AI Insight
This study examined how the brain encodes variations in pain perception within and between individuals using EEG data from 161 participants who rated painful stimuli in sessions four weeks apart, with findings validated in an independent cohort of 111 participants. Researchers found that neural patterns associated with how pain perception fluctuates within the same person over time were robust and reproducible across different groups, while neural patterns linked to differences between individuals were not replicable across cohorts. This indicates that brain activity patterns tracking intra-individual pain variations are fundamentally more stable and reliable than those reflecting inter-individual differences.
Why it matters
These findings suggest that brain-based biomarkers for pain are better suited for monitoring pain changes within individual patients over time rather than comparing pain levels between different people. This has important implications for developing clinical tools to track treatment responses and disease progression in individual patients, and suggests that personalized, within-person approaches may be more effective for pain assessment and management than population-level comparisons.
Understand the Science
by Laura Tiemann, Felix S. Bott, Elisabeth S. May, Moritz M. Nickel, Vanessa D. Hohn, Cristina Gil Ávila, Nicolò Bruna, Paul Theo Zebhauser, Markus Ploner
The perception of pain varies both within and between individuals, even when sensory input remains constant. Understanding how the brain encodes these intra- and inter-individual variations is central to elucidating the neural mechanisms of pain and to developing reliable brain-based markers for clinical use. Yet, previous findings have been inconsistent, and their robustness across time and populations remains unclear. Here, we used electroencephalography (EEG) in 161 healthy participants to re-investigate the neural patterns explaining intra- and inter-individual variations in the perception of brief painful stimuli independent of stimulus intensity. Using Bayesian multivariate multi-model regression, we related pain ratings to canonical EEG responses. To directly assess robustness, the experiment was repeated after 4 weeks in the same participants and replicated in an independent cohort (n = 111). Neural patterns associated with inter-individual differences in pain perception were repeatable over time but not replicable across cohorts. In contrast, neural patterns underlying intra-individual fluctuations were robust both over time and across cohorts. These findings indicate that within-person and between-person variability in pain perception is encoded by distinct neural patterns that differ fundamentally in their robustness. Furthermore, they show that brain-based markers are particularly suited for tracking intra-individual fluctuations of pain, while being less sensitive to inter-individual differences. More broadly, they highlight the importance of within-person approaches for advancing both mechanistic models of pain and the development of clinically useful biomarkers.
Source: Neural encoding of pain is robust within but unstable between individuals