Greenspan Joel D, Roy Elizabeth A, Caldwell Patricia A, Farooq Naila S
Department of Oral and Craniofacial Biological Sciences, University of Maryland Dental School, Baltimore, MD 21201, USA.
Somatosens Mot Res. 2003;20(1):19-26. doi: 10.1080/0899022031000083807.
The thermosensory system was evaluated psychophysically in 12 healthy volunteers, spanning the full range of tolerable temperatures. Subjects provided ratings of (1) perceived thermal intensity, (2) perceived pleasantness or unpleasantness, and (3) perceived pain intensity after placing either one hand or foot in a temperature controlled water bath. Of particular interest were the interrelationships among the three perceptual measures, and differences between heat and cold. The relationship between perceived intensity and (un)pleasantness was different for hot vs cold stimuli. Specifically, for a given perceived thermal intensity, cold stimuli were rated as less pleasant or more unpleasant than hot stimuli. Similarly, for a given pain intensity, cold stimuli were rated as more unpleasant than hot stimuli. As warm temperatures increased and as cold temperatures decreased, stimuli were perceived as being unpleasant before they were perceived as being painful. The difference in transition temperatures for unpleasantness vs pain for heat averaged 1.4 degrees C, while the same difference for cold averaged 5.6 degrees C. Thus, there was a fourfold difference in the range of unpleasant but non-painful cold vs hot temperatures. Pain intensity and unpleasantness ratings were significantly higher for heat stimuli applied to the foot vs hand. In contrast, there was no significant body site difference for pain intensity or unpleasantness ratings of cold stimuli. All of these results reveal important differences in the processing of cold vs hot stimuli. These differences could be exploited to differentiate processing relevant to discriminative vs affective components of somesthetic perception, in both the innocuous and noxious ranges.
在12名健康志愿者中对热感觉系统进行了心理物理学评估，这些志愿者涵盖了可耐受温度的整个范围。受试者将一只手或脚放入温度可控的水浴中后，对以下方面进行评分：(1) 感知到的热强度，(2) 感知到的愉悦或不愉悦程度，以及(3) 感知到的疼痛强度。特别令人感兴趣的是这三种感知测量之间的相互关系，以及热刺激和冷刺激之间的差异。热刺激和冷刺激在感知强度与（不）愉悦程度之间的关系有所不同。具体而言，对于给定的感知热强度，冷刺激被评为比热刺激不那么愉悦或更不愉悦。同样，对于给定的疼痛强度，冷刺激被评为比热刺激更不愉悦。随着温暖温度升高和寒冷温度降低，刺激在被感知为疼痛之前先被感知为不愉悦。热刺激从不愉悦到疼痛的转变温度差异平均为1.4摄氏度，而冷刺激的相同差异平均为5.6摄氏度。因此，在不愉悦但无疼痛的寒冷与炎热温度范围上存在四倍的差异。施加在脚上的热刺激的疼痛强度和不愉悦程度评分显著高于施加在手上的。相比之下，冷刺激的疼痛强度或不愉悦程度评分在身体部位上没有显著差异。所有这些结果揭示了冷刺激与热刺激处理过程中的重要差异。这些差异可用于区分与躯体感觉辨别性和情感性成分相关的处理，无论是在无害还是有害范围内。
