The interference of experimental pain and cognition in patients suffering from chronic pain

急性疼痛是我们身体的一个重要警告信号。它是组织损伤的信号，可以让我们迅速从危险的源头撤出来保护自己。因此，疼痛感知和疼痛处理优先于其他不太相关的认知过程，从而导致疼痛处理和认知之间的干扰。这种所谓的疼痛中断功能在急性疼痛中是有益的，但在慢性疼痛中失去了保护功能。然而，患有慢性疼痛的患者经常报告疼痛引起的认知障碍，特别是注意力和记忆缺陷，这损害了他们的生活质量。迄今为止，疼痛的中断功能已经在健康样本中进行了几乎完全的研究，首次深入了解了疼痛和认知干扰的神经机制。不幸的是，缺乏关于疼痛对慢性疼痛患者有害影响的实验研究。因此，计划研究的目的是调查慢性腰痛患者和慢性偏头痛患者的实验性疼痛的中断效应，并将其与健康对照进行比较。我们的目标是确定心理和神经元的预测增强或减少干扰疼痛和认知。疼痛的中断效应将通过视觉分类任务和记忆任务来研究，其中在呈现中性图像的同时，将疼痛的电刺激应用于下背部和前额。我们预计慢性疼痛患者在疼痛系统的持续激活以及由此导致的心理（如注意偏差、疼痛相关焦虑）和神经处理的变化下，会表现出更大的疼痛刺激对任务表现的不利影响。在这里，我们想调查疼痛患者是否表现出一般疼痛的增强中断功能，或者实验性疼痛的影响是否在受慢性疼痛影响的身体部位（下背部或头部）增强。除了行为和生理数据外，我们还将使用（功能性）磁共振成像（fMRI；形态学和静息状态连接）获取神经数据，以识别对疼痛有害影响的高度脆弱性的心理和/或神经生物学标记。从长远来看，这些标记物可以用于识别易受疼痛中断影响的患者，并在多模式疼痛治疗中优化其治疗方法。

Acute pain is an important warning signal for our body. It signals tissue damage and allows the rapid withdrawal from the source of danger to protect ourselves. Pain perception and pain processing are therefore prioritized over other, less relevant cognitive processes, thus leading to an interference between pain processing and cognition. This so called interruptive function of pain is physiologically beneficial in acute pain, but has lost its protective function in chronic pain. However, patients suffering from chronic pain frequently report pain-induced cognitive disturbances, particularly attention and memory deficits, that impair their quality of life. To date, the interruptive function of pain has been almost entirely investigated in healthy samples, giving first insights into the neural mechanisms underlying the interference of pain and cognition. Unfortunately, well-conducted, experimental studies about the detrimental effects of pain in patients suffering from chronic pain are lacking. It is therefore the aim of the planned study to investigate the interruptive effect of experimental pain in patients suffering from chronic low back pain and patients suffering from chronic migraine and to compare them to healthy controls. We aim to identify psychological and neuronal predictors of enhanced or decreased interference of pain and cognition. The interruptive effect of pain will be investigated using a visual categorization task and a memory task, in which painful electrical stimuli will be applied to the lower back and the forehead concurrently to the presentation of neutral images. We expect that patients suffering from chronic pain will show greater detrimental effects of concurrent painful stimulation on task performance due to the constant activation of the pain system and the resulting changes in psychological (e.g. attentional biases, pain-related anxiety) and neural processing. Here, we want to investigate whether pain patients show an enhanced interruptive function of pain in general or whether the effects of experimental pain are augmented at the body site (lower back or head) that is affected by the chronic pain condition. In addition to behavioral and physiological data, we will acquire neural data using (functional) magnetic resonance imaging (fMRI; morphology and resting state connectivity) to identify psychological and/or neurobiological markers of a heightened vulnerability to the detrimental effects of pain. Such markers could, in the long-term, be used to identify patients prone to the interruptive effect of pain and to optimize their therapeutic treatment within a multimodal pain therapy.