BROOKLYN, N.Y. - Rats guided by electrical impulses could one day act as living robots, capable of searching for survivors in a disaster or helping to clear landmines, researchers say.

Rats directed to environments they would normally avoid

The scientists were able to train rats with electrical probes implanted in their brains to run through pipes, climb up piles of rubble and jump from ledges in response to remote control signals.

In the study, five rats were fitted with electrodes in their brains and in the sensory centres in their left and right whiskers to give them directional cues.

Backpacks provided a power supply, and a laptop computer sent signals to steer the rats. In the experiment, the laptop signals were received from up to 500 metres away.

When a rat responded correctly to the directions, the researchers stimulated the reward centre in its brain to reinforce the positive behaviour.

The rats were trained to respond to the signals in a maze and then they ventured through an environment similar to an obstacle course.

John Chapin, a professor of physiology and pharmacology at the State University of New York in Brooklyn, and his colleagues found that stimulating the brain's reward centre prompted the rats to move forward.

The forward stimulation also worked when the rats were instructed to climb steps.

"We were also able to guide rats in systematically exploring large, collapsed piles of concrete rubble and to direct them through environments that they would normally avoid, such as brightly lit, open arenas," the researchers wrote in Thursday's issue of the journal Nature.

The study adds a remote-control dimension to 50 years of research into stimulating the reward centre in rats' brains.

But it also raises ethical concerns about turning animals into intelligent robots.