And what it means for robots.
Computers are smart enough to beat humans at chess, Go, and Jeopardy!, but when it comes to basic hand movements, robots can still only master rudimentary tasks.
Robots aren't able to bake a cake or mow the lawn, for example, which means "we don't fully understand how the brain does it," said neuroscientist Jörn Diedrichsen, who's working to untangle how the human brain controls hand movement. "We don't even have a robot that can control its hand as well as a two-year-old."
Once we figure out how the brain controls fine motor skills, we'll be able to build more skilled, capable robots—and prosthetics that make us more powerful.
Diedrichsen is working on that now. The scientist, who just joined Western University after leaving University College London, is focused on helping stroke patients and others regain fine motor control, although more capable robots and improved prostheses will be another outcome.
"Our body is a complete engineering nightmare"
Western University, in London, Ontario, is investing heavily in cognitive neuroscience research. Diedrichsen was lured there partly because of its state-of-the-art imaging facilities: The campus is home to three fMRI machines, used to measure and map brain activity. Using the scanner, he can chart people's neural activity as they perform various tasks and movements with their hands.
Diedrichsen needs as much imaging technology as he can get, given the magnitude of the mystery around what he's studying. For example, his research has found that electrical stimulation to the brain can help motor training—in a double-blinded study published in 2014, subjects who were zapped with weak currents performed 20 percent better than those who were not, and the effect lasted for a month—but the reasons why still aren't clear.
Further research on so-called "electric doping" could potentially help stroke patients and people who have suffered a spinal cord injury recover lost function. It could also improve prosthetics by informing our understanding of how the brain and body connect.
Scientists have already built bionic limbs that patients can control with their minds. But they still aren't very good. "Our body is a complete engineering nightmare. Our muscles fatigue. Our tendons are sloppy and hard to control. We have good sensors in our fingertips, but they're not reliable," Diedrichsen said. "The brain makes really amazing things out of a quite poorly engineered physical plan."
If we could engineer something better—and harness a fuller understanding of the brain—imagine what we could do.