-neuron protrusions generated electrical activity when exposed to glutamate, as expected. Filopodia did not, confirming the silence of their synapses.
他们发现，接触到谷氨酸时，成熟的锥体神经元突起产生了电活动，与预期一致。但丝状伪足没有活动，证实了其突触的沉默状态。
Silent synapses are, however, useless unless they can be switched on at the appropriate moment. And the researchers confirmed this is possible.
然而，沉默的突触是没有用的，除非能在适当的时候被激活。研究人员已经证实这是可行的。
They were able to induce the silent versions on filopodia to turn into mature, active synapses by pairing the simulated release of glutamate with a subsequent surge of electricity inside the neuron.
他们想办法让一种对释放谷氨酸的模拟在神经元内产生电涌，从而诱导丝状伪足上的沉默突触转化为最成熟、活跃的突触。
This pairing of events caused silent synapses to start, within minutes, displaying receptor molecules characteristic of active synapses. The same pairing, applied to mature synapses, did nothing.
在这种操作的诱导下，沉默突触在几分钟内便开始表现出活跃突触的受体分子特征，同样的操作却没有对成熟突触产生任何作用。
The researchers thereby show that it is hard to get a mature synapse to change the strength of its connection (thus satisfying the stability side of the dilemma), but easy to unsilence a silent one (satisfying the plasticity side).
研究人员由此确定，成熟突触的连接强度难以改变（从而满足了两难困境中的稳定性的要求），但要激活沉默突触却很容易（满足了可塑性的要求）。
The next thing to investigate is how, why and when new filopodia appear.
下一步要研究的就是新的丝状伪足是如何、为何以及何时出现的。
The discovery of all these eager-to-learn silent synapses and filopodia, Dr Harnett says, "is a lever for us to get into understanding learning in adults and how potentially we can get access to make it not degrade over the course of ageing or disease".
哈尼特博士说，所有这些"求知若渴"的沉默突触和丝状伪足的发现，"为我们提供了一种手段来了解成年人的学习能力、以及如何能够通过某种干预，使其不随衰老或疾病发展而退化"。
词汇预习
release [高考]
美[rɪˈliːs] | 英[rɪˈliːs]
n. 释放；让渡；发行 vt. 释放；让与；准予发表；发射
investigate [高考]
美[ɪnˈvestɪɡeɪt] | 英[ɪnˈvestɪɡeɪt]
v. 调查；研究
molecule [高考]
美[ˈmɑːlɪkjuːl] | 英[ˈmɒlɪkjuːl]
n. 分子；微粒
nerve [高考]
美[nɜːrv] | 英[nɜːv]
n. 神经；勇气；敏感处；叶脉；厚脸皮 v. 鼓起勇气
degrade [高考]
美[dɪˈɡreɪd] | 英[dɪˈɡreɪd]
v. 降格；使屈辱；贬低；退化；降解
thereby [高考]
美[ˌðerˈbaɪ] | 英[ˌðeəˈbaɪ]
adv. 因此；从而
stability [高考]
美[stəˈbɪləti] | 英[stəˈbɪləti]
n. 稳定性；居于修道院
induce [高考]
美[ɪnˈduːs] | 英[ɪnˈdjuːs]
vt. 引起；促使；劝服；引诱
within [高考]
美[wɪˈðɪn] | 英[wɪˈðɪn]
prep. 在(某段时间、距离或范围)内；在…里面 adv. 在…里面 n. 内部
determine [高考]
美[dɪˈtɜːrmɪn] | 英[dɪˈtɜːmɪn]
v. 决定；决心；确定；测定
thus [高考]
美[ðʌs] | 英[ðʌs]
adv. 这样；如此；因此；从而
deliver [高考]
美[dɪˈlɪvər] | 英[dɪˈlɪvə(r)]
v. 递送；发表（演讲）；交付；解救；生（孩子）；接生；履行；投掷
technique [高考]
美[tekˈniːk] | 英[tekˈniːk]
n. 技术；技巧；技能
access [高考]
美[ˈækses] | 英[ˈækses]
n.入口，通道；获得的机会，使用权；（对计算机存储器的）访问，存取；（情感）爆发，发作；探视权 v. 接近，进入；获取，访问（计算机信息） adj.[美]（电视节目或时间等）对外公开的
sensitive [高考]
美[ˈsensətɪv] | 英[ˈsensətɪv]
adj. 灵敏的；敏感的；感光的；易受伤害的；善解人意的 n. 敏感的人
eager [高考]
美[ˈiːɡər] | 英[ˈiːɡə(r)]
adj. 热切的；渴望的
characteristic [高考]
美[ˌkærəktəˈrɪstɪk] | 英[ˌkærəktəˈrɪstɪk]
n. 特点；特性；特色 adj. 典型的；特有的
appropriate [高考]
美[əˈproʊpriət , əˈproʊprieɪt] | 英[əˈprəʊpriət , əˈprəʊprieɪt]
adj. 适当的；相称的 vt. 占用；拨出(款项)
electrical [高考]
美[ɪˈlektrɪkl] | 英[ɪˈlektrɪkl]
adj. 电的；与电有关的
mature [高考]
美[məˈtʃʊr] | 英[məˈtʃʊə(r)]
adj. 成熟的；(保单）到期的；考虑周到的 v. 成熟；长成
dilemma [高考]
美[dɪˈlemə] | 英[dɪˈlemə]
n. 困境；进退两难
microscope [高考]
美[ˈmaɪkrəskoʊp] | 英[ˈmaɪkrəskəʊp]
n. 显微镜
access to [高考]
美[ˈæksɛs tu] | 英[ˈækses tu:]
接近，有权使用；进入，通向…的路口
subsequent [高考]
美[ˈsʌbsɪkwənt] | 英[ˈsʌbsɪkwənt]
adj. 随后的；后来的
laser [四级]
美[ˈleɪzər] | 英[ˈleɪzə(r)]
n. 激光；镭射
lever [四级]
美[ˈlevər] | 英[ˈliːvə(r)]
n. 杠杆；控制杆；手段 v. 撬开；使用杠杆
surge [四级]
美[sɜːrdʒ] | 英[sɜːdʒ]
n. 汹涌；波涛；猛增 v. 汹涌；涌起；激增；[海]缆绳滑脱
potentially [四级]
美[pə'tenʃəli] | 英[pə'tenʃəli]
adv. 潜在地
receptor [四级]
美[rɪˈseptər ] | 英[rɪˈseptə(r)]
n. 感受器；受体；接受器；受话器
make it [四级]
美[mek ɪt] | 英[meik it]
成功 达到预定目标,性交易,幸存
in that [四级]
美[ɪn ðæt] | 英[in ðæt]
因为，由于，既然
characteristic of [四级]
美 | 英
特有的； 表示 ... 特性的
under study [四级]
美 | 英
adj. 在研究中(所研究的)
electrode [六级]
美[ɪˈlektroʊd] | 英[ɪˈlektrəʊd]
n. 电极；电焊条
inert [专四]
美[ɪˈnɜːrt] | 英[ɪˈnɜːt]
adj. 无行动的；惰性的；迟钝的
learning [专八]
美[ˈlɜːrnɪŋ] | 英[ˈlɜːnɪŋ]
n. 学问；学识；学习
intersection [考研]
美[ˌɪntərˈsekʃn] | 英[ˌɪntəˈsekʃn]
n. 交集；十字路口；交叉点
neuron [托福]
美[ˈnʊrɑːn] | 英[ˈnjʊərɒn]
n. 神经元；神经细胞
microscopy [托福]
美[maɪˈkrɑskəpi] | 英[maɪˈkrɒskəpi]
n. 显微镜学；用显微镜检查
glutamate [雅思]
美[ˈɡlutəˌmet] | 英['glu:təˌmeɪt]
n. 【生化】谷氨酸盐，谷氨酸酯
重点讲解
To carry out their search for filopodia, the trio used a sensitive microscopy technique called eMAP. They studied 2,234 synapses between cortical nerve cells of a type called pyramidal neurons, which have thousands of synapses each.
为了寻找丝状伪足，三位研究人员使用了一种名为"电子显微放射自显影法"（eMAP）的灵敏显微镜成像技术。一种名为椎体神经元的皮层神经细胞每个都有数千个突触，他们研究了其中的2234个。
carry out 执行，实行
（英文释义：If you carry out a threat, task, or instruction, you do it or act according to it.）
【例】Police say they believe the attacks were carried out by nationalists.
警方称他们认为这些袭击行为是民族主义分子发动的。
trio n. （尤指演奏或演唱的）三人小组；三件套
【例】...classy American songs from a Texas trio.
…来自德克萨斯州三重唱小组的时髦的美国歌曲。
【拓展】duo n. 二重奏；二重唱；二人组
【例】the comedy duo Laurel and Hardy 劳莱和哈代这对喜剧搭档
Peering through an emap microscope is enough to determine which cellular protrusions are filopodia. But it cannot show which synapses on them are silent. To do that, they needed to test how the filopodia responded to glutamate, the brain's main excitatory neurotransmitter.
通过eMAP显微镜观察就可以确定哪些细胞突起是丝状伪足，但并不能显示上面的哪些突触处于沉默状态。要确定这一点，他们需要测试丝状伪足对谷氨酸的反应，谷氨酸也就是大脑主要的兴奋性神经递质。
peer v. & n.
1. 作动词，费力地看；盯着
（英文释义：to look closely or carefully at sth, especially when you cannot see it clearly）
【例】We peered into the shadows. 我们往阴暗处仔细瞧。
2. 身份（或地位）相同的人；同龄人；同辈
（英文释义：Your peers are the people who are the same age as you or who have the same status as you.）
【例】Peer pressure is strong among young people. 年轻人受到强大的同辈压力
First, they had to deliver a controlled flow of glutamate to the particular synapse they wanted to test. To this end, they poured a soup of "caged" glutamate over the neuron under examination. This form of the molecule is inert until hit with energy from the intersection of two laser beams.
首先，他们必须向想要测试的特定突触输送一定量的谷氨酸。为此，他们在被测试的神经元上倒入"束缚态"的谷氨酸溶液。这种状态下的谷氨酸分子是惰性的，在两束激光交汇的能量冲击下才会被激活。
to this end 为了这个目的
（英文释义：as a way of dealing with or doing something）
【例】We want to save the building. To this end, we have hired someone to assess its current state.
我们想拯救这座建筑。为此，我们已经雇人对其现状进行评估。
inert adj. 无活动能力的，无行动力的；惰性的；不活泼的
（英文释义：without power to move or act；without active chemical or other properties）
【例】He lay inert with half-closed eyes.
他半睁着双眼一动不动地躺着。
intersection n. 十字路口；交叉路口；交点
【例】Traffic lights have been placed at all major intersections.
所有重要的交叉路口都安装了交通信号灯。
Aiming**** those at**** the synapse under study enabled them**** to**** uncage**** the neurotransmitter**** and see,**** by**** measuring the electrical**** activity**** in**** that**** part**** of**** the neuron**** using an**** ultrafine electrode,**** whether the synapse responded.****
将激光对准待研究的突触，可以释放出谷氨酸这种神经递质，研究人员通过使用超细电极测量神经元对应部分的电活动，就可以观察突触是否有反应。
They**** found that**** mature**** pyramidal-neuron**** protrusions generated electrical**** activity**** when**** exposed to**** glutamate,**** as**** expected****.**** Filopodia did not,**** confirming**** the silence of**** their synapses****.****
他们发现，接触到谷氨酸时，成熟的锥体神经元突起产生了电活动，与预期一致。但丝状伪足没有活动，证实了其突触的沉默状态。
Silent synapses are, however, useless unless they can be switched on at the appropriate moment. And the researchers confirmed this is possible.
然而，沉默的突触是没有用的，除非能在适当的时候被激活。研究人员已经证实这是可行的。
switch on 接通，开启
（英文释义：If you switch on a light or other electrical device, you make it start working by operating a switch.）
【例】She emptied both their mugs and switched on the electric kettle.
她倒空了他们俩的杯子，然后打开了电水壶。
【拓展】be switched on 变得兴奋、活泼
（英文释义：To become animated, lively, and alert, especially suddenly or on short notice.）
【例】She's such a quiet, reserved woman most of the time, but she really switches on when we all go out for dancing on the weekends.
她大部分时间都是一个沉默寡言的女人，但当我们周末出去跳舞时，她真的变得很兴奋。
They were able to induce the silent versions on filopodia to turn into mature, active synapses by pairing the simulated release of glutamate with a subsequent surge of electricity inside the neuron.
他们想办法让一种对释放谷氨酸的模拟在神经元内产生电涌，从而诱导丝状伪足上的沉默突触转化为最成熟、活跃的突触。
induce v.
1. 引起
（英文释义：To induce a state or condition means to cause it.）
【例】Doctors said surgery could induce a heart attack.
医生们说手术可能导致心脏病。
2. 引诱; 劝说
（英文释义：If you induce someone to do something, you persuade or influence them to do it.）
【例】Nothing would induce me to take the job.
没有什么能诱使我接受这份工作。
This**** pairing of**** events**** caused**** silent**** synapses**** to**** start,**** within**** minutes,**** displaying**** receptor**** molecules characteristic**** of**** active**** synapses****.**** The same**** pairing,**** applied to**** mature**** synapses****,**** did nothing.****
在这种操作的诱导下，沉默突触在几分钟内便开始表现出活跃突触的受体分子特征，同样的操作却没有对成熟突触产生任何作用。
The researchers thereby show**** that**** it**** is**** hard**** to**** get a mature**** synapse to**** change**** the strength**** of**** its connection**** (thus satisfying**** the stability side**** of**** the dilemma), but easy**** to**** unsilence a silent**** one (satisfying the plasticity**** side****).
研究人员由此确定，成熟突触的连接强度难以改变（从而满足了两难困境中的稳定性的要求），但要激活沉默突触却很容易（满足了可塑性的要求）。
The next thing to investigate is how, why and when new filopodia appear.
下一步要研究的就是新的丝状伪足是如何、为何以及何时出现的。
lever n. & v.
1. 作名词
（1）（车辆或机器的）操纵杆，控制杆
【例】Pull the lever towards you to adjust the speed.
把操纵杆向你身体一侧拉动以调节速度。
（2）（用于达到某一目的的）手段，方法
【搭配】a lever for/ against sth 支持／反对的措施／手段
【例】The threat of sanctions is our most powerful lever for peace.
实施制裁的威胁是我们争取和平最有力的施压手段。
2. 作动词，（用杠杆）撬动
【例】I levered the lid off the pot with a knife.
我用刀撬掉了罐盖。
【拓展】leverage n.
1. 影响力
（英文释义：Leverage is the ability to influence situations or people so that you can control what happens.）
【例】diplomatic leverage 外交影响力
His position as mayor gives him leverage to get things done.
他的市长身份使他有能力办成一些事情。
2. 杠杆作用，杠杆力
3. 金融杠杆
get/gain access to 获得，接近，可以使用
（英文释义：to succeed in entering a place or in seeing someone or something）
【例】You are allowed to get access to our computer system only if you get the manager's permission.
只要得到经理的许可，你就可以使用我们的电脑系统。
degrade v.
1. 使贬低身份; 使有辱人格
【例】This poster is offensive and degrades women.
这张海报冒失无礼，有辱女性尊严。
2. 使恶化，使退化
【例】...the ability to meet human needs indefinitely without degrading the environment.
…满足人类无限需求但又不会使环境恶化的能力。
【拓展】degrading adj. 有辱人格的；降低身份的
degradable adj. 可降级的；可降低的
The discovery of all these eager-to-learn silent synapses and filopodia, Dr Harnett says, "is a lever for us to get into understanding learning in adults and how potentially we can get access to make it not degrade over the course of ageing or disease".
哈尼特博士说，所有这些"求知若渴"的沉默突触和丝状伪足的发现，"为我们提供了一种手段来了解成年人的学习能力、以及如何能够通过某种干预，使其不随衰老或疾病发展而退化"。
lever n. & v.
1. 作名词
（1）（车辆或机器的）操纵杆，控制杆
【例】Pull the lever towards you to adjust the speed.
把操纵杆向你身体一侧拉动以调节速度。
（2）（用于达到某一目的的）手段，方法
【搭配】a lever for/ against sth 支持／反对的措施／手段
【例】The threat of sanctions is our most powerful lever for peace.
实施制裁的威胁是我们争取和平最有力的施压手段。
2. 作动词，（用杠杆）撬动
【例】I levered the lid off the pot with a knife.
我用刀撬掉了罐盖。
【拓展】leverage n.
1. 影响力
（英文释义：Leverage is the ability to influence situations or people so that you can control what happens.）
【例】diplomatic leverage 外交影响力
His position as mayor gives him leverage to get things done.
他的市长身份使他有能力办成一些事情。
2. 杠杆作用，杠杆力
3. 金融杠杆
get/gain access to 获得，接近，可以使用
（英文释义：to succeed in entering a place or in seeing someone or something）
【例】You are allowed to get access to our computer system only if you get the manager's permission.
只要得到经理的许可，你就可以使用我们的电脑系统。
degrade v.
1. 使贬低身份; 使有辱人格
【例】This poster is offensive and degrades women.
这张海报冒失无礼，有辱女性尊严。
2. 使恶化，使退化
【例】...the ability to meet human needs indefinitely without degrading the environment.
…满足人类无限需求但又不会使环境恶化的能力。
【拓展】degrading adj. 有辱人格的；降低身份的
degradable adj. 可降级的；可降低的
课后练习
How did the researchers find silent synapses?
A. They used emap to determine silent synapses in pyramidal neurons.
B. They used glutamate to induce respondence in the synapses.
C. They used two laser beams to activate the potential filopodia.
D. They used ultrafine electrode to uncage neurotransmitters.
What did the researchers find?
A. Filopodia can respond to glutamate.
B. Silent synapses can be activated.
C. Filopodia can be connected to mature neurons.
D. Simulated glutamate can produce electricity.
How can silent synapses help the brain strike a balance?
A. They can facilitate the reception of new information.
B. They can send more molecules to mature synapses.
C. They can be activated when mature synapses remain stable.
D. They can strengthen their connection with mature synapses.
According to Dr. Harnett, the discovery of silent synapses ____.
A. explains when new filopodia appear
B. is key to cultivating interest in learning
C. enables adults to change their learning methods
D. can help prevent learning degradation in adults.