Abstract：
The thermal grill illusion (TGI) describes a peculiar or even painful percept caused by non-noxious, interlaced warm and cold stimuli. It involves the glutamatergic system and is affected in putatively nociplastic syndromes such as fibromyalgia. The glutamatergic system is also involved in wind-up, that is, the increased activation of spinal neurons following repeated noxious stimulation leading to a temporal summation of perceived stimulus intensity. Here we combined both stimulation methods to further investigate whether non-noxious stimuli as employed in the TGI can lead to a similar summation of perceived stimulus intensity. In an experiment using a full crossover within-subjects design, 35 healthy volunteers received repeated stimuli, either in a thermal grill configuration or simply noxious heat. Both modalities were presented as sequences of 1 lead-in contact, followed by 11 consecutive contacts (each between 1.5 and 3 seconds), with either fast repetition (\"wind-up\" condition), or 2 slow-repeating control conditions. The main analyses concerned the relative pre-to-post sequence changes to quantify putatively wind-up-related effects. Pain ratings and skin conductance level (SCL) increased more strongly in \"wind-up\" than in control conditions. Interestingly, wind-up-related effects were of the same magnitude in TGI as compared to the pain control modality. Further, contact-by-contact SCL tracked how the effect emerged over time. These results indicate that although TGI does not involve noxious stimuli it is amenable to temporal summation and wind-up-like processes. Since both phenomena involve the glutamatergic system, the combination of wind-up with the TGI could yield a promising tool for the investigation of chronic pain conditions. PERSPECTIVE: Using thermal stimuli in an experimental protocol to combine 1) the TGI (painful or peculiar percept from simultaneous cold/warm stimulation) and 2) wind-up (increase in stimulus intensity after repeated exposure) holds promise to investigate pain and thermoceptive mechanisms, and chronic pain conditions.
摘要：
热格栅错觉（TGI）描述了由非有害引起的特殊甚至痛苦的感知，交织的温暖和寒冷的刺激。它涉及谷氨酸能系统，并在诸如纤维肌痛之类的假定不良综合征中受到影响。谷氨酸能系统也参与了结束，也就是说,反复伤害性刺激后脊髓神经元的激活增加，导致感知刺激强度的时间总和。在这里，我们结合了两种刺激方法，以进一步研究TGI中采用的非有害刺激是否可以导致感知刺激强度的相似总和。在使用完全交叉的受试者内设计的实验中，35名健康志愿者接受重复刺激，无论是在热格栅配置中，或者仅仅是有害的热量。两种方式都以1个引入接触的序列表示，接下来是11个连续的触点（每个触点在1.5和3s之间），在快速重复(“结束”条件)的情况下，或两个缓慢重复的控制条件。主要分析涉及相对的前到后序列变化，以量化推定的与结束相关的影响。在“结束”中，疼痛等级和皮肤电导水平（SCL）的增加比对照条件更强。有趣的是,与疼痛控制方式相比，在TGI中与结束相关的影响具有相同的幅度。Further,逐个接触SCL跟踪随着时间的推移效果如何出现。这些结果表明，尽管TGI不涉及有害刺激，但它适合于时间求和和类似缠绕的过程。由于这两种现象都涉及谷氨酸能系统，结束与TGI的结合可以为研究慢性疼痛状况提供有希望的工具.透视：在实验方案中使用热刺激结合a）热烧烤错觉（同时冷/热刺激引起的痛苦或特殊感知）和b）发条（反复暴露后刺激强度增加）有望研究疼痛和感温机制，和慢性疼痛状况。
