Brain region responsible for the ‘placebo effect’ identified

By using functional magnetic resonance brain imaging (fMRI) technology, researchers from the  Rehabilitation Institute of Chicago (RIC) and Northwestern University have identified the part of the human brain responsible for the pain-relief phenomenon known as the placebo effect.

As reported earlier this week by Psych Central and the Pain News Network, Dr. Marwan Baliki, a research scientist at RIC as well as an assistant professor at Northwestern University Feinberg School of Medicine, and his colleagues identified a region in the front part of the brain (the mid frontal gyrus) responsible for providing real relief when patients take phony treatments.

The researchers conducted two separate trials involving 95 patients suffering from chronic pain due to osteoarthritis. In the first, they found that the mid frontal gyrus was better connected with other parts of the brain in approximately half of the patients, and were more likely to respond to the placebo effect. In the second, the initial findings were validated with 95% certainty.

“Given the enormous societal toll of chronic pain, being able to predict placebo responders in a chronic pain population could both help the design of personalized medicine and enhance the success of clinical trials,” Dr. Baliki said in a press release. His team’s findings were published Thursday in the open-access, peer-reviewed scientific journal PLOS Biology.

Findings could mark the end of trial-and-error pain treatments

Identifying the region of the brain responsible for the pain-killing placebo effect could result in the development of personalized treatment options for the millions of people in the US suffering from chronic pain, the researchers explained. It could also lead to more precise clinical trials for pain medications by disqualifying potential subjects that respond strongly to placebos.

As part of their work, Dr. Baliki and his colleagues used fMRI and a standard clinical trial design to find a brain-based neurological marker that could predict pain-relieving affects in patients who experienced chronic knee pain due to osteoarthritis. In fact, more than half of the participants had reported significant pain relief, according to the study authors and if future studies can expand on these results, they could provide a brain-based predictive option for individual patients.

That, the researchers said, would decrease the exposure of patients to ineffective therapies while also decreasing the time and magnitude of pain and opioid use. In short, it would prevent doctors from having to use a trial-and-error approach to treatments which might expose patients to drugs that could be ineffective and potentially dangerous.

“The new technology will allow physicians to see what part of the brain is activated during an individual’s pain and choose the specific drug to target this spot,” said co-author Dr. Vania Apkarian, a physiology professor at Northwestern. “It also will provide more evidence-based measurements. Physicians will be able to measure how the patient’s pain region is affected by the drug.”


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