Mind Over Machine

When a monkey has learned this skill, it’s ready for the third and final challenge: reaching plus grabbing. When the monkey moves the cursor to the dot, it now has to squeeze the joystick. Sensors measure how hard the monkey squeezes, and the computer screen displays the force as an expanding disc on the screen. By watching the disc expand, the monkey learns how to apply different amounts of force in order to get its reward. "She has to squeeze very precisely," says Nicolelis.


No one knew if a monkey could meet this challenge. Clearly, the electrode arrays could recognize commands to move the arm back and forth. But what if squeezing was controlled by neurons too far away from the electrodes to be monitored? Nicolelis put his faith in the orchestral nature of neurons—and he wasn’t disappointed. The system could predict how hard the monkey was squeezing as well as it could predict where it was moving the arm. "The predictions," he says with pride, "are unbelievably good."




Much of the money that funds Nicolelis’s research comes from DARPA, which in 2003 ratcheted up its long-standing interest in brain-related research to a new level by launching the Brain-Machine Interface Program (BMI) with an initial grant of $24 million divided among six different labs. "Imagine how useful and important it could be for a war fighter to use only the power of his thoughts to do things at great distances," says Tony Tether, the director of DARPA.


DARPA is famous for funding futuristic technology of all sorts, from the precursor to the Internet to the ill-fated terrorist futures market, which was attacked by Congress last summer. And according to former BMI program director Alan Rudolph, DARPA is well aware that there’s no guarantee that the brain-machine interface research will ever make it onto the battlefield. "There’s plenty of risk," he says. "If there wasn’t a lot of risk, we wouldn’t be involved."


In addition to the Duke research, DARPA’s funding is helping other scientists pursue the linkage of brain and machine. At the University of Michigan, for example, it’s supporting research that may eventually let humans control a more classic free-standing robot with their thoughts. The robot in question, known as RHex, can scurry around on six legs like a mechanical cockroach. Researchers are investigating how to teach rats to control the movement of RHex by pressing levers that steer the robot left and right. Then, in a process similar to the one employed at Duke, scientists will decode the brain patterns the rats use to press the different levers, and enable the rat to guide RHex by thought alone. Humans could someday use the same system to guide robots into collapsed buildings or across rough terrain on distant planets—or, DARPA hopes, into battle.


Not all of DARPA’s research is limited to manipulating machines. The brain does more than just move arms and legs—it also sends out complex commands that control muscles in the throat, tongue and mouth, creating speech. It’s conceivable that a computer could learn to recognize those commands before they leave the brain and then translate them into words. "You could imagine thinking about talking and having it projected into a room 2,000 miles away," says Craig Henriquez. "I don’t see that that will be a problem. It’s very, very possible."


But Henriquez and other neuroengineers do see one particularly enormous roadblock in the way of DARPA’s goal. According to Rudolph, it would be unethical to implant
electrodes in the heads of healthy soldiers. He’s betting that future technology will be able to read brain signals without actually being inside the brain. Today the most common way to attempt this is with electroencephalography (EEG), in which electrodes are placed on the scalp. But EEG has a serious drawback: It can only pick up a blurry, weak signal compared to what electrodes nestled in the brain can record. People can learn to control a computer by altering their EEG patterns, but it takes months of training to type just a few letters a minute. That’s not the sort of bandwidth you want for operating an arm. "To the best of our knowledge, that doesn’t look very promising at the moment," Henriquez says.