When Jan Scheuermann grasped a chocolate bar and raised it to her mouth last year, it was a neuroscience breakthrough. Scheuermann, who has lost the movement of her limbs due to a degenerative spinal condition, was piloting a mechanical arm connected to her brain, using her thoughts to replicate natural motion.
It was also a triumph for Andrew Schwartz, a neurophysiologist at the University of Pittsburgh, who’s spent three dec-ades mapping the connections between the brain and the body. Until the 1980s, scientists believed the brain interacted with limbs in a fairly rote, mechanical way: Certain neurons lit up when corresponding muscles moved. Schwartz was part of a Johns Hopkins University research team that found the brain was actually expressing an intentional behavior, like turning a doorknob, that he could read in the neuron’s electrical signals. “When you watch someone dancing … there’s a sort of beautiful coordination and precision and athleticism incorporated in the movement,” he says. “Those are the kinds of things we could find in this cortical activity.”