PAIN ADAPTATION PHENOTYPES MODULATE CROSS-TRIAL CONTEXTUAL INFLUENCES ON TEMPORAL CONTRAST EFFECTS

Pain perception is influenced by temporal context, where identical stimuli can produce dramatically different experiences depending on preceding events. Temporal contrast enhancement paradigms, including offset analgesia (OA) and onset hyperalgesia (OH), provide controlled frameworks for studying these contextual effects within single trials, yet little is known about how context operates across multiple trials or how individual differences shape these processes. We present preliminary analyses of behavioral data from 78 healthy adults (Alter, 2020) who completed thermal pain tasks with four trial types: hold trials at constant temperatures and contrast trials with transient temperature changes designed to elicit OA or OH effects. We examined how previous trial experience influenced current trial pain responses and identified individual differences in adaptation patterns. Participants were classified based on pain trajectory slopes across sessions: sensitizers (n=14) showed increasing pain over time, habituators (n=30) showed decreasing pain, and a no-trend group (n=34) showed stable responses. Initial correlation analyses revealed that previous trial maximum pain is associated with current OH magnitude while previous trial minimum pain is associated with current OA magnitude. Critically, these cross-trial effects differed between adaptation groups. Sensitizers showed significant correlations for both OH-preceding maximum and OA-preceding minimum relationships, while habituators showed only the OH-preceding maximum correlation. These preliminary findings suggest that individual differences in pain adaptation fundamentally alter how temporal context shapes pain perception across trials. Future work will implement Bayesian integration models to formalize how evolving pain expectations differentially update across sensitizer and habituation phenotypes.