VOA慢速英语--科学家训练老鼠开车他们学到了什么?

（单词翻译）

Scientists Trained Rats to Drive Cars. What Did They Learn?

Mice and rats have long been used in medical research because of their biological similarities to humans.

The tiny animals have already shown an ability to recognize objects, push buttons and find their way through complex paths.

Now, scientists have trained rats to drive small vehicles created for them. One of the main findings¹ of the experiment was that the driving activity seemed to help the rats relax.

Researchers at the University of Richmond in Virginia led the experiment. Their findings were published in Behavioural Brain Research.

The team built tiny cars out of plastic and other materials. The vehicles had an opening at one end where electrical wires were attached. By touching² one of three different wires, the rat could steer³ the car in different directions – left, center and right.

Sweet treats were placed inside the experiment containers in an attempt to get the rats to drive the vehicle to get to the food.

Researchers trained 17 rats over several months to drive around the containers. The animals proved that they could be trained to drive forward as well as in other directions to get to the treats.

Kelly Lambert of the University of Richmond helped lead the experiment. She told the French news agency⁴ AFP the research suggests that rat brains may be more complex and flexible than once thought.

Lambert said she had long been interested in neuroplasticity, or the way the brain changes to react to different experiences and difficulties. She found that rats kept in what she calls "enriched⁶ environments" performed far better than those in labs. While she expected that result, Lambert told AFP "it was actually quite shocking⁷ to me that they were so much better."

The researchers examined levels of two hormones⁹ in the rats – one that causes stress and another that counters it. All rats that took part in the training had higher levels of the hormone⁸ that reduces stress. The research suggests the increased relaxation¹⁰ levels could be linked to the enjoyment¹¹ of successfully completing a new skill.

The team also found that the rats that drove themselves showed higher levels of the stress-fighting hormone than those that simply rode in small cars controlled by humans.

Lambert said the most exciting result of the experiment for her was about the possible effect on humans. The research may open new areas of non-drug treatments for people suffering from mental health conditions.

"There's no cure for schizophrenia or depression and we need to catch up," she said. "And I think we need to look at different animal models and different types of tasks and really respect that behavior can change our neurochemistry."

Speaking to the British-based magazine New Scientist, Lambert said her team is planning to continue experiments to learn more about how the rats learned¹² to drive. The new research will also examine why some activities appear to reduce stress, and which areas of the brain are involved in the process.

As an example, Lambert said new driving tests could be created to test the effects of Parkinson's disease¹³ on motor skills and awareness¹⁴ of space. "If we use more realistic and challenging models, it may provide more meaningful data," she told New Scientist.

Words in This Story

button – n. something you press to control a piece of equipment

relax – v. to become happy and comfortable because nothing is worrying you

steer – v. to control the direction of a vehicle

treat – n. a piece of free food, drink, etc., provided¹⁵ to someone

flexible – adj. able to be easily changed

enrich⁵ – v. to improve the quality of something by adding something to it

hormone – n. one of several chemicals produced in the body that influence growth and development

stress – n. feelings or worry or nervousness caused by difficult situations or problems

task – n. a piece of work, especially something unpleasant or difficult