Effects of temperature and water content on wet perception during the static touch of moist paper

Abstract

[Background] Wet perception plays an essential role in behavioral thermoregulation. It has been suggested that mechanical and thermal stimuli affect wet perception; however, the mechanism remains unclear. This study aimed to clarify the effects of water content and temperature on the wet perception of moist papers. [Methods] Twenty-seven healthy volunteers (14 males and 13 females, age 25 ± 5 years) participated in this study, which comprised two experimental trials. In Experiment 1, participants placed the index finger on 2 x 2 cm filter paper of 6 different water content (0.00, 3.75, 7.50, 11.25, 15.00, or 18.75 μg/cm 2 ) for 15 s, of which temperature was controlled at 30ºC with Peltier apparatus. During the last 5 s of the stimulation period, participants were asked to report if they had wet perception or not. Each water content was presented five times, and the percentage rate of wet perception was calculated. In Experiment 2, participants placed the index finger on 2 x 2 cm filter paper of water content of 18.75 μg/cm 2 for 15 s, of which temperature was controlled at either 20, 25, 30, 35, or 40°C with Peltier apparatus. During the last 5 s of the stimulation period, participants were asked to report the intensity of their thermal and wet sensations with a visual analog scale. Each temperature was presented five times. [Results] Experiment 1: The percentage rates of wet perception of 3.75, 7.50, 11.25, 15.00, and 18.75 μg/cm 2 were significantly higher than that of 0.00 μg/cm 2 ( p < 0.05). The percentage rates of wet perception of 11.25, 15.00, and 18.75 μg/cm 2 were significantly greater than those of 3.75 μg/cm 2 ( p < 0.01) and 7.5 μg/cm 2 ( p < 0.005). Experiment 2: Thermal sensation of the stimuli of 25, 30, 35, and 40ºC was greater than that of the 20ºC stimulus ( p < 0.001). Wet perception of the stimulus of 20ºC was greater than that of 25, 30, 35, and 40ºC. Wet perception of the stimulus of 25ºC was higher than those of 30, 35, and 40ºC ( p < 0.05). [Discussion and Conclusions] The percentage rate of wet perception increased with the water content of the paper. Thus, participants could discriminate such small differences in the water content. The wet perception was augmented by stimulus temperature lower than 30ºC, while stimulus temperature above 30ºC did not show a clear relationship with the intensity of wet perception. The cold sensation may play an important role in modulating wet perception. Research Fellow of Japan Society for the Promotion of Science and Japan Society for the Promotion of Science KAKENHI Grant-in-Aid for Scientific Research A 19H01128. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.