How the Brain Enhances Perception of Pain from Multiple Sources

When experiencing pain from multiple sources—such as a minor injury combined with heat exposure—the sensation can feel significantly more intense than the sum of individual stimuli. This phenomenon raises the question: does the brain simply add these signals, or does it actively amplify the overall pain experience?

Pain perception is known to be highly subjective, influenced not only by the physical intensity of stimuli but also by cognitive factors like attention, expectations, and instructions on how to perceive pain. However, understanding how the brain integrates different pain signals into a unified, sometimes amplified, experience was not fully understood.

A recent study published in tions of the Royal Society B provided new insights into this process. Led by Dr. Kong Yazhuo from the Chinese Academy of Sciences, the research explored how perceptual instructions—such as focusing on the overall pain rather than individual sensations—affect pain perception and the underlying neural mechanisms.

In their experiments, participants were subjected to heat, pressure, and electrical stimuli, either alone (single-modal) or combined (bimodal). The researchers used functional magnetic resonance imaging (fMRI) to measure brain activity and collected participants' pain ratings. Notably, when instructed to perceive the combined stimuli as a single, integrated pain sensation, participants reported higher pain levels compared to when no such instructions were given.

The findings revealed that the enhancement in pain perception was linked to activity in the precuneus, a brain region situated between the two cerebral hemispheres, just behind the posterior cingulate cortex. The BOLD response in the precuneus positively correlated with the degree of perceived pain integration, suggesting its key role in this process.

Interestingly, this integration effect depended on top-down cognitive influences rather than the mere addition of stimuli. It was absent in trials with non-painful stimuli, indicating that perception is modulated by higher brain functions rather than direct sensory inputs alone.

The study’s results imply that the brain actively constructs an intensified pain experience through the neural processing in the precuneus, especially when individuals are directed to perceive the stimuli as a unified, integrated pain. This understanding could influence clinical approaches, emphasizing the importance of perceptual context in managing complex or masked pain syndromes.

As Dr. Kong noted, recognizing how cognitive and neural mechanisms influence pain could pave the way for targeted interventions. Addressing the perceptual and neural aspects of pain might improve treatment outcomes for patients suffering from chronic or multifaceted pain conditions.

For more detailed information, see the original study published in the Proceedings of the Royal Society B: DOI: 10.1098/rspb.2025.1229.

source: https://medicalxpress.com/news/2025-06-brain-amplifies-perception-pain-multiple.html