External magnetic fields or spine implants could provide alternatives to invasive brain surgery.
http://www.nature.com/news/2009/0903....2009.173.html

The symptoms of Parkinson's disease could one day be relieved by indirect electrical stimulation of the brain, via the spinal cord or even through the surface of the skull, according to two studies on rodents.

Miguel Nicolelis, a neuroscientist at Duke University in Durham, North Carolina, and his colleagues have now shown that, in animal models of Parkinson's disease, the DBS effect can be achieved by stimulating fibres in the spinal cord1.

The team's finding "opens the door for trials of less-invasive spinal-cord stimulation in other animal models of Parkinson's disease and in parkinsonian patients", says Bart Nuttin, a neurosurgeon at the Catholic University of Leuven in Belgium who has performed many DBS operations.

Meanwhile, at Stanford University in California, neuroscientist Karl Deisseroth and his colleagues have found that the neurons activated by DBS might lie not at the site of the electrode, but much closer to the surface of the brain2.

This means that doctors might be able to reach the neurons by using non-surgical techniques such as transcranial magnetic stimulation, where magnetic fields induce weak electric currents in the brain. Both studies are published in this week's Science.