Mice that have had a stroke regain motor function after specific brain neurons are stimulated by light.

Using a technique called optogenetics, Michelle Cheng, Gary Steinberg and their colleagues at Stanford University in California studied mice that were genetically engineered to express a light-sensitive protein in a group of neurons in the brain's motor cortex.

The team induced a stroke on one side of this area and then activated the engineered neurons by switching on a small, implanted light probe. This stimulation increased blood flow and the levels of various growth factors in the opposite, uninjured cortex. Moreover, these animals gained more weight and walked faster and farther than unstimulated stroke mice.

Further study of the mechanisms of this recovery could lead to new drug targets or therapy techniques for stroke, the authors say.

Proc. Natl Acad. Sci. USA http://doi.org/vbj (2014)