Researchers have identified an area of the brain linked to chronic pain in a study that could lead the way for the discovery of new pain treatments.
This is the first time that scientists have been able to record pain-related data from inside the brains of individuals with chronic pain disorders caused by stroke or amputation – phantom limb pain.
The findings will help researchers understand more about how pain is represented by brain activity and ultimately enable them to modulate this activity to relieve chronic pain.
The study was funded by the US Government’s National Institute of Health and published in Nature Neuroscience,
Chronic pain is pain that carries on for longer than twelve weeks despite medication or treatment and is one of the most significant contributors to disability worldwide. The participants in this study suffered from neuropathic pain, a type of chronic pain caused by damage to the nervous system itself. It most commonly occurs due to injury to the nerves in our bodies, but for the individuals in this study, their pain is thought to originate from the brain itself. Current treatments for this type of pain are ineffective, meaning the condition can often become debilitating.
Traditionally chronic pain information is gathered from patient questionnaires about pain intensity and the emotional impact of living with the pain. However, this study looked directly at changes in brain activity in two regions where pain responses are thought to occur.
Four participants were implanted with chronic intracranial electrodes in the anterior cingulate cortex (ACC) and the orbitofrontal cortex (OFC). Pain-related data was collected multiple times a day over a period of months at the patients’ homes. The data were analysed using machine learning tools, a type of artificial intelligence (AI) which allows software applications to become more accurate at predicting outcomes without being programmed to do so.
The analysis allowed the researchers to identify an area of the brain associated with chronic pain as well as successfully predicted individual chronic pain severity by observing the brain activity. They were also able to identify biomarkers of chronic pain in individual patients based on objective measurements rather than patient’s self-reporting of pain.
Prasad Shirvalkar, an associate professor of anaesthesia and neurological surgery at the University of California and lead author of the study, said: ‘Pain is one of the most fundamental experiences an organism can have. Despite this, there is still so much we don’t understand about how pain works. We were most interested in how pain changes over time and what brain signals might correspond to or predict high levels of chronic pain?’
This study represents a first step towards developing novel methods for tracking and treating chronic pain. The researchers hope the preliminary findings could lead to effective, non-addictive pain treatments.
Mr Shirvalkar added: ‘By developing better tools to study and potentially affect pain responses in the brain, we hope to provide options to people living with chronic pain conditions.’