At the annual meeting of the Society for Neuroscience, researchers from the University of Miami’s Miller School of Medicine reported that stimulating the brains of rats suffering from spinal cord injury improves their ability to walk. While this kind of brain stimulation has proven to be an effective treatment for easing the movement symptoms of Parkinson’s disease, it could pave the way for a new treatment for spinal injuries. Brain stimulation counters the long-held thought that walking ability cannot be enhanced without a fully intact spinal cord.
About 60 percent of human spinal cord injuries are “incomplete,” with only some nerves severed and other left intact. Researchers at the Miller School of Medicine gave rats mild, moderate or severe bruises mimicked similar human injuries and monitored the rats over a 10-week period as they walked on a treadmill.
Researchers stimulated the brain region that releases serotonin throughout the spinal cord from highly branched nerve fibers, and this region also releases peptides that stimulate growth. A kind of pacemaker is implanted in the brain, which delivers small electrical pulses to brain areas. When signals are sent to the midbrain, this commands the parts of the spinal cord that enable walking.
When the rats received deep brain stimulation, there was a noticeable improvement in both speed and endurance while walking on the treadmill. Rats that could fully support themselves experienced the most improvement, while unsupported rats also showed improvements in stepping movements.
However, this form of treatment poses challenges. Brain regions that need to be stimulated are deep in the hindbrain and could create many risks for neurosurgery. Dr. Ian Hentall, who led the pilot research, also tested midbrain areas that have been safely stimulated in patients to reduce severe pain.
Deep brain stimulation uses proven technology that can have a low rate of adverse effects, unlike drug side effects, and it can be immediately stopped. This form of therapy can immediately relieve major symptoms, and for acute spinal cord trauma, the brief stimulation might give lasting restoration, so implants do not have to be permanent. Much more research is needed before using this as a treatment in humans, but the research shows promising results that could help change spinal cord injuries in the future.