Computers obey brain waves of paralyzed

Imagine you’re a mediocre bowler. Imagine you’ve just released the ball, and in those long seconds as it approaches the pins it wanders toward the gutter and you’re mentally telling it, “Get back! Get back there!

And now imagine that it does.

There might be an easier way to do this, if you’re willing to have surgery.

When surgeons at Washington University in St. Louis, in cooperation with Wolpaw, placed tiny electrodes on the surface of the brains of four people recently, they achieved accuracies of 74 percent to 100 percent with just three to 24 minutes of training.

Some researchers put electrodes into the brain. Donoghue’s Cyberkinetics system includes a chip about the size of a baby aspirin with 100 wire-like sensors, each thinner than a hair. The chip goes on the surface of the brain and the sensors extend about .04 inch below the surface.

Rather than monitor brain waves, the device intercepts a sample of the very signals that command arm movement, Donoghue said. So a patient doesn’t have to learn how to control his brain waves, he just has to imagine moving his arm. “At that point,” Donoghue said, “it works.”

That’s been the experience with the quadriplegic volunteer in Massachusetts, who showed he could move a cursor around a screen effectively, though less smoothly than healthy people can, Donoghue said. Cyberkinetics hopes to try its “BrainGate” system in four more patients this year and bring a product to market by 2007 or 2008.

Scientists who study implanted devices say scalp recordings like Wolpaw’s just couldn’t provide enough detailed information from the brain for elaborate control and natural movement of robotic arms or reanimated human limbs.

Researcher Andrew Schwartz at the University of Pittsburgh notes that his monkeys can move a cursor or robot arm in three dimensions, while Wolpaw’s subjects can so far operate a cursor only in two dimensions. Schwartz also questions how consistently people can stay “in the zone” of peak performance with scalp recordings.

Wolpaw, for his part, says implanted electrodes don’t pick up all the brain’s signals for movement. It’s like trying to play a symphony with only violins, he says. “You’re using the violins alone to control the output,” he said. “How well that will work remains to be seen.”

What’s more, he says, signals from implanted electrodes might be diminished over time by scar tissue, dying brain cells and slight displacements within the brain. As for staying in the zone, he said, that gets easier with practice. Right now, consistency is an issue with all the brain-signal approaches, he said.

He said he can’t think of any task that shouldn’t be achievable someday with scalp electrodes, in combination with some sophisticated software to handle the details. And while scalp electrodes haven’t yet shown they can do everything implanted ones can, he said, they’ve already come pretty close.

“We may not have the same batting average,” he said, but “we’re playing in the same league.”

Still in its infancy
I did not make Rookie of the Year.

“You’re a success, you’re just not a stellar success,” Wolpaw told me. “You’re at the lowest level we would call actual control.”

That is, my accuracy had climbed to around 65 percent. About 80 percent of people reach or surpass that level within 10 sessions. Frankly, it felt more like influence than control.

But my 12 sessions were just an introduction, and I’d probably get better if I stuck with it, he said.

That doesn’t necessarily mean I’d stumble across some magic visual image that would instantly transform me into a virtuoso. In fact, visual images are just training wheels, giving some guidance while the real learning happens.

What was really going on during the 2,592 times I shot at a target over a total of about six hours? My brain was learning through simple trial and error. Although my brain, Wolpaw said, was a bit slower on the uptake than most people’s.

Fine.

But the fact is, I was eventually able to make that red box sink fairly often without any need for imagery.

That may not sound like much. But in an area of brain science that’s still in its infancy, few people on Earth can say they’ve accomplished that.

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