Algae and Light Help Injured Mice Walk Again

Scientists are working on unconventional methods for controlling neurons in the brain. In one such experiment, a mouse's behavior was controlled by shining a light directly on its brain! But this was no ordinary brain -the mouse had DNA from algae inserted into its neurons, which made them responsive to light. The crucial part of these experiments is making the new genes active in only certain types of neurons, depending on the outcome we are looking for. Stanford psychiatrist Karl Deisseroth and his team are experimenting with optogenetics to help victims of Parkinson's disease, starting with mice.

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)