The researchers concluded that such brain surface stimulation could be effective without requiring the complex brain stereotactic surgery necessary to place the deep-brain electrodes that are now used for such treatment.
In their experiments, the researchers implanted electrodes epidurally on the motor cortex in the animals and studied the effects of stimulation on movement initiation (akinesia) and slowed movement (bradykinesia) seen in Parkinson's disease. They found a significant reduction in symptoms after only a few minutes of stimulation, which lasted until shortly after stimulation was stopped.
Analyses of changes in brain electrical activity due to the stimulation revealed that it restored the normal activity in the striatum--the area known to become hyperactive in Parkinson's and the area that is targeted in deep-brain stimulation. Brain scans using positron emission tomography (PET) of the animals' brains also revealed that the stimulation increased activity in the motor cortex, which is known to suffer reduced activity in Parkinson's.
Studies of the animals' brain tissues showed no cell loss or inflammatory response in any area of the brain, including the stimulated region, reported the scientists.
They concluded that "motor cortex stimulation appears to be a potential alternative to deep-brain stimulationwith major advantages in terms of simplicity and safety of the procedure."