Paralyzed, Moving a Robot With Their Minds

"The two people in this study, a 58-year-old woman, and a 66-year-old man, are quadriplegic, unable to use their limbs as a result of strokes years ago.

Each had a tiny sensor about the size of a baby aspirin injected just below the skull, in an area of the motor cortex known to be active when people move their arms or hands. They learned to move a robotic arm, mounted at shoulder height on a dolly next to them, by watching the researchers move the arm and imagining they were actually controlling it.

The sensor — a chip of silicon with 96 pinprick electrodes connecting to a patch of neurons — transmitted those neurons’ firing patterns from this imaginary movement to a computer, through a wire. The computer recorded the patterns, then translated them into an electronic command: Move left, now down, now right."