This is wild. Chasing the elusive dream of curing paralysis, a team of scientists used stem cells and optogenetics to circumvent the central motor system of lab mice whose nerves had been cut. This enabled them to blast individual motor neurons with a laser, triggering movement in the legs of the mice.
Okay, so it's a little bit complicated, if you're not familiar with how optogenetics work (and honestly, why would you be?). The cutting-edge technique enables neuroscientists to modify specific neurons so that they're light sensitive. Shining light on the neuron then makes it fire, telling the brain to move a muscle or stop feeling pain.
In the case of the paralyzed mice, researchers modified the animals' stem cells so they'd produce a light-sensitive protein. The stem cells were then programmed to turn into motor neurons and engrafted onto the sciatic nerves of the mice. All the reserachers had to do then was shine a light on the light sensitive motor neurons and—boom—the mice weren't paralyzed any more. To be specific, the neurons fired and caused the once-paralyzed leg muscles to move. "We were surprised at how well this worked," says Linda Greensmith of University College London who led the team.
There's obviously a lot of work to be done before we start implanting stem cells and lasers into human legs, but this is an encouraging start. At the very least, it will help researchers better understand crippling neurological conditions like epilepsy. It's also a perfect entry in the annals of mad science. More here.