Sometimes just pretending to give a drug can alleviate the symptoms of Parkinson's disease, as long as the patient believes that the treatment is effective. Such placebo treatment works when it causes a part of the brain that is overactive as a result of the disease to return to a more normal level of activity, reports a paper in the June issue of Nature Neuroscience.
For several days, Fabrizio Benedetti and colleagues gave Parkinson's patients injections of drugs that temporarily relieved symptoms such as muscle stiffness and tremors. Then, the researchers gave the patients a placebo injection (a harmless salt solution containing no medication) without revealing the change. Before this placebo injection, the scientists surgically implanted metal wires into the brain to measure electrical signals emanating from single brain cells in a region called the subthalamic nucleus, which is hyperactive in Parkinson's patients. After the patients received the sham medication, these brain cells became less active and their arm muscles relaxed, allowing them to move more easily. The clinical improvement in individual patients was correlated with the changes in brain activity.
These findings are the first report of placebo responses in single neurons, and may help scientists to understand how people's mental states can influence their bodies.
Fabrizio Benedetti (University of Turin Medical School, Italy
Also available online.
(C) Nature Neuroscience press release.
Message posted by: Trevor M. D'Souza