from New Scientist
01 May 02
"Robo-rat" controlled by brain electrodes
The researchers responsible for the "Robo Rat" claim their work will give neuroscientists a better understanding of how mammals learn to navigate. They say it will help pinpoint biochemical changes in the brain, and which brain regions are involved in processing different behaviours. They even suggest that such rats could be used to help clear minefields.
But beyond this, lead researcher Sanjiv Talwar of the State University of New York in New York City is uncertain what benefits will emerge from the experiments. "It's difficult to predict what other studies this could be useful for right now," he told New Scientist. "There's going to have to be a wide debate to see whether this is acceptable or not."
The idea of placing living creatures under direct human command is certainly raising concerns over the animals' welfare. "It's appalling, and yet another example of how the human species instrumentalises other species," says Gill Langley of the Dr Hadwen Trust based in Hitchin, Hertfordshire, which funds alternatives to animal-based research.
Brain electrodesAnimal experiments such as drug trials are usually justified using the utilitarian argument. For a procedure to be acceptable, any suffering caused to an animal is supposed to be outweighed by an obvious benefit to people.
"There are some ethical issues here which I can't deny," Talwar says. But he points out that the experiments stuck to guidelines laid down by the US National Institutes of Health, and he insists that the animal cannot be dubbed a "remote-controlled rat". The rat was not forced to do anything, he says, as the technique works by stimulating the reward centre of its brain.
The researchers implanted one of the electrodes into the medial forebrain bundle (MFB), the part of the brain responsible for sensing reward. They placed the other two in parts of the somatosensory cortical area that receive stimulation from the left and right whiskers. Finally, a radio receiver tucked inside a rat-sized backpack was plugged into an interface in the rat's skull.
The rats were trained to learn that they would be rewarded with continuous zaps to the MFB when they moved forwards, or when they turned according to an appropriate stimulation of the left or right whisker.
Carrot and stickTalwar likens the control over the rat to the way a donkey can be steered by a carrot on a stick. Though driven by a desire to be rewarded, the donkey remains in control of its movements. Using the same principle, the rat can be trained to do things it would not normally do, such as walking into brightly lit open spaces or jumping off a ledge.
But Gary Francione, an expert in animal welfare law at Rutgers University School of Law, says: "The animal is no longer functioning as an animal," as the rat is operating under someone's control.
And the issue goes beyond whether or not the stimulations are compelling or rewarding the rat to act. "There's got to be a level of discomfort in implanting these electrodes," he says, which may be difficult to justify.
Talwar says the animals probably could not be persuaded to risk their lives in any way. Even so, he admits he cannot rule out coercion completely. For instance, the rats were never trained to jump off a ledge, but would do when commanded to go forward.
In this case the stimulation appeared to act like a prod rather than a reward. Previous research has shown that if rats are stimulated electrically in this reward centre every time they press a lever, they may continue doing so until they die.
Fast forwardTalwar has so far wired up five rats. He suggests that other electrodes could be added to give additional commands, like faster, or up and down. In theory, the technique should work with any animal that has an MFB, including most mammals and birds, although it's likely that higher animals could learn to ignore the commands.
Talwar suggests wired animals would be ideal for search and rescue operations, as they could be directed through rubble to look for survivors and would be easier to navigate than mechanical robots.
But Langley is concerned that other scientists will repeat the experiments on other animals, despite the ethical issues this raises. "The US Federal Animal Welfare Act doesn't cover rodents or birds," she points out, so researchers would not need a licence or ethical approval.
Journal reference: Nature (vol 417, p 37)