The brains behind the pilot rat

Thomas DeMarse got a rat's brain to control an F-22 flight simulator. Amazing? Just part of the job, he says.

By RON MATUS
Published December 30, 2004

[Photo: Ray Carson, University of Florida] University of Florida researcher Thomas DeMarse holds a glass dish containing a "brain" -- a living network of 25,000 rat brain cells connected to an array of 60 electrodes that can interact with a computer. "I do this stuff every day," he said. "So for me it's like, ehhhh."

GAINESVILLE - After University of Florida scientist Thomas DeMarse used a rat's brain cells to control a flight simulator, newspapers around the world couldn't help themselves. They dubbed the feat "Frankensteinian," and spun headlines like, "Rat brain flies jet."

DeMarse claims to have paid little attention.

"I do this stuff every day," says the biomedical engineering professor. "So for me it's like, ehhhh."

Don't let the scientific cool fool you.

DeMarse, 37, and his peers around the planet know their work is pushing the limits of science. If they can better understand how the human brain works, they can make contributions to everything from disease research and drug development to building better computers.

Scientists know, for example, that the brain cells of Alzheimer's patients are disrupted by protein deposits, but they don't know exactly how they are disrupted.

"You want to know how the brain does what it does, how it computes," DeMarse says in his lab, between sips of office-brewed Starbucks. "The more you know about that, the more you can apply that information to real-world problems ... especially diseases."

For brain scientists, these are heady times.

Researchers are taking on the brain from different angles, sharing their findings across a wide array of disciplines.

In October, a Massachusetts company announced the results of an experiment in which a quadriplegic in a wheelchair was able to play a computer game, thanks to sensors linking his brain to a computer. Earlier this month, New York scientists reported the development of a system that allows people, wearing an electrode-laden cap, to move a computer cursor simply by thinking about it.

Everyday applications may be years away. But they no longer are the stuff of science fiction.

DeMarse's project is both less and more than what the headlines suggest.

There is no wire-rigged brain, pulsing in a bowl.

Instead, there are about 25,000 rat neurons - or brain cells - thriving in a glass tray the size of an eyeglass lens. Considering the human brain has billions of neurons, 25,000 doesn't add up to much. Picture grains of sand sprinkled in water.

The neurons are nourished weekly, and almost immediately begin to extend weblike strands to connect with each other.

"You're sending out connections to your neighbors, looking for a neuron to either talk to or a neuron that you should be talking to," Demarse says.

Soon, a network forms.

The bottom of the tray is outfitted with 60 electrodes, which are connected to a common desktop computer and a flight simulator for an F-22 fighter jet.

A mere cargo plane wouldn't do for DeMarse's brain.

His visions of the future include dish-bound brains flying tiny, agile, unmanned planes. So "we wanted something that would be difficult," he says.

The computer sends the neurons data about flight conditions - whether the nose of the plane is up or down, and drifting left or right - much as the rat's eyes and ears would have fed information to its brain, DeMarse says.

At first, the plane crashed, repeatedly. But over time, the neurons responded.

Eventually, they learned to keep the plane flying straight, even in hurricane-force winds.

"The network modifies itself," DeMarse says.

DeMarse prefers to say the neurons "adapted" rather than "learned," much like a plant moves toward light.

Either way, they worked together and changed.

In recent years, other scientists have conducted similar experiments.

At Georgia Tech, researchers used 2,000 rat brain cells to create what they called a hybrid robot, or Hybrot, part digital computer and part living brain. A researcher at Duke University monitored the brain signals of a monkey as it moved, then used those signals to operate a robotic arm.

Scientists say such research could lead to better understanding of and, someday, cures for neural disorders such as epilepsy. Artificial brains could be used to fly real planes instead of simulators, and perform dangerous jobs such as search-and-rescue missions.

DeMarse sees a spinoff toward more powerful computers.

"We recognize objects all the time, and we do it much better than a computer," he says. "By looking at this processing in living networks, we can learn something about how those networks perform those tasks."

Along the way, we might learn something about ourselves, too.

"How memory works ... that's what keeps me up at night," DeMarse says. "It's really a fundamental basis of who we are."

DeMarse's experiment spawned stories on CNN and Discovery Channel and writeups in Britain, Canada and Australia.

Some journalists were skeptical. A South Carolina reporter made a few extra phone calls after getting a UF press release to "make sure we weren't getting our network cable yanked a little bit."

But the brain checked out.

"Snicker, snicker, you say," the article continued. "But when have you actually seen the pilot whose intercom voice says, "Today we're cruising at 35,000 feet?"'

Times researcher Kitty Bennett contributed to this report. Ron Matus can be reached at matus@sptimes.com or 727 893-8873.

[Last modified December 30, 2004, 00:39:11]