Time course of burn to repeated applications of capsaicin

Human subjects rated the burn of 100 ppm capsaicin applied to the tongue via filter paper and replaced every minute. Capsaicin was presented at a constant concentration for 10 min, followed by 10 min of blank stimuli; this sequence was then repeated once. Both sensitization and desensitization were seen. A dynamic model composed of a level detector and change detector predicted the results and also previous data. Thus, the model provides a parsimonious description of responses to constant and intermittent capsaicin stimulation.