Temporal Contrast Enhancement in Thermosensation: A Framework for Understanding Paradoxical Heat Sensation

Abstract

AbstractParadoxical Heat Sensation (PHS) is the remarkable feeling of warmth or heat pain while the skin is cooling (Hämäläinen et al., 1982; Pavlicek & Jenkins, 1933). Despite its initial documentation over 100 years ago (Goldscheider, 1884), a unified explanation for this perplexing experience remains elusive, defying traditional models of thermosensation. Here, we apply contrast enhancement principles, known for their instrumental role in understanding visual illusions, to the domain of thermosensation. Contrast enhancement describes the amplification of two contrasting visual features (Hess et al., 1998), such as the enhanced perception of an edge between a light and dark bar. We extend this concept to thermosensation, which encompasses an enhancement of the difference between sequential warming and cooling of the skin and predict that this mechanism underlies the experience of PHS. Remarkably, thermal contrast, defined as the normalised difference between successive temporal warm and cold temperatures, predicts the occurrence of PHS. Our findings reveal compelling evidence supporting the role of thermal contrast in the generation of PHS, shedding light on its underlying mechanism and offering a framework for understanding broader encoding principles in thermosensation.HighlightsParadoxical Heat Sensation (PHS) is an illusion of heat during skin coolingWe propose thermal contrast enhancement as a unifying explanation for this paradoxThermal contrast predicted PHS prevalence in healthy individuals (N = 208)Our model explains previously unaccounted for psychophysical features of PHSIn BriefMitchell et al. demonstrate that contrast enhancement principles are applicable to thermosensory perception and provide a comprehensive framework for understanding paradoxical heat sensation, a previously enigmatic perceptual phenomenon.