Scientists put moth on wheels and let the robotic times roll

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Times Staff Writer

Harnessing the electrical impulses of sight, scientists have built a robot guided by the brain and eyes of a moth.

As the moth tracks the world around it, an electrode in its tiny brain captures faint electrical impulses that a computer translates into action.

The moth, immobilized inside a plastic tube, was mounted on a 6-inch-tall wheeled robot. When the moth moved its eyes to the right, the robot turned in that direction.


The research, presented at the Society for Neuroscience’s annual meeting in San Diego this week, marked the latest advance by scientists who are trying to perfect the link between brain and machine.

The technology might one day help people who are paralyzed or have lost their limbs regain the ability to move. Scientists have developed experimental devices that allow those patients to move cursors on a screen or crude robotic hands using only their thoughts.

The technology might also lead to development of machines that can see and smell the world just as living things do, although scientists cautioned such an advance is a long way off.

While the “robo-moth’s” abilities are limited, the contraption also hinted at the possibilities of using the vast computing power inside even the smallest brains.

The moth’s vision has evolved over millions of years to accurately guide the insect as it dodges predators or seeks mates.

Although the moth brain is the size of a grain of rice, the insect’s ability to detect motion is “amazing -- beyond anything we could build,” said senior author Charles M. Higgins, an associate professor of electrical and computer engineering at the University of Arizona.


Higgins and other robotic researchers also have been working to exploit the eyesight of ordinary house flies and dragonflies. Higgins chose the tobacco hornworm moth for the latest experiment in part because the University of Arizona maintains a colony for research purposes.

“When you’re doing research, it helps that you don’t have to catch your insects,” he said.

The moth, which survives about a week in nature, is regarded as a pest because its larvae devour tobacco and tomato crops. With its 4-inch wingspan, the moth is often mistaken for a hummingbird.

In the experiment, researchers attached an electrode to a single neuron in the area of the moth’s brain responsible for keeping its vision steady during flight. The neuron transmitted electrical signals to an amplifier at the robot’s base, which was assembled from an inexpensive off-the-shelf kit.

Using a mathematical formula, a computer translated the signals into action, making the robot move.

To make the moth shift its gaze, researchers placed the robo-moth on a circular platform surrounded by a 14-inch-high revolving wall painted with vertical stripes. As the wall rotated clockwise, the moth’s eyes tracked the stripes. When the striped wall moved in the opposite direction, so did the moth’s eyes.

The longest transmission detected from the moth’s brain lasted 88 seconds, said coauthor Timothy Melano, a graduate student who worked on the project.


Higgins said a robot hooked into the moth’s sophisticated olfactory system might one day be used to detect bombs. After all, he said, “if it blows up, all you’ve lost is a moth.”

But many hurdles remain in the way of such a device.

Although the moth can direct the robot to turn left or right, it cannot make the robot move forward or backward. Signal detection also needs improvement, Higgins said.

To use a robo-moth as a bomb-sniffing device, researchers would have to get the insect to go where it was needed. At this point, researchers have no way of detecting or directing the insect’s intentions.

“We have taken baby steps,” Higgins said.