Spatial Properties of Cutaneous Temperature Sensitivity

描述（由申请人提供）：该项目的长期目标是了解热刺激如何整合在皮肤的感觉系统内和之间。这项拟议中的研究将测试在目前资助期间提出的三项新发现的假设，这些新发现对当前的热感受理论提出了质疑：首先，皮肤冷纤维，其中许多在高温下也会“矛盾地”放电，可能有助于温暖纤维受到刺激时的热感觉;第二，31 - 25摄氏度之间的温和冷却可以产生刺痛和/或烧灼感的伤害性感觉（“无害冷伤害性感受”）在静态而非动态接触冷却期间;第三，温暖和寒冷的总和可以通过较大的刺激将接触皮肤中最敏感的部位的较高概率来解释。实验提出，将利用专门设计的热刺激器（1）测试的假设，热烧烤错觉（合成热）的发生是因为当温暖的纤维也被刺激时，冷刺激被编码为热，甚至热痛;（2）通过使用线性热电极阵列研究合成热和局部热来确定这些冷热相互作用的时空特性;（3）检验“无害冷伤害感受”被动态接触皮肤产生的触觉刺激抑制的假说，并探讨其与合成热和局部热相关的伤害感受的关系;以及（4）使用独特的，手柄热刺激器，这将使研究的热感知和集成在整个手的条件下，模仿触觉探索的温度。除了增加我们对正常温度敏感性如何取决于温度，触觉和疼痛之间的相互作用的了解外，拟议研究的结果可能有助于解释由温度引发的神经性疼痛，如冷感觉迟钝和痛觉过敏，如何可能由一种或多种皮肤感觉的传入处理中断引起。

DESCRIPTION (provided by applicant): The long-term goal of this project is to understand how thermal stimulation is integrated within and among the sensory systems of the skin. The proposed research will test hypotheses stemming from three new findings during the present funding period that raise questions about current theories of thermoreception: First, that cutaneous cold fibers, many of which also discharge 'paradoxically' at high temperatures, may contribute to sensations of heat whenever warm fibers are also stimulated; second, that mild cooling between 31degrees -25 degrees C can produce nociceptive sensations of stinging and/or burning ('innocuous-cold nociception') during static, but not dynamic, contact cooling; and third, that much of summation of warmth and cold can be accounted for by the higher probability that larger stimuli will contact the most sensitive sites in the skin. Experiments are proposed that will take advantage of specially designed thermal stimulators to (1) test the hypothesis that the Heat Grill Illusion (Synthetic Heat) occurs because cool stimulation is encoded as heat, and even heat pain, when warm fibers are also stimulated; (2) determine the spatiotemporal properties of these warm-cold interactions via studies of Synthetic Heat and Paradoxical Heat using a linear thermode array; (3) test the hypothesis that 'innocuous-cold nociception' is suppressed by tactile stimulation produced by dynamic contact with the skin, and investigate its relationship to the nociceptive sensations associated with Synthetic Heat and Paradoxical Heat; and (4) provide further tests of the 'sensitive-site' explanation of spatial summation using a unique, handgrip thermal stimulator that will enable studies of thermal perception and integration throughout the hand under conditions that mimic haptic exploration of temperature. In addition to increasing our knowledge of how normal temperature sensitivity depends upon interactions among the senses of temperature, touch, and pain, the results of the proposed studies may help to explain how neuropathic pains that are triggered by temperature, such as cold dysesthesias and hyperalgesias, can arise from disruption of afferent processing in one or more of the cutaneous senses.