Brain zap helps spine-damaged rats walk

Applying electrical pulses deep in the brain improves speed and endurance

Editor’s Note: Science News intern Tanya Lewis is attending the neuroscience meeting in New Orleans on a travel award from the Society for Neuroscience.

NEW ORLEANS – Stimulating the brains of rats with spinal cord injury improves their ability to walk, researchers reported October 15 at the annual meeting of the Society for Neuroscience. The findings may suggest ways to treat spinal injuries in humans.

Known as deep brain stimulation, the approach has already been shown to be an effective treatment for easing the movement symptoms of Parkinson’s disease. It involves surgically implanting a kind of pacemaker for the brain that delivers small electrical pulses to hard-to-reach brain areas. For the rats, the targeted area was a region of the midbrain that, when activated, sends commands to the spinal cord that enable walking.

Rats in the study, by Brian Noga, Ian Hentall and colleagues at the University of Miami’s Miller School of Medicine, were given mild, moderate or severe bruises that severed some nerves in the spinal cord and left others intact. Such damage is common in human spinal cord injuries, of which about 60 percent are this “incomplete” variety. Over a 10-week period, researchers monitored the injured rats as they walked on a treadmill.

While receiving deep brain stimulation, rats showed a noticeable improvement in treadmill walking speed and endurance. The biggest improvements were among rats that could fully support themselves, but some unsupported rats did exhibit stepping movements. The results suggest, counter to what has long been thought, that walking ability can be enhanced even without a fully intact spinal cord, Noga reported at the meeting.

Scientists are still a long way from applying the treatment in humans. But unlike some other experimental treatments for spinal cord injury, deep brain stimulation has already cleared the hurdle of FDA approval for use in movement disorders.

Deep brain stimulation is not the only form of electrical stimulation that could help restore movement after a spinal cord injury. Other research involves directly zapping the spinal cord (SN: 6/30/12, p. 5) or stimulating nerves that control muscles in the arms and legs.