Many experts had thought the cure was to stimulate certain kinds of cells within the subthalamic nucleus, which coordinates motion. But when they tried that, it had no effect whatsoever. Then two of Deisseroth’s grad students began experimenting with a dark-horse idea. They stimulated neurons near the surface of the brain that send signals into the subthalamic nucleus — a much harder approach because it meant working at one remove. It was as if, instead of using scissors yourself, you had to guide someone else’s hands to make the cuts.
Their idea worked. The mice walked. In their paper, published in April 2009, they wrote that the “effects were not subtle; indeed, in nearly every case these severely parkinsonian animals were restored to behavior indistinguishable from normal.”
Other experiments on rhesus monkeys show promise. The team is now designing ways to make optogenetics safe and effective for humans. Link
(image credit: Justin Wood)