彭蒙惠英语：Send in the Rescue Rats（在线收听）

Send in the Rescue Rats

By Emily Singer © 2004, New Scientist Magazine.

Reed Business Information Ltd. All rights reserved.

Distributed by Tribune Media Services.

Rats equipped with radios that transmit their brainwaves could soon help locate survivors buried in the wreckage of collapsed buildings

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Rats have an exquisitely sensitive sense of smell and can crawl just about anywhere. This combination makes them ideal candidates for sniffing out buried survivors. Of course, the animals have to be taught to home in on people, and then they must signal their position to rescuers on the surface. In a project funded by the Defense Advanced Research Projects Agency (DARPA), the Pentagon’s research arm, Linda and Ray Hermer-Vazquez of the University of Florida worked out a way to achieve this.

First, the researchers identified the neural signals rats generate when they have found a scent they are looking for. “When a dog is sniffing a bomb, he makes a unique movement that the handler recognizes,” says John Chapin, a State University of New York neuroscientist who is collaborating with Ray and Linda on the project. “Instead of the rat making a conditioned response, we pick up the response immediately from the brain.”

“There are two [types of] neural events that we believe are hallmarks of the ‘aha!’ moment for the rat,” says Linda. High-frequency activity occurs in one subset of neurons, and decreased activity is observed in two other areas, she says.

Reading the rat’s mine

Each rat has electrodes implanted in three areas of the brain: the olfactory cortex, where the brain processes odor signals; the motor cortex, where the brain plans its next move; and the reward center, which, when stimulated, gives the rat a pleasurable sensation. The electrodes are permanently implanted in the brain and can give accurate signals for up to nine months.