Scientist Build a 'Brain' From Rat Cells

ByABC News

Oct. 27, 2004 -- -- Using 25,000 neurons from the brain of a rat, scientists at the University of Florida in Gainesville have created a living "brain" that can fly a simulated high performance aircraft.

The "brain in a dish" is the brainchild of Thomas DeMarse, professor of biomedical engineering at the university, and it is a remarkable bit of work in that it allows researchers to study how a brain functions on a cellular level. That could lead to all sorts of improvements in the treatment of various mental illnesses, because it could become a valuable tool in the drive to understand one of the most complex and amazing devices in the universe, the human brain.

But beyond all that, it really can fly that F-22 fighter jet. Or perhaps more accurately, it can keep the aircraft on course in all kinds of weather, acting as an autopilot as it corrects any change in the plane's course.

And the brain in the dish learns how to do that in an amazingly short period of time.

"Usually, within 10 to 15 minutes, it's pretty much flying the plane," DeMarse says.

The research is another step in one of the hottest areas of science these days. Computer wizards and biologists and neurologists around the world are trying to fabricate artificial brains, or neural networks, that can function on a human scale, taking over such tasks as piloting rescue aircraft into enemy territory.

There have been various reports of partial success. A team of Russian scientists claimed recently to have created an artificial brain that functions on a human level, although that claim has been met with broad skepticism in the west.

Most claims are far more modest, although it is clear that a marriage between neurology, or the study of the human brain, and high speed computers is leading into territory that sounds more like science fiction than fact. Some experts have warned that incredibly smart machines might someday leave the rest of us in the dust, usurping our self-appointed role as the most important creatures on the planet, if not the universe.

Hugo deGaris, who spearheaded Japan's program to develop the famous robot kitty, and who is now heading a similar project at Utah State University, believes that this century may bring "massively intelligent machines with intellectual capacities many times greater than those of human beings."

DeGaris said in a recent essay that we are not prepared to have our role taken over by machines that may eventually decide we are unnecessary and "should be exterminated."

Scary stuff, but that's getting way ahead of our story. DeMarse's rat neurons aren't about to take over the universe. In fact, they can't even remember how to fly that aircraft for more than about 15 minutes, so they're no threat.

Yet remarkable they truly are. They are bridging an enormous gap in the effort to study how brains function. It can't be done on the cellular level while the neurons are still in the rat because they are far too small to be seen inside the skull by even the most advanced imaging techniques.

But take them out and put them in a petri dish, and the live neurons can be observed checking out their neighboring neurons as they begin the process of building a neural network, or, as DeMarse puts it, "a living brain."

The dish is on top of an array of 60 electrodes that allows the scientists to record the neural activity. And from that they can train the neurons to control the aircraft through a flight simulator.

"Here's the trick to it," DeMarse says. "We have these recordings coming out of the dish, and that allows us to get the behavior [of the neurons] into the simulated plane."

But how do the neurons learn how to fly the thing? That's done by electrical pulses into the dish through one of the electrodes. That in effect tells the neurons when they are doing the right thing to keep the plane on course. High frequency, or rapid pulses, stimulate the neurons and enhance the connections between them.

Simply put, by stimulating the neurons the researchers tell them they're on the right track, so they continue to adjust the plane's elevator to keep it from plunging toward the ground during a downdraft, for example. When the plane levels off, the simulator reduces the frequency of the pulses, and the neurons back off from that control surface, allowing the plane to remain on course.

After just a few minutes of that kind of training, the "brain" takes over completely, sending signals to the plane's control surfaces, and using feedback from the simulator to know just which signals to send.

And then, after about 15 minutes, it's all over. The neurons can't remember how to fly the plane anymore, so the next time the experiment is run, the neurons have to be taught all over again.

It all sounds very complex, but DeMarse says it's actually a very simple experiment, and he hopes to change that. The experiment currently uses only two electrodes to send and receive signals, and the brain of a mammal uses many avenues, or sensors, to do what it has to do to survive.

So the "brain in a dish" is actually a very simplified brain, even for a rat. But if that's the case, how come we can't teach a rat how to fly an aircraft?

Maybe we could, DeMarse says, if we knew how. But there would still be a bit of a problem.

"Their visual system isn't that good," he says. "The rat wouldn't be able to see past the cockpit."

DeMarse doesn't think the purely biological model he's working with is likely to ever pose a threat to human dominance. Even the relatively simple "brain in a dish" that can fly a simulator is difficult to maintain.

But still, the neural network he is exploring, along with many other scientists, is setting the stage for the creation of hybrid computers that are based largely on biological systems and could potentially dwarf the most powerful supercomputers today. And if they get too smart, as Utah State's deGaris notes, we might want to be sure they learn to love us.

Lee Dye's column appears weekly on A former science writer for the "Los Angeles Times," he now lives in Juneau, Alaska.

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