Abstract:

Objective The perception mechanism and quantitative characterization of human physiological comfort stimulated by fabric was always one of the difficult problems in the field of textile and garment, but there was still a lack of systematic research on the connection structure between fabric materials and human perception through neural electrophysiological response. Therefore, this research is purposed to study the potential components of somatosensory brain region evoked by fabric tactile were analyzed in detail, so as to improve the neurophysiological mechanism of perceptual science, and provide theoretical reference and research approaches for dynamic, in-situ and quantified comfort characterization of textile materials.

Method The tactile properties of cold and warm sensations of textiles were tested by KES-FB7 system, and event-related potentials technology was employed, which is a non-invasive and high time resolution brain monitoring technology based on electrophysiological reaction. In a relatively quiet experimental environment, the EEG of 20 young volunteers under tactile stimuli from fabrics with different cold and warm sensations was monitored and analyzed by using event-related potentials technology. The contact comfort of the fabric was verified through a subjective questionnaire survey.

Results Based on the results of physical tests and subjective questionnaire surveys, the contact comfort perception results of the fabric's cold and warm sensations obtained by the two methods were highly consistent (Pearson correlation coefficient r=0.98, p=0.00<0.05). Among them, the contact cold sensation (Q_max) value of the silk fabric sample (4^#) was the largest, and the Q_max value of the double-sided plush fabric sample (7^#) was the smallest, respectively, determining them as representative cold-sensing fabric and representative warm-sensing fabric. According to the analysis of the brain electrical activity map, it was found that the response intensity of the brain at 300 ms after receiving the fabric tactile stimulation was the highest. Therefore, the P300 potential was established as the characteristic potential for perceiving the contact cold and warm sensations of the fabric for analysis. The statistical analysis of the amplitude and latency of the characteristic potential results showed that the contralateral brain region and the middle brain region presented positive potential activation responses, while the ipsilateral brain region presented negative potential activation responses. The P300 potential amplitude evoked by the representative cold-sensing fabric was the largest, and the latency was the shortest. The P300 potential amplitude evoked by the representative warm-sensing fabric was the smallest, and the latency was the longest. Moreover, there were significant differences between the two. The correlation analysis results showed that the P300 potential amplitude was highly linearly correlated with the fabric's Q_max value, but in terms of latency, as the Q_max value increased, the latencies of both sides of the brain region shortened irregularly at a fluctuating speed, while the latency of the middle brain region remained relatively stable and shortened at a single exponential decay degree.

Conclusion Because of the asymmetry of the neural transmission pathways for tactile information, the activation responses of the two hemispheres of the brain were opposite. Moreover, as the Q_max value of the fabric increased, the intensity of the stimulation to the human body also increased, and the activation intensity of the brain regions responsible for somatosensory function also increased linearly, manifested as a linear increase in the P300 potential amplitudes. The latency of the P300 potential was usually considered as a time index providing the duration of perception processing. Some studies had also shown that the latency of P300 in the CZ brain region was related to overall cognitive function, showing that as the degree of cold sensation stimulation by the fabric increased, the reaction speed of the human brain increased, resulting in a shortened latency. However, because of the perceptual aftereffect caused by neuronal adaptive fatigue, the human brain reaction exhibited certain delays, lags, and adaptability, leading to a buffering effect on the speed of the P300 potential latency shortening. In short, when the Q_max value began to increase, the brain reacted quickly to the stimulus; but when the Q_max value continued to increase, the reaction time of the brain to tactile stimuli still shortened, but the rate of shortening slowed down.

Key words: fabric comfort, cold and warm sensation, event-related potential, brain perception, somatosensory brain region