Previous research has found that pain-related impairments in working memory depend on emotional distress. However, the specific brain and psychological factors of emotional distress contributing to this relationship are not well understood.
This new study published in the journal Neuropsychologia sought to address the gap in research. It used publicly available brain imaging and self-report data from the Human Connectome Project (HCP). Brain imaging and self-reported data were used from 416 HCP participants to analyze the brain’s structural and functional connections. Researchers used structural equation modeling (SEM), a statistical technique for complex modeling relationships between multiple variables.
In the 228 participants who reported experiencing some level of pain in the seven days before the study, authors found that those who reported higher pain intensity were directly associated with worse working memory performance. This conclusion was made from the outcome of a common test, the n-back task.
In this test, participants are shown a series of letters and asked whether the letter they are seeing appeared on a screen previously. The more screens back in the sequence that participants are asked to recall, the more working memory is required.
Increased Activity in Frontal Cortex
Researchers also found that higher pain intensity was indirectly associated with working memory performance through increased activity in a particular region in the center of the frontal cortex called the ventromedial prefrontal cortex (vmPFC). This region of the brain is involved in pain, cognition, and distress. Researchers found that the relationship between everyday pain and vmPFC brain activity in this study is similar to prior research, which showed outcomes in patients with chronic pain.
“We found that healthy participants with even low levels of reported pain had different levels of activity in the vmPFC during the n-back task compared to healthy participants who didn’t report pain. Surprisingly, this pattern of activity was more similar to patients with chronic pain than healthy patients who are exposed to pain manipulations in a laboratory,” said researcher Joanna Witkin.
Previously, most research has focused on the relationship between chronic pain and cognition. However, researchers believed it was essential to learn how daily pain impacts the brain.
The researchers concluded, “This study highlights the real impact that pain can have on our ability to think even in healthy people, and points how this may come about in the brain.”