An implantable device may help people with neurological disorders regain their lives

"Can I show you something?" the researcher asks. Before anyone responds, his fingers quickly tap away at the computer. On his screen, a video frame paused on a lab rat appears.

"It's been paralyzed for weeks," explains Kendall H. Lee, M.D., Ph.D., a neurosurgeon at Mayo Clinic in Minnesota. He clicks the play button, and the rat's right leg jolts to life. He plays more clips. In one, a leg slowly rises and falls. In another, both legs alternate movement, mimicking a swimmer's kick.

"It's not just twitch," he says. "We're controlling this wirelessly."