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 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% 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, Miguel Nicolelis, a neuroscientist at Duke. In the new treatment, animals whose brains were depleted of dopamine had tiny electrodes, the size of a fingernail, implanted on their spinal cords. Three seconds after a mild electrical stimulation began, they could move about normally.
The treatment was also effective when combined with L-dopa in further experiments; only two doses of L-dopa were needed to produce movement, compared with five doses when it was used by itself. Spinal cord stimulation represents a “big conceptual change” in how to treat Parkinson’s disease, Nicolelis said. Rather than looking at where things happen in the brain, the approach focuses on when things happen, as in the dynamic firing patterns of large circuits of neurons.
These circuits oscillate in harmony and underlie normal brain function. Parkinson’s patients have abnormal low-frequency oscillations in the brain regions controlling movement, Nicolelis said. Stimulation of the topmost layer of the spinal cord, which conveys touch sensations to the brain, may work by disrupting these abnormal oscillations, restoring normal firing patterns across multiple brain structures involved in the control of voluntary movements.
Sources: The Times Of India
Related articles by Zemanta
- What Causes Parkinson’s Disease? (oup.com)
- ‘Brain Pacemaker’ Not Without Risks (abcnews.go.com)
- University of Pennsylvania researchers find that the unexpected is a key to human learning (scienceblog.com)