单选题 The most complex object known to humanity is the human brain—and not only is it complex, hut it is the seat of one of the few natural phenomena that science has no purchase on at all, namely consciousness. To try to replicate something that is so poorly understood may therefore seem like hubris. But you have to start somewhere, and IBM and the Ecole Polytechnique Federale de Lausanne (EPFL), in Switzerland, propose to start by replicating "in silico", as the jargon has it, one of the brain"s building blocks.
In a partnership announced on June 6th of 2005, the two organizations said they would be working together to build a simulation of a structure known as a neo-cortical column on a type of IBM supercomputer that is currently used to study the molecular functioning of genes. If that works, they plan to use future, more powerful computers to link such simulated columns together into something that mimics a brain.
In a real brain, a neo-cortical column is a cylindrical element about a third of a millimeter in diameter and three millimeters long, containing some 10,000 nerve cells. It is these columns, arranged side by side like the cells of a honeycomb, which make up the famous "grey matter" that has become shorthand for human intelligence. The Blue Gene/L supercomputer that will be used for the simulation consists of enough independent processors for each to be programmed to emulate an individual nerve cell in a column.
The EPFL"s contribution to the Blue Brain Project, as it has inevitably been dubbed, will be to create a digital description of how the columns behave. Its Brain Mind Institute has what is generally regarded as the world"s most extensive set of data on the machinations of the neo-cortex—the columns" natural habitat and the part of the brain responsible for learning, memory, language and complex thought. This database will provide the raw material for the simulation. Biologists and computer scientists will then collaborate to connect the artificial nerve cells up in a way that mimics nature. They will do so by assigning electrical properties to them, and telling them how to communicate with each other and how they should modify their connections with one another depending on their activity.
That will be no mean feat. Even a single nerve cell is complicated, not least because each one has about 10,000 connections with others. And nerve cells come in great variety—relying, for example, on different chemical transmitters to carry messages across those connections. Eventually, however, a digital representation of an entire column should emerge.
This part of the project is expected to take two to three years. From then on, things will go in two directions simultaneously. One will be to "grow" more columns (the human brain contains about 1 million of them) and get them to interact with one another. The second will be to work at a more elementary level—that is, to simulate the molecular structure of the brain, and to look at the influence of gene expression on brain function.
Assuming that the growth of computing power continues to follow Moore"s Law, Charles Peck, the leader of IBM"s side of the collaboration, reckons it should be feasible to emulate an entire human brain in silico this way in ten to fifteen years. Such an artificial brain would, of course, be a powerful research tool. It would allow neurological experiments that currently take days in a "web lab" to be conducted in seconds. The researchers hope, for instance, that their simulated brain will reveal the secrets of how certain psychiatric and neurological disorders develop. But that is probably not the real reason for doing it. The most interesting questions, surely, are whether such an artificial brain will be intelligent, or conscious, or both.
单选题 Which of the following is NOT true about a neo-cortical column?
【正确答案】 C
【答案解析】[解析] 第3段第1句提到,在真正的大脑里,新皮质柱是一个……的圆柱形元件,由此可知,真实的人类大脑是有新皮质柱这样东西的,C说“它是一种仿生结构”与文意不符,故为答案。同时该句说到皮质柱是一个圆柱形的元件(a cylindrical element),且包含约1万个神经细胞(containing some 10,000 nerve cells),A正确。接着第2句说到新皮质柱构成灰质,而灰质则是人类智能的简称,因此D也正确。第2段讲到这两家机构将合作在计算机上通过模拟新皮质柱来建模,并有望在未来模拟出人类的大脑,故B也正确。
单选题 What does the sentence "That will be no mean feat" in the fifth paragraph stands for?
【正确答案】 D
【答案解析】[解析] 该句在文中起承上启下的作用:上文讲科学家试图将人造神经细胞连接起来,下文却指出神经细胞结构复杂,由此可知该句是在暗示“连接人造神经并非易事”,故D正确。
单选题 Which category of writing does the review belong to?
【正确答案】 D
【答案解析】[解析] 本文主要介绍两家科研机构合作的课题,即大脑构建计算机模型。接着文章又依次叙述了这一课题的原理、流程以及功能,且许多关于大脑的知识也在文中有所体现。据此可知本文是说明文,故选D。