Centre stéphanois de la douleur, CHU de Saint-Etienne & INSERM U1028, Université Jean Monnet, CRNL-Lyon, 10, rue de la Marandière, 42270 Saint-Priest en Jarez, France.
Centre stéphanois de la douleur, CHU de Saint-Etienne & INSERM U1028, Université Jean Monnet, CRNL-Lyon, 10, rue de la Marandière, 42270 Saint-Priest en Jarez, France.
Rev Neurol (Paris). 2019 Jan-Feb;175(1-2):38-45. doi: 10.1016/j.neurol.2018.08.006. Epub 2018 Oct 11.
Brain functional imaging has been applied to the study of pain since 1991. Then, a plethora of studies around the world looking at pain sensations and their brain correlates was published. Four kinds of studies can be distinguished: i) A first set investigated brain responses to noxious heat stimulations (above the pain threshold) relative to an equivalent warm innocuous stimulation (below the pain threshold). The aim of these studies was to identify the pattern of brain regions involved in the nociceptive processes and they may be considered as descriptive studies rather than explanative studies. Their value was to list for the first time every brain structure that might be playing a role. ii) Secondly, several experimental investigations have explored brain activations when subjects are confronted with unpleasant situations such as seeing or imagining other people in pain (e.g. empathy for pain). Obviously, feeling pain and representing others suffering share a common brain network, indicating that a large part of the regions showing intensity changes are not specific to nociception. iii) The third set of imaging studies is aimed at investigating the functional and structural brain abnormalities that may account for clinical pain states. Unfortunately, a relatively small number of studies provide clear findings that do not allow drawing convincing and generalized conclusions. iv) The last set of studies focused on the modulation of pain experience in humans. Several research groups conducted projects on different factors known to alter pain perception and their associated brain processes with the objective of identifying one or more key regions capable of controlling the pain sensation. In the same vein, investigations have been performed around pain therapies. From the clinician's point of view, it may be seen as complementary to assess pain and analgesic processes. All these aspects of pain research with functional imaging are considered below, including attempts to understand the functional significance of each of the observed activations. v) A special focus will be dedicated to new sophisticated approaches, vi) applied to neuroimaging (e.g. graph theory). These promising techniques and recent electrophysiological investigations bring additional information to our understanding of pain/analgesic processes, particularly for temporal dynamics and connectivity between brain regions.
自 1991 年以来，脑功能成像已被应用于疼痛研究。随后，世界各地发表了大量研究疼痛感觉及其大脑相关性的研究。可以区分出四种类型的研究：i）第一组研究调查了对有害热刺激（高于疼痛阈值）相对于等效温暖无害刺激（低于疼痛阈值）的大脑反应。这些研究的目的是确定参与伤害性过程的大脑区域的模式，它们可以被认为是描述性研究而不是解释性研究。它们的价值在于首次列出可能发挥作用的每个大脑结构。ii）其次，一些实验研究探讨了当受试者面对不愉快的情况（例如看到或想象其他人疼痛（例如对疼痛的同理心）时大脑的激活。显然，感到疼痛和代表他人的痛苦共享共同的大脑网络，表明显示强度变化的大部分区域不是特定于伤害感受的。iii）第三组成像研究旨在研究可能导致临床疼痛状态的大脑功能和结构异常。不幸的是，只有相对较少的研究提供了明确的发现，无法得出令人信服和普遍的结论。iv）最后一组研究集中在人类疼痛体验的调节上。几个研究小组开展了针对已知改变疼痛感知及其相关大脑过程的不同因素的项目，目的是确定一个或多个能够控制疼痛感觉的关键区域。同样，围绕疼痛治疗也进行了调查。从临床医生的角度来看，评估疼痛和镇痛过程可能是一种补充。下面考虑了功能成像的疼痛研究的所有这些方面，包括尝试理解观察到的每个激活的功能意义。v）特别关注新的复杂方法，vi）应用于神经影像学（例如图论）。这些有前途的技术和最近的电生理学研究为我们对疼痛/镇痛过程的理解提供了额外的信息，特别是对于大脑区域之间的时间动态和连通性。
