经济学人下载:绘制大脑活动地图 棘手的细胞

Science and technology
科学技术

The Brain Activity Map
绘制大脑活动地图

Hard cell
棘手的细胞

An ambitious project to map the brain is in the works. Possibly too ambitious
一个绘制大脑活动地图的宏伟计划正在准备当中，或许有些太宏伟了

NEWS of what protagonists hope will be America's next big science project continues to dribble out.
有关其发起人心中下一个科学大工程的新闻报道层出不穷。

A leak to the New York Times, published on February 17th, let the cat out of the bag, with a report that Barack Obama's administration is thinking of sponsoring what will be known as the Brain Activity Map.
2月17日，《纽约时报》刊登的一位线人报告终于泄露了秘密，报告称奥巴马政府正在考虑赞助将被称为大脑活动地图的计划。

And on March 7th several of those protagonists published a manifesto for the project in Science.
3月7日，部分发起人在《科学》杂志上发表声明证实了这一计划。

The purpose of BAM is to change the scale at which the brain is understood.
大脑活动地图计划的目标是改变人们在认知大脑时采用的度量方法。

At the moment, neuroscience operates at two disconnected levels.
眼下，神经学的研究处在两个断开的层次。

The higher one, where the dimensions of features are measured in centimetres, has many techniques at its disposal, notably functional magnetic-resonance imaging, which measures changes in tissues' fuel consumption.
在相对宏观的层次当中各个特征的规模用厘米来衡量，有很多技术可以使用，尤其是用来测量组织中能量消耗变动情况的核磁共振成像技术。

This lets researchers see which bits of the brain are active in particular tasks—as long as those tasks can be performed by a person lying down inside a scanner.
该技术可使研究人员找出在完成具体的任务时，大脑的哪些部分处于活跃状态。

At the other end of the scale, where features are measured in microns, lots of research has been done on how individual nerve cells work, how messages are sent from one to another, and how the connections between cells strengthen and weaken as memories are formed.
而另一个度量的层次则要求用微米来测量各种特征，这一层次的研究很多都是关于单个神经细胞是如何工作的、信息在神经细胞之间是如何传递的以及当产生记忆的时候神经细胞之间的联系是如何得到加强和减弱的。

Between these two, though, all is darkness.
然而，位于这两个层次之间的研究还处于一片漆黑当中。

It is like trying to navigate America with an atlas that shows the states, the big cities and the main highways, and has a few street maps of local neighbourhoods, but displays nothing in between.
这就好比当你要在美国寻找自己的前进方向时，手里却只有一副如下的地图册：上面只显示各州轮廓、各都市的坐落点、干线公路以及一些社区街道，除此之外别无它物。

BAM, if all goes well, will yield plans of entire towns and villages, and start to fill in the road network.
如果大脑活动地图计划进展顺利的话，就能得到完整的城市和村落规划图，道路网也将完善。

It will also, to push the analogy to breaking point, let a user look at actual traffic flows on the roads in question, and even manipulate the road signs, in order to understand how particular communities work.
它还能使用户能够看到自己备选道路的实际交通情况，甚至还能通过操纵道路标志来了解具体地区是怎样运作的，将脑图、地图这一类比给打破。

The mappers' aim is to find out how nerve cells collaborate to process information.
制图者的目标是找出神经细胞是如何共同处理信息的。

That means looking at the connections between hundreds, thousands and even millions of adjacent cells—and doing so, crucially, while those cells are still alive, rather than after they have been sliced and diced for microscopic examination.
这就意味着要研究成百上千甚至上百万的相邻细胞之间有何种关联，关键在于这一研究还要在这些细胞存活的时候进行，而不是把它们切片后放在显微镜下观察。

This will require a new set of tools.
要做到这一点就需要一套新的工具。

And the guts of the BAM proposal are that the American taxpayer should provide those tools.
大脑活动地图提案的大胆之处在于它认为美国纳税人应该出钱提供这些工具。

It is thus no coincidence that the lead author of the paper, Paul Alivisatos, the director of the Lawrence Berkeley National Laboratory, is a materials scientist, not a neuroscientist.
因此，由材料学家保罗?阿里维萨多而非神经学家来主笔该提案并非什么巧合。

Dr Alivisatos and his ten colleagues would like their new tools to be able to record, simultaneously, the activity of millions of nerve cells.
阿里维萨多博士和他的10个同事希望他们的新工具能同时记录数百万神经细胞的活动情况；

Then, having done the recording, they would like a second toolkit that lets them manipulate each cell at will, to see what effect that has on the rest of the circuit.
做完记录后，他们还想要能自由操纵每个神经细胞的第二套工具，以便找出这样的操作对细胞周围有何影响；

Finally, to handle the uNPRecedented amounts of data that the first and second steps will generate, they would like a new set of computing hardware and software.
最后，为了处理前面两个步骤所产生的空前的海量数据，他们还想要一套新的计算机软硬件。

A modest proposal, then.
如此看来这提案还不算过分嘛，

And one which is inducing polite scepticism from many neuroscientists who are not part of the charmed circle, and who fear their subject is about to be sacrificed to a juggernaut.
但它却也引来了许多此小圈子外的神经学家客气的猜疑，他们担心实验被试会成为这一计划的牺牲品。

Such scepticism is reasonable.
这种怀疑是合乎情理的。

The third part of the project, the computer side, should be doable.
该计划的计算机部分是可行的，不论如何，这只不过是提高计算机的原有水平而已。

That is just a question of pushing harder in a direction things are, in any case, going.
但是前面两部分你要怎么完成呢？谁都不知道。

How you would do the first two, though, is anybody's guess—and Dr Alivisatos and his colleagues are pretty sketchy about the details.
而且阿里维萨多和其同事对相关细节也说得相当笼统。

Thinking big, thinking small
高瞻远瞩也要低头看路

What ideas there are draw heavily on the nascent field of nanotechnology.
现在能想到的办法主要就是利用纳米技术这一新领域，

This is Dr Alivisatos's particular province, and also that of the Kavli Foundation, which exists to advance fundamental research in the fields of astrophysics, nanoscience, neuroscience and theoretical physics.
这是阿里维萨多的专攻领域，也是美国科威利基金会专门支持的领域。该基金会的宗旨是推动天体物理学、纳米技术、神经学和理论物理学等领域的基础研究，

A brain map would push two of those buttons, which accounts for the fact that five of the manifesto's authors work for institutes sponsored by this foundation.
一个大脑地图计划就会涉及到里面的两个领域，这也解释了《科学》杂志上的声明人中有五个在该基金赞助的机构工作这一事实。

But any successes that nanotechnology has enjoyed so far have been small beer compared with the devices that would be needed to interrogate nerve cells, record the results and transmit them back to base, let alone tell those nerve cells what to do.
但是，和审问神经细胞、记录审问结果并将审问结果传回大本营所需要的设备相比，目前纳米技术领域所取得一切成果都是些小把戏，就更别指望能用它来控制神经细胞的行为了。

The protagonists would, they say, build up slowly, using humbler creatures than human beings as experimental subjects to start with.
该计划的发起人说，他们会慢慢推进，首先使用比人类低级的生物作为实验对象。

This was the approach taken by the Human Genome Project, which began with bacteria and yeast, progressed to worms, flies and mice, and only then tackled people.
人类基因组工程当初便是采取的这一途径：一开始是细菌和酵母，再升级到蠕虫、苍蝇和老鼠，最后才是人类。

But the analogy is not quite a fair one.
但拿它做类比还不大合适，

When the genome project started,genomicists already had a basic understanding of how to go about it.
因为在基因组工程启动时，遗传学家对该如何进行已经有了一个基本理解，

That understanding was vastly refined and improved by the application of several billion dollars.
这一理解在花费了数十亿美元后得到了大大的提炼和改善。

But it was there from the beginning.
但人家一开始就有理解啊。

Going from existing methods of recording and manipulating cell activity, which rely on large electrodes, often connected to the outside world by physical wires, to the massively parallel, wireless system envisaged by Dr Alivisatos, is a different proposition.
记录和操纵细胞活动的现有技术要依靠一些很大的电极，从这些技术跨越到阿里维萨多博士所设想的无线平行体系，相对基因组计划而已，则是一个不同的命题。

It may be possible. But it requires a leap of faith.
这也许是可能的，但要让人相信则需要信心的大飞跃。

The next few weeks will reveal whether that faith is shared by a cash-strapped president.
囊中羞涩的总统是否也有这种信心呢？答案将会在后面的几周内揭晓。