14 DAY TRIAL // The placebo effect has been documented on numerous instances. It is most obvious in the field of medicine, where patients told that they were given drugs for their pain or diseases seem to get better even though the pill itself contained only sugar or flour. Such an instance was recently documented using advanced observations technology, in people being treated for burns. Scientists say that the action of the effect at this point defies explanation, NewScientist reports.
The dorsal horn of the spinal cord, a formation located more towards the back of the spine and made out of gray matter, was the target for the new investigation. The scientists used functional Magnetic Resonance Imaging (fMRI) to determine how the spinal-cord neural activity that is usually linked to pain modified after a placebo treatment was applied. FMRI usually cannot be used for such studies, as it is best suited for analyzing the cortex. In addition the dorsal horns are surrounded by cerebrospinal fluid, which makes observations even more difficult.
In the experiments, the team applied a painful source of heat on volunteers' arms, and then looked at how activity in the dorsal horns modified. They then divided participants in two groups, and applied cream on their members' hands. One group received an actual painkiller in the cream, while those in the placebo group were only told that the cream contained active ingredients, when in fact it did not. The experts were puzzled to notice that the pain-related activity in the spinal cord had disappeared even in the placebo group.
“This type of mechanism has been envisioned for over 40 years for placebo analgesia. This study provides the most direct test of this mechanism to date,” University of Florida in Gainesville (UF) neuroscientist Donald Price, who was not a part of the new research, says. The study was conducted by a team of experts from the University Medical Center Hamburg-Eppendorf, in Germany, led by neuroscientist Falk Eippert.
The scientists say that the brain releases endogenous opioids when dealing with pain, and that it releases them in equally large quantities in the case of the actual painkiller and the placebo treatment. These opioids work like opiates, and temper the activity inflicted in the spine cord by the application of a painful stimulus. Eippert says that the knowledge could be used to create various new treatments for chronic pain and other conditions that would take advantage of the power of belief.