Wednesday, November 30, 2005

Placebo Cyborgs | Expecting results may help medicine work better

CTV reports today that sometimes cyborgs are better cyborgs when their own brains are doing the feedback, according to research by Dr. Fabrizio Benedetti (Department of Neuroscience, University of Turin Medical School in Italy): "Parkinson's patients moved much better when they were told that doctors had turned on a pacemaker-like implant in their brains, which blocks tremors, than when it was turned on covertly," explains this CTV article.

In their article "Placebo-responsive Parkinson patients show decreased activity in single neurons of subthalamic nucleus" (Nature Neuroscience 7.6 [June 2004]: 587-588) Benedetti et al. describe using electrode implants to measure activity of neurons in the subthalamic nucleus (a target in therapy for Parkinson's Disease). The placebo was an injection of saline solution and the suggestion of a motor improvement.

Dr. Benedetti spoke on "The Biological Basis of an Imaginary Treatment" at on February 15, 2005 at the London School of Economics. The precis: "An imaginary treatment is a simulation of a real treatment, showing that the context around the patient may affect the therapeutic outcome. This occurs through the release of endogenous substances in the brain which modify the activity of neurons. These new neurobiological acquisitions have both clinical and ethical implications."

Benedetti and others recently published "Expectation enhances autonomic responses to stimulation of the human subthalamic limbic region" (Brain, Behavior, and Immunity 19.6 [November 2005]: 500-509). Microelectrodes inserted into the subthalamic regions provided the means for "microstimulation" of the STN, which has known autonomic effects (such as an increase in heart rate) and emotional effects (such as feelings of well being and pleasure) in the human. But telling the patient when this was happening apparently had a significant impact on the response: "Most interesting, the overt and covert stimulations of this area produced very different outcomes. Sometimes the open–hidden difference was as large as 50%, both for heart rate and sympathetic responses."


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