STANFORD, Calif. - Researchers at Stanford University were able to use light to induce normal patterns of muscle contraction, in a study involving bioengineered mice whose nerve-cell surfaces are coated with special light-sensitive proteins.
The new approach allows scientists to more accurately reproduce muscle firing order, making it a valuable research tool. The investigators, from Stanford's Schools of Medicine and of Engineering, also believe this technique could someday spawn practical applications, from restoring movement to limbs paralyzed by stroke or spinal-cord or brain injury to countering spasticity caused by cerebral palsy.
The study, to be published online Sept. 26 in Nature Medicine, employed a technology known as optogenetics, which involves the insertion of a specialized gene derived from algae into the genomes of experimental animals. This gene encodes a light-sensitive protein that situates itself on nerve-cell surfaces. Particular wavelengths of light can trigger nerve activity in animals endowed with these proteins, modifying nerve cells' firing patterns at the experimenters' will.
"Our group's focus is on restoring optimal movement for people with physical disabilities," said one of the study's two senior authors, Scott Delp, PhD, a professor of bioengineering and the Clark Professor in the School of Engineering. "With optical stimulation, we were able to reproduce the natural firing order of motor-nerve fibers - an important step forward."
Optogenetics was invented at Stanford by the study's other senior author, Karl Deisseroth, MD, PhD, associate professor of bioengineering and of psychiatry and behavioral science, who has used optogenetics in many experiments to conduct research on the central nervous system of freely moving animals. "This marks the first time the technique has been applied to the mammalian peripheral nervous system," Deisseroth said.
The peripheral nervous
|Contact: Bruce Goldman|
Stanford University Medical Center