题目内容：

    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.”

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.

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.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

3.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