In his Philadelphia lab, neurobiologist John Chapin has connected a robotic arm to the brain of a rat, creating a direct link between mind and machine.
Chapin and his colleagues at the MCP Hahnemann School of Medicine began by teaching rats to press a lever that moved a robotic arm holding a tiny cup of sweetened water. Electrodes implanted in the rats' brains recorded which neurons they used and converted the signals into an electrical impulse that could directly control the motorized arm. Soon the rats no longer needed to press on the bar to get their sugary treat; they just had to think about it.
A much-refined version of this system could begin aiding paralyzed humans in about a decade, Chapin says. He foresees placing about 500 mini-electrodes in the brain, along with miniaturized detectors that would pick up, amplify, and transmit neural signals. Those signals would allow the patient to move either a robotic arm or a powered exoskeleton built around the real arm. Eventually it might be possible to route nerve impulses from the brain to another set of electrodes that would stimulate muscles in the paralyzed limb, restoring the lost mobility.
"The hardest thing to do will be to produce gait and posture, since it is such a complex process, but I think it could be done," Chapin says.