According to a report published in Current Biology, reduced pain perception while being distracted from pain is an everyday example of how cognitive processes can interfere with pain perception. Researchers from the University Medical Center, Hamburg-Eppendorf, Germany, using high-resolution spinal fMRI (functional magnetic resonance imaging) as people experienced painful levels of heat, demonstrated that mental distractions actually inhibit the response to incoming pain signals at the earliest stage of central pain processing. Endogenous opioids, which are naturally produced by the brain are important in the relief of pain and this study demonstrates this process.
This research involved two components. Participants (n=20, healthy males) were first asked to complete either a hard or an easy memory task, both requiring them to remember letters, while they simultaneously applied a painful level of heat to their arms. When distracted by the harder of the two memory tasks, participants perceived less pain. In addition, their less painful experience was reflected by lower activity in the spinal cord as observed by fMRI scans.
For the second component of the study, the researchers then gave participants either a drug called naloxone, which blocks the effects of opioids, or a simple saline infusion as a control. The pain-relieving effects of distraction dropped by 40 percent during the application of the opioid antagonist compared to saline, evidence that endogenous opioids play an essential role.
The authors point out that “our findings also have clinical implications, because they demonstrate that cognitive factors, which are well-known predictors of pain perception and chronification, act not only on a psychological level but are indeed able to modulate pain transmission in the spinal cord. Although an opioidergic mechanism behind cognition related pain modulation has been hypothesized previously, this is the first study to show a reduction of behavioral analgesia during cognitive demand by naloxone treatment.”
These findings demonstrate how well mental processes can alter the experience of pain, and additional research will detail the contribution of this pain modulatory system and its impact on the spinal cord especially to reveal its predictive value for pain perception in
different pain syndromes.