New findings shed light on chronic Pain origins in the brain

In a groundbreaking study, researchers have made a significant breakthrough in understanding chronic pain by identifying a specific brain area linked to this condition. Utilising advanced machine learning tools and analyzing data collected over several months, the research team, which included scientists from the University of California, San Francisco, successfully pinpointed biomarkers associated with chronic pain disorders caused by stroke or amputation.

Published in the esteemed journal Nature Neuroscience, the study offers promising insights into how pain is represented within the brain and explores potential avenues for alleviating the suffering experienced by individuals with chronic pain. With chronic pain being a leading cause of disability worldwide, this research carries immense importance for improving the quality of life for those affected.

Unlike acute pain, which is typically a response to injury or illness, chronic pain persists over an extended period and is often resistant to conventional treatments. Neuropathic pain, specifically, results from damage to the nervous system itself. While it commonly arises from nerve injuries within the body, the individuals participating in this study exhibited pain originating from the brain. This unique form of pain poses a considerable challenge to effective treatment and can severely impact the daily lives of those afflicted.

By gaining a deeper understanding of how chronic pain is manifested in the brain, researchers hope to develop innovative strategies to modulate brain activity and provide much-needed relief to individuals suffering from this debilitating condition. The identification of specific biomarkers associated with chronic pain represents a significant step forward in unraveling the mysteries of this complex phenomenon and offers new possibilities for future therapeutic interventions.

“When you think about it, pain is one of the most fundamental experiences an organism can have,” said Prasad Shirvalkar, associate professor of anaesthesia and neurological surgery at the University of California, San Francisco, and lead author of this study.

“Despite this, there is still so much we don’t understand about how pain works,” said Shirvalkar.

In this study, the researchers looked directly at changes in brain activity in two regions where pain responses are thought to occur – the anterior cingulate cortex (ACC) and the orbitofrontal cortex (OFC) – as participants reported their current levels of chronic pain.

“Functional MRI studies show that the ACC and OFC regions of the brain light up during acute pain experiments. We were interested to see whether these regions also played a role in how the brain processes chronic pain,” said Shirvalkar.

“We were most interested in questions like how pain changes over time, and what brain signals might correspond to or predict high levels of chronic pain?” said Shirvalkar.

Four participants, three with post-stroke pain and one with phantom limb pain, were surgically implanted with electrodes targeting their ACC and OFC. Several times a day, each participant was asked to answer questions related to how they would rate the pain they were experiencing, including strength, type of pain, and how their level of pain was making them feel emotionally.

They would then initiate a brain recording by clicking a remote-control device, which provided a snapshot of the activity in the ACC and OFC at that exact moment.

Using machine learning analyses, the research team was able to use activity in the OFC to predict the participants’ chronic pain state.

In a separate study, the researchers looked at how the ACC and OFC responded to acute pain, and found that brain processes acute vs. chronic pain differently, though more studies were needed to establish that, they said.

The study said it represented an initial step towards uncovering the patterns of brain activity underlying our perception of pain. Identifying such a pain signature will enable the development of new therapies that can alter brain activity to relieve suffering due to chronic pain, it said. 

(With inputs from PTI)