健康与遗传心理学研究室知识库

疼痛是一种同时受心理和生理影响的复杂的感觉和情绪体验，因药物镇痛的局限性和易依赖性，当前对于非药物镇痛的研究吸引了来自多个领域研究者的关注。甩手动作镇痛作为一种下意识的日常镇痛策略，其神经机理尚未明了。为探究动作镇痛的特征及其脑机制，本研究通过系列实验对比了甩手和非甩手后一定时间内，被试对激光诱发疼痛的感受性变化及其脑响应。研究一发现当给予被试相同物理强度的刺激，其在高频甩手后对疼痛刺激的评分要显著低于无动作条件，证实了动作的镇痛作用。研究二进一步探究了在刺激手动作后不同间隔时间 (1s, 15s, 20s, 30s)施加疼痛刺激对疼痛评分的影响，结果发现间隔is时个体对疼痛强度评分最低，且随着间隔时间增加，疼痛强度评分有回升趋势，证明动作镇痛效果的时间效应。研究三中通过对比运动刺激手和非刺激手，考察了动作镇痛的空间效应。结果表明被试只在运动刺激手的条件下，对疼痛的强度评分才会出现降低，说明动作的镇痛范围是局部的，即存在空间效应。最后，研究四利用脑电技术，同时探究了动作镇痛的时间效应和空间效应及其脑机制。行为学上，我们得到了与上述实验趋势一致的结果。在脑电时域结果上，相比于其他条件，被试对刺激手动作后is施加的疼痛刺激的脑响应(N1和N2-P2)幅度最小，这为行为学结果提供了神经基础;在时频域结果上，S1条件(刺激手甩手之后is施加疼痛刺激)下LEP幅度显著低于S15(刺激手甩手之后15s施加疼痛刺激)、CS15(非刺激手甩手之后15s施加疼痛刺激)和Ctrl条件(没有甩手动作的基线条件)，这与时域结果相一致;对于a-ERD和刺激前的Pre-alpha, Pre-beta, S1条件和CS1条件(非刺激手甩手之后is施加疼痛刺激)下振荡幅度均呈现相同模式，而S15和CS15两个条件下振荡幅度也呈现相同模式，与S1和CS1的振荡趋势与之相反。上述结果表明:(1)动作具有镇痛作用，且这种镇痛作用随时间增长而减小，是一种即时的镇痛，具有时间效应;(2)动作镇痛是一种局部镇痛，具有空间效应。(3)动作镇痛涉及多种机制，既有自下而上的外周调控，也包含自上而下的中枢系统调控机制。

Pain is a complex sensory and emotional experience influenced by mental and physical factors. Due to the limitation of drug analgesia, the research on non-drug analgesia has attracted the attention of researchers in many fields. As a kind of subconscious daily analgesia strategy, the neural mechanism of shaking hand movement-induced analgesia is still not clear. In order to investigate the characteristics of movement-induced analgesia and its cerebral mechanism, this study compared the sensitivity changes of laser-evoked pain and its brain response through a series of experiments. In Study 1，we found that when the stimulation of the same physical intensity was given, the pain intensity ratings after shaking hand were significantly lower than those without movement condition, which confirmed the analgesic effect of the movement. Study 2 further explored the effect of different interval time (1s, 15s, 20s, 30s) between stimulated-hand movement and exerting stimulation on pain intensity ratings. The result showed that individuals reported the lowest ratings when the interval time was 1s. More importantly, pain intensity ratings had a tendency to recover with interval time increased, indicating the temporal effect of movement-induced analgesia. Study 3 explored the spatial effect of movement-induced analgesia by comparing the movement of stimulated-hand and non-stimulated hand. The results showed that only under movement of stimulated-hand condition, the pain intensity ratings appeared to decrease, implying that the analgesic range of movement was regional, that is, the spatial effect of movement-induced analgesia. Finally, we explored temporal and spatial effect of movement-induced analgesia and the brain mechanisms using EEG technology. We got behavioral results consistent with the above experimental trends. In EEG results, the brain response amplitudes (N1 and N2-P2) in response to pain stimulation after stimulated-hand movement with interval time of 1 s were smaller compared to other conditions, which provided a neurological basis for behavioral results. In time-frequency domain, magnitude of laser-evoked potential (LEP) in S 1 condition is significantly lower than those in S 15, CS 15 and Control condition, which is corresponding to results in time domain. For a-ERD (event related desynchronization), Pre-alpha and Pre-beta (EEG oscillations before laser stimulation), magnitudes of EEG oscillation in S 1 and CS 1 conditions show the same pattern while magnitudes of EEG oscillation in S15 and CS15 show reverse pattern. In sum, the above results show: (1) movement can induce analgesic effect and the effect decreases with time goes by (i.e.,the temporal effect); (2) movement mainly induces local analgesic effect (i.e., the spatial effect); (3) Movement-induced analgesia involves a variety of mechanisms, ranging from bottom-up peripheral regulation to top-down central system regulations.