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A group of scientists describe today in Nature their success at harnessing the ultimate instrument of remote control: the brain. Miguel Nicolelis of Duke University and his colleagues wired the brains of owl monkeys to mechanical arms such that the animals' thoughts controlled the robots' actions. Going one step further, they demonstrated that these thought signals could travel over the Internet and manipulate a robotic arm sitting 600 miles away in co-author Mandayam Srinivasan's laboratory at the Massachusetts Institute of Technology. "It was as if the monkey had a 600-mile-long virtual arm," Srinivasan said. The hope is that such work might lead to prosthetic limbs that are as easy to use as the ones they replace.
As a first step in this experiment, the researchers implanted as many as 96 electrodes into multiple regions of the cortex in the monkeys. (In one animal, the electrodes remained implanted for two years.) The electrodes allowed them to record the activity of large groups of individual neurons as the animals moved their hands and reached for food. Feeding this output into a computer, they found patterns, which they then used to construct a mathematical model capable of predicting the animal's hand trajectories in real time. Having completed this translation--neural output into predicted movement--they were ready to test how well the message traveled from monkey to machine. As it turned out, the animals were able to control the movements of the robot arm in three dimensions to reach for a piece of food.
"The reliability of this system and the long-term viability of the electrodes lead us to believe that this paradigm could eventually be used to help paralyzed people restore some motor function," Nicolelis comments. "This system also offers a new paradigm to study basic questions of how the brain encodes information. For example, now that we've used brain signals to control an artificial arm, we can progress to experiments in which we change the properties of the arm or provide visual or tactile feedback to the animal, and explore how the brain adapts to it." In fact, Nicolelis and his colleagues plan to soon begin "closed-loop" experiments involving just this sort of feedback.
