Question

    The brain has a powerful ability to remember and connect events separated in time. And now, in that new study in mice published in Neuron, scientists at Columbia’s Zuckerman Institute have cast light on how the brain can form lasting links.

The hippocampus-a small, seahorse-shaped region buried deep in the brain-is an important headquarters for learning and memory. Previous experiments in mice showed that disruption (中断) to the hippocampus leaves the animals with trouble learning to associate two events separated by tens of seconds.

“The traditional view has been that cells in the hippocampus keep up a level of continuous activity to associate such events,” said Dr. Ahmed, co-first author of the study. “Turning these cells off would thus disrupt learning.”

To test this view, the researchers imaged parts of the hippocampus of mice as the animals were exposed to two different stimuli (刺激物): a neutral (神经的) sound followed by a small but unpleasant puff of air. A fifteen-second delay separated the two events. The scientists repeated this experiment across several trials. Over time, the mice learned to associate the sound with the soon-to-follow puff of air. Using advanced microscopy, they recorded the activity of thousands of neurons (神经元) , a type of brain cell, in the animals’ hippocampus over the course of each trial for many days.

“We expected to see continuous neural activity that lasted during the fifteen-second gap, an indication of the hippocampus at work linking the auditory sound and the air puff,” said computational neuroscientist Stefano Fusi, PhD. “But when we began to analyze the data, we saw no such activity.” Instead, the neural activity recorded during the fifteen-second time gap was sparse (稀少的). Only a small number of neurons worked, and they did so seemingly at random.

To understand activity, they had to shift the way they analyzed data and use tools designed to make sense of random processes. Finally, the researchers discovered a complex pattern in the randomness: a style of mental computing that seems to be a remarkably efficient way that neurons store information.

“We were happy to see that the brain doesn’t maintain ongoing activity over all these seconds because that’s not the most efficient way to store information,” said Dr. Ahmed. “The brain seems to have a more efficient way to build this bridge.”

1.What can we learn about the hippocampus?

A.It weakens with the memory decline.

B.It is a brain region crucial for memory.

C.It serves as a tool of learning languages.

D.It is involved in the visual area of the brain.

2.According to the passage, the traditional view is that ______.

A.associations of events require continuous neural activity

B.animals have trouble learning to associate two events

C.neural activity can hardly be replaced by associations

D.a 15-second delay is enough to separate two events

3.The new study in mice indicates that ______.

A.continuous activity happens as expected

B.no neurons stay active at intervals of 15 seconds

C.a complex pattern helps the brain learn associations

D.neuronal information is stored in well-designed tools

4.From the last two paragraphs, we can infer that the findings ______.

A.inspire deeper explorations of disorders

B.provide evidence for language learning

C.build a bridge between different parts of the brain

D.help map some aspects of a person’s experiences

Answer

1.B

2.A

3.C

4.A

【解析】

本文是说明文。文章主要通过一项研究，揭示大脑如何形成持久的联系。这些发现除了帮助绘制联想学习的电路图外，还为更深入地探索诸如恐慌和创伤后应激障碍等疾病提供了一个起点。

1.

细节理解题。根据第二段的The hippocampus-a small, seahorse-shaped region buried deep in the brain-is an important headquarters for learning and memory. (海马一个小的，海马状的区域埋在大脑深处,是学习和记忆的重要总部)可知，海马是一个对记忆至关重要的大脑区域。crucial对应文中important headquarters。故选B。

2.

细节理解题。根据第三段的The traditional view has been that cells in the hippocampus keep up a level of continuous activity to associate such events(传统的观点是，海马体中的细胞保持一定水平的连续活动来关联这些事件)可知，事件的关联需要持续的神经活动，因此选A项 associations f events require continuous neural activity, require对应文中的to表目的,这里将句式转换了一下。其它选项都是第四段 test the view的实验过程或发现,和问题不符。故选A。

3.

细节理解题。根据六段的Finally, the researchers discovered a complex pattern in the randomness: a style of mental computing that seems to be a remarkably efficient way that neurons store information.(最后，研究人员在随机性中发现了一个复杂的模式：一种精神计算方式，似乎是神经元存储信息的一种非常有效的方式)可知,一个复杂的模式有助于大脑学习联想， 故选C: a complex pattern.正确。故选C。

4.

推理判断题。根据第八段第64题A根据第八段In addition to helping to map the circuitry involved in associative learning, these findings also provide a starting point to more deeply explore disorders, such as panic and post-traumatic stress disorder.(除了帮助绘制联想学习的电路图外，这些发现还为更深入地探索诸如恐慌和创伤后应激障碍等疾病提供了一个起点)可推断，这个发现鼓舞更深入探索紊乱。故选A。