Chen Chao-Chen, Rainville Pierre, Bushnell Catherine M
Centre de Recherche en Sciences Neurologiques, et Faculté de Médecine Dentaire, Université de Montréal,Montréal, Queébec, H3C 3J7Canada.
Pain. 1996 Nov;68(1):33-43. doi: 10.1016/S0304-3959(96)03180-6.
The present study evaluated the ability of humans to discriminate temperature decreases in the noxious and innocuous cold range. Two groups of five subjects detected changes in cold stimuli applied to the maxillary face. For five subjects, adapting temperatures of 22 degrees, 16 degrees, 6 degrees and 0 degrees C were used, and thresholds for detecting temperature decreases were determined using an adaptive psychophysical paradigm. Visual analogue scale (VAS) ratings of cold and pain sensation were also recorded at 5-min intervals throughout each session. A second group of five subjects performed a similar detection task, but in this case using classical psychophysical techniques (method of constant stimuli) and adapting temperatures of 22 degrees, 16 degrees, 10 degrees and 6 degrees C. These subjects described the quality of the detected change in sensation, in addition to rating overall cold and pain sensation throughout the session. Detection thresholds were 0.27 degrees, 0.48 degrees, 4.8 degrees, 8.0 degrees and >10.0 degrees C for baselines of 22 degrees, 16 degrees, 10 degrees, 6 degrees and 0 degrees C, respectively, indicating that discrimination was better in the innocuous cool (22 degrees and 16 degrees C) than in the noxious and near-noxious cold (10-0 degrees C) range (P < 0.05). Tonic adapting temperatures of 22 degrees and 16 degrees C were always rated as cool but not painful, whereas adapting temperatures of 10 degrees and 6 degrees were sometimes and 0 degrees C usually rated as painful. Phasic temperature decreases from 22 degrees and 16 degrees C always produced cooling sensations, whereas decreases from baselines of 10 degrees and 6 degrees C produced primarily sensations of painful and non-painful prickle. These data suggest that different afferent channels mediate cool and noxious cold perception and add support to the hypothesis that noxious cold sensation is mediated by subdermal nociceptors.
本研究评估了人类辨别有害和无害冷觉范围内温度降低的能力。两组各五名受试者检测施加于上颌面部的冷刺激变化。对于五名受试者，采用22℃、16℃、6℃和0℃的适应温度，并使用自适应心理物理学范式确定检测温度降低的阈值。在每个实验过程中，还每隔5分钟记录一次冷觉和痛觉的视觉模拟量表（VAS）评分。另一组五名受试者执行类似的检测任务，但在这种情况下使用经典心理物理学技术（恒定刺激法），适应温度为22℃、16℃、10℃和6℃。这些受试者除了在整个实验过程中对总体冷觉和痛觉进行评分外，还描述了所检测到的感觉变化的性质。对于22℃、16℃、10℃、6℃和0℃的基线，检测阈值分别为0.27℃、0.48℃、4.8℃、8.0℃和>10.0℃，这表明在无害凉爽（22℃和16℃）范围内的辨别能力优于有害和接近有害冷觉（10 - 0℃）范围（P < 0.05）。22℃和16℃的持续适应温度总是被评为凉爽但不疼痛，而10℃和6℃的适应温度有时被评为疼痛，0℃的适应温度通常被评为疼痛。从22℃和16℃的阶段性温度降低总是产生凉爽感觉，而从10℃和6℃基线的降低主要产生疼痛和非疼痛刺痛的感觉。这些数据表明，不同的传入通道介导凉爽和有害冷觉感知，并为有害冷觉由皮下伤害感受器介导的假说提供了支持。
