Rats turned into remote-controlled 'robots'

WASHINGTON — Scientists for the first time have managed to remotely direct movements of rats by using implanted electrodes to control behavior — in effect transforming a living animal into a robot.

The technique, detailed yesterday in the journal Nature, has potentially important implications for activities ranging from land-mine detection to earthquake-victim recovery to spying to the emerging field of "neural prostheses" — using electronics to bridge nervous-system gaps caused by spinal injury, stroke or other physical infirmities.

"It's really just conditioning behavior," said physiologist John Chapin of the State University of New York (SUNY) Downstate Medical Center, noting that training animals to do human bidding is as old as teaching dogs to fetch. "But it's different in that you can do it all with remote control. In theory, you could guide the animal anywhere."

Researchers from SUNY and Drexel University implanted electrical probes in parts of the brain that affect what the animals sense and how they behave. They then trained the rats to respond to impulses sent through the implants.

Once trained, the animals could be controlled up to 550 yards by an operator with a laptop computer transmitting to a small backpack receiver worn by each rat.

In fact, after training a "roborat" for eight to 10 days in a figure-eight maze, researchers can steer it through any three-dimensional route. The rat can be induced to climb ladders, descend ramps, walk a pipe or navigate uneven terrain. The rat will even climb trees or wander a brightly lit room — alien behaviors for the animal.

"We developed a way to create seemingly complex behaviors in animals by generating cues and rewards," said SUNY's Sanjiv Talwar, the lead researcher. "The rats could almost understand what you wanted them to do."

Mary Beth Sweetland, vice president of People for the Ethical Treatment of Animals, an animal-rights group based in Norfolk, Va., was not impressed.

"Rats are not Tonka trucks with whiskers," she said. "This is just another way that people are showing how they really feel about rats."

Some scientists also acknowledged many people may find such remote brain control disturbing, but not so much because of its impact on rodents.

The technique almost certainly could work in other species, including humans, said Paul Glimcher, an expert at New York University on the neurobiology of making decisions.

"That is what is so disturbing about it," Glimcher said. "It is clearly a technique that if applied to humans would have huge legal, moral and ethical ramifications. That raises real questions about whether a technology of this type could be used to undermine the autonomy of an individual decision maker."

Until now, scientists have only been listening to the electrical signals generated by brain cells. They are able to decipher the brain's output and use it to activate machines.

Several laboratories have used brain-cell activity from rats and monkeys to control robotic arms, even when the device — connected through the Internet — is hundreds of miles away.

Last month, Brown University researchers successfully wired a monkey to a computer so that its mental activity could move a cursor.

With this latest accomplishment, scientists are talking back to brain cells.

To perform the experiment, scientists injected signals directly into sensory and learning areas of the brain. They wanted to learn how to create the feedback of touch and other sensations normally provided by a living limb.

In all, the scientists successfully wired five rats in a project funded by the Department of Defense.

Each animal had three sets of hair-thin wires implanted in its brain. One wire went to a part of the forebrain that generates a sensation as a reward to reinforce behavior. The other electrodes went to regions responsible for the rat's whiskers, used to navigate.

The electrodes, in turn, were connected to a wireless transmitter in a lightweight backpack powered by a 9-volt battery. The rat's backpack also contained a tiny video camera. Researchers are considering adding other sensors, such as a global-positioning-system unit to track the rat better.

The scientists steered the rats by activating the whisker centers, creating the sensation of a touch on one side or the other. Sending signals to the brain's reward center reinforced correct behavior.

"In some real sense, they have produced a computer bridle," Glimcher said.

"Instead of a whip and carrot, they use direct activation of the learning circuit in the brain itself, which is pretty cool."

"These guys are showing that there is a way to deliver the signal to the brain directly, and apparently the signal can be interpreted. This is a very important result," said Miguel Nicolelis at Duke University, who also works on brain-machine interfaces.

It may be most important as a harbinger of things to come, as brain researchers become more adept at manipulating the organ responsible for thought and behavior, several experts said.

"Long before we get to the real ethical problems posed by changing our genes, we will have to deal with the consequences of the revolution in neuroscience," said Arthur Caplan, director of the University of Pennsylvania Bioethics Center.

"This rat research is primitive stuff, but it is a shot across our bow that should alert us to the potential consequences."

Information from Knight Ridder Newspapers is included in this report.