VOA标准英语2013--Electric Fish Offer Insight Into Human Central Nervous System

 

Electric Fish Offer Insight Into Human Central Nervous System

Electric fish live mostly in fresh water in tropical rivers and are found primarily in only two parts of the world.

There are two main groups, one in South America, the Gymnotiform, and that’s about 200 species that are known," said Rudiger Krahe, associate biology professor at Canada’s McGill University. "And then there is a second group in Africa, the Mormyri fish, and there are also about 200 species.”  

These two groups evolved independently, yet share the same ability to generate and sense weak electric waves. Their electric fields can be recorded with simple devices that pick up the signals in the water. 

“We can observe electrically, observe the activity of these fish continuously because they produce these signals non-stop, day and night," Krahe said. "And so we can monitor what they do, what their signals look like, how they modulate¹ them  in different context such as communication and then we can play them back artificially to them in experiments.”

While humans never developed this electric sense, our nervous system processes signals from our environment in much the same way as these fish do.

“How information is transmitted, how different aspects of the sensory² information are extracted, that’s extremely similar to what happens in the auditory systems, so, in our hearing, and also, in many ways, what happens in vision,” Krahe said.   

Fish don’t have brains nearly as complicated as humans, but many of the structures and pathways are quite similar. That link offers a new approach to understanding human physiology³.   

“How we extract sensory information, how we use that to guide our behavior, how our nervous system accomplishes that and of course we do experiments with fish that we cannot do with humans," Krahe said. "And we’re trying to learn general principles of nervous system action, basically, and how behavior is controlled. ”

This research could be applied⁴ in studies on the impact of serotonin, a hormone⁵ in the central nervous system believed to influence mood and depression.

1 modulate   

v.调整，调节(音的强弱)；变调

参考例句：

• Please modulate the sound on the TV.请调节一下电视的音量。
• This system could modulate the voice signal effectively.这个系统可以对语音信号进行有效的调制。

2 sensory   

adj.知觉的，感觉的，知觉器官的

参考例句：

• Human powers of sensory discrimination are limited.人类感官分辨能力有限。
• The sensory system may undergo long-term adaptation in alien environments.感觉系统对陌生的环境可能经过长时期才能适应。

3 physiology   

n.生理学，生理机能

参考例句：

• He bought a book about physiology.他买了一本生理学方面的书。
• He was awarded the Nobel Prize for achievements in physiology.他因生理学方面的建树而被授予诺贝尔奖。

4 applied   

adj.应用的；v.应用，适用

参考例句：

• She plans to take a course in applied linguistics.她打算学习应用语言学课程。
• This cream is best applied to the face at night.这种乳霜最好晚上擦脸用。

5 hormone   

n.荷尔蒙，激素，内分泌

参考例句：

• Hormone implants are used as growth boosters.激素植入物被用作生长辅助剂。
• This hormone interacts closely with other hormones in the body.这种荷尔蒙与体內其他荷尔蒙紧密地相互作用。