By electrically stimulating the spinal cords of rodents, scientists have reversed some of the worst symptoms of Parkinson’s disease.

As long as a mild current flows up their spines and into their brains, the animals regain the ability to scamper around their cages, as if they were normal.

The therapy, described in Friday’s issue of the journal Science, is a potential alternative to direct stimulation, which requires risky and invasive surgery to implant electrodes deep in the brain, researchers said. Only 30 percent of severely impaired Parkinson’s patients qualify for the operation.

Spinal cord stimulation would be less invasive and inherently safer, and it would reduce the amount of drugs needed to treat the disease, said the report’s lead author, Dr. Miguel A. L. Nicolelis, a neuroscientist at Duke. Dr. Nicolelis added that the procedure was now being tested on monkeys, and “if it succeeds, human clinical trials could begin in the next few years.”