Science Send in the Roborats Radio-controlled rodents could go places that
St. Bernards can't. But that's not why they're important BY MICHAEL
Ed Gabel for TIME
Monday, May. 13, 2002
In one sense, the news last week that scientists have created a "roborat"
represents an ingenious technical breakthrough. Engineers have tried for
years--without success--to build robots smart enough to cross even a railroad
track. Now, by combining off-the-shelf technology with a creature whose
maneuvering skills have been honed by millions of years of evolution, physiologists
at the State University of New York Downstate Medical Center in Brooklyn
have created remotely piloted rodents that navigate complex terrain at
the will of controllers who are more than 500 yards away. Wearing tiny
backpacks equipped with radio transmitters and miniature TV cameras, the
rats could someday be sent into a collapsed building to find survivors,
say the scientists, or into a minefield to sniff out danger or off on a
But look a little deeper, and the accomplishment is both less and more
than meets the eye. It's less in part because the technology involved
is so simple. Trainers have known for centuries that you can teach
animals to perform all sorts of behaviors with a system of rewards
or punishments. Neurophysiologists have known for decades that instead
of an external reward like food, you can send electric impulses
directly into the brain's pleasure center.
As they reported last week in Nature, Sanjiv Talwar and his colleagues
did just that, tickling the rats' brains via radio transmitter when the
rodents moved in a direction the researchers wanted. But although Talwar's
team got the rats to do things they ordinarily wouldn't--climb trees, go
out in bright light, ignore the scents of food and females--it took a controller
at the helm to make this happen.
So although the rats may sound like cyborgs, they are really just rodents
that follow instructions. And although they fit into tiny spaces and are
more or less expendable, they are less useful in many ways than bloodhounds
or bomb-sniffing dogs--or even primitive robots, which will roll mindlessly
into fires, under water or into the glow of a nuclear-power-plant meltdown.
What's truly novel about this project is the way the rat controllers
issue their instructions. By tapping a keyboard, they send signals via
radio waves to electrodes implanted in the animal's brain: a mild jolt
to neurons that sense the right whiskers means "turn right"; a zap to the
left-whisker neurons means "go left." The surprise was how easy this was
to do. Neurophysiologists have long dreamed of building artificial limbs
with tactile feedback that would be sufficiently sensitive to tell a user
when a hand is grasping a barbell tightly enough to keep it from falling
or a baby chick loosely enough to keep from crushing it.
That's what Talwar and his group were trying to understand. "We
wanted to determine how well rats understand incoming signals," he explains.
"When we stimulated a region of the whiskers, they 'felt' a touch." Someday,
says Mandayam Srinivasan, director of the M.I.T. Touch Lab, who helped
show two years ago that monkeys could control robots by thought alone,
"you could build a neural chip for paralyzed people, similar to a cochlear
implant for deaf people, that uses brain signals to control prostheses."
That's far beyond what either he or Talwar can do today, and so
they will keep working with lab animals--not to enslave them, as animal-rights
activists may fear, but to understand how their brains issue and respond
to signals. The idea of rescue or reconnaissance rats may continue to evolve
as well. Ultimately, says Talwar, the animals themselves might become sensors.
By implanting electrodes that record their neural activity, scientists
could see what a rat sees, merely by reading its mind.
Reported by Andrea Dorfman/New York
How to Wire Up a Rodent
To steer a roborat by remote control, scientists rely on classic behavioral
conditioning. First they implant electrodes in clumps of rat-brain cells
that govern whisker sensation and pleasure. When human controllers want
the rat to turn left, they beam a signal that triggers a mild electric
shock to the left-whisker cells. If the rat responds by turning left, it's
rewarded with stimulation of the pleasure cells. A right turn is signaled
by a pulse to the right-whisker cells. No signal means the rat should go
Source: Sanjiv Talwar, State
University of New York Downstate Medical Center