健康与遗传心理学研究室知识库

疼痛，特别是慢性痛能够导致认知上的损伤。本研究主要用事件相关电位C event-related brain potentials, ERPs)的方法来探索疼痛调节认知，特别是注意的神经机制。首先，失匹配负波(Mismatch negativity, MMN)是一种变化相关的听觉事件相关电位(ERPs)成分，它甚至能够在没有注意参与的情况下被诱发并且被认为能够为感觉记忆加工提供一个独特的窗口。研究一是为了探索慢性痛和急性痛是如何影响听觉感觉记忆加工的。在实验一中，我们比较了三叉神经痛Ctrigeminal neuralgia,TN)患者和在人口统计学上相匹配的健康对照组(HCs )在短的(500 ms)和长的(2500 ms)刺激间隔C inter-stimulus intervals, ISIS)下的被标准和偏差听觉刺激诱发的}N。我们发现与HC组相比TN患者在长ISIS条件下的1VIlVIN减弱更强。相关分析的结果表明了在McGill疼痛问卷中的感觉分量表中的分数与1VIIVIN在两个ISI之间波幅的减小量有正相关关系。在实验二中，我们用被试将受放入冰水中来产生的冷压痛范式(CPT)来诱发急性痛，并且在放入冰水之前，之中，之后记录MNIIV o MMN波幅在冷压痛产生的急性痛中显著地减小并且在疼痛消失后立即恢复。这些结果表明急性痛和慢性痛都能够干扰大脑中自动化的变化探测加工。这个研究首次提出了慢性痛病人听觉感觉记忆痕迹衰退的比健康对照组更快，并且实验室诱发的冷压痛也能够改变前注意听觉加工。

在研究二中，我们用视觉oddball范式探索三种不同表情(疼痛，高兴与中性)的人脸分心刺激是否能够在包含少量目标刺激的重复出现的标准刺激中成功诱发出P3a，我们发现疼痛表情与中性表情相比，诱发出的P3a波幅显著增大，而与高兴表情相比没有显著差异。所以在注意资源的分配中，疼痛刺激与其他情绪凸显性刺激一样会占用更多的注意资源。

而在研究三中，我们又探索了在注意参与的不同水平之下(高注意负荷与低注意负荷)，疼痛场景/非疼痛场景/马赛克场景是否能够影响单侧出现的中性人脸表情的加工。N170是一种人脸加工特异的ERP成分，当人脸与另外一种非人脸刺激同时出现时，对人脸表情反应的N170会降低。我们发现当出现疼痛图片时，与非痛图片与打马赛克的图片相比，单侧面孔诱发的N170都会显著降低并且在低注意负荷条件下这种差异更为明显。本实验结果表明疼痛能够增加对早期面孔加工的视觉竞争，并且受到参与的注意水平的影响。

依据以上结果，我们能够得出以下结论:第一，临床慢性痛会影响前注意加工并且造成听觉感觉记忆的损伤;第二，实验室诱发的急性痛也会造成前注意加工的损伤，但这种损伤是暂时的可以恢复的;第三，疼痛相关信息会占用更多的注意资源，这反应在任务无关条件中P3a波幅的增加，但这种增加可能是由于情绪凸显性刺激影响注意资源分配;第四，疼痛相关信息会增加对早期面孔加工的视觉竞争，这表现在对同时出现的单侧人脸刺激反应的N170波幅的减小上，进一步证明了疼痛相关信息能够占用更多的注意加工资源。因此无论是临床慢性痛，实验室诱发痛或者是疼痛相关的信息都可能因为占用过多的注意资源而导致注意加工上的损伤，而1VPVIN则可能可以作为临床疼痛和治疗反应的客观指标。

Pain, especially chronic pain, can lead to cognitive deficits. The present study aims to explore the modulation of pain on attention and its underlying mechanisms using event-related brain potentials (ERPs). Mismatch negativity (MMN) is a change-specific component of the auditory ERPs that is elicited even in the absence of attention and thought to provide a unique window into sensory memory processes. Study 1 was designed to determine how chronic and acute pain affects auditory sensory memory. In experiment 1, MMNs elicited by standard and deviant auditory stimuli at short (500 ms) and long (2500 ms) inter-stimulus intervals (ISIS) were compared between trigeminal neuralgia (TN) patients and demographically matched healthy controls (HCs). The TN patients were found to have stronger attenuation of the MMN at longer ISIS than HCs.

Correlation analysis revealed a significant positive correlation between the sensory subscale of McGill Pain Questionnaire and MMN amplitude reduction across ISI conditions. In experiment 2, MMNs recorded before, during, and after the cold pressor test (CPT), in which acute pain is generating by placing a hand in ice-cold water, were compared in healthy subjects. MMN amplitude was significantly reduced during CPT acute pain exposure and recovered immediately thereafter. These results suggest that both chronic pain and acute pain can interfere with automatic change detection processes in the brain. This study provides the first evidence that chronic pain patients have a faster auditory memory trace decay than HCs, and that experimentally-induced cold pain can also alter pre-attentive auditory processing.

In study 2, we attempt to explore whether three types of expressions (happy, pain and neutral) as distractors in large amount of repetitive standard stimuli, which including rare target stimuli, can elicit P3a in a visual oddball paradigm. We found that pain-related expressions elicited larger P3a than neutral expression, and there was no significant difference between P3a peak amplitude elicited by pain and happy expressions. We can conclude that pain-related stimuli, like other emotional salience stimuli, engage in more attention resources.

While in study 3, we attempt to study in different attention levels (high-load vs. low load), how pain-related/pain-unrelated/scrambled pictures affect unilateral neutral faces induced face processing. N170 is one of specific ERPs elicited by face processing. We found that pain-related pictures, compared with pain-unrelated and scrambled pictures, impaired unilateral faces induced N170. In addition, this kind of reduction is more prominent in low-load attentional condition. The results indicate that pain can increase visual competition with early face processes, and can be affected by the level of attentional load.

According to the results above, we can conclude that chronic pain and experimental induced pain can alter pre-attentive processing and chronic pain can also lead to faster memory trace decay. Furthermore, pain-related information can occupy more attentional resources, it was reflected by increasing P3a amplitudes. It was also proved by the fact that pain-related information increases visual competition with early face categorization processes, which was presented by reduction of N170 induced by unilateral face. Therefore, chronic clinic pain, experimental induced acute pain or pain related information can all lead to the occupation of too much attentional resources, and NIIVIN can be used as objective index of clinical diagnosis and treatment of pain.