Center for Neuroplasticity and Pain (CNAP), Department of Health Science and Technology, Aalborg University, Aalborg, Denmark.
Center for Neuroplasticity and Pain (CNAP), Department of Health Science and Technology, Aalborg University, Aalborg, Denmark.
J Pain. 2023 May;24(5):796-811. doi: 10.1016/j.jpain.2022.12.004. Epub 2022 Dec 13.
Prolonged experimental pain models can help assess cortical mechanisms underlying the transition from acute to chronic pain such as resting-state functional connectivity (rsFC), especially in early stages. This crossover study determined the effects of 24-hour-capsaicin-induced pain on the default mode network rsFC, a major network in the dynamic pain connectome. Electroencephalographic rsFC measured by Granger causality was acquired from 24 healthy volunteers (12 women) at baseline, 1hour, and 24hours following the application of a control or capsaicin patch on the right forearm. The control patch was received maximum 1 week before the capsaicin patch. Following 24hours, the patch was cooled and later heated to assess rsFC changes in response to pain relief and facilitation, respectively. Compared to baseline, decreased rsFC at alpha oscillations (8-10Hz) was found following 1hour and 24hours of capsaicin application for connections projecting from medial prefrontal cortex (mPFC) and right angular gyrus (rAG) but not left angular gyrus (lAG) or posterior cingulate cortex (PCC): mPFC-PCC (1hour:P < .001, 24hours:P = .002), mPFC-rAG (1hour:P < .001, 24hours:P = .001), rAG-mPFC (1hour:P < .001, 24hours:P = .001), rAG-PCC (1hour:P < .001, 24hours:P = .004). Comparable decreased rsFC following 1hour and 24hours (P≤0.008) was found at beta oscillations, however, decreased projections from PCC were also found: PCC-rAG (P≤0.005) and PCC-lAG (P≤0.006). Pain NRS scores following 24hours (3.7±0.4) was reduced by cooling (0.3±0.1, P = .004) and increased by heating (4.8±0.6, P = .016). However, neither cooling nor heating altered rsFC. This study shows that 24hours of experimental pain induces a robust decrease in DMN connectivity that persists during pain relief or facilitation suggesting a possible shift to attentional and emotional processing in persistent pain. PERSPECTIVE: This article shows decreased DMN connectivity that might reflect possible attentional and emotional changes during acute and prolonged pain. Understanding these changes could potentially help clinicians in developing therapeutic methods that can better target these attentional and emotional processes before developing into more persistent states.
长时间的实验性疼痛模型可以帮助评估从急性到慢性疼痛转变的皮质机制，例如静息状态功能连接（rsFC），尤其是在早期阶段。这项交叉研究确定了 24 小时辣椒素诱导疼痛对默认模式网络 rsFC 的影响，默认模式网络是动态疼痛连接组中的主要网络。通过格兰杰因果关系测量的脑电图 rsFC 是在基线、应用对照或辣椒素贴片后 1 小时和 24 小时从 24 名健康志愿者（12 名女性）中获得的，右侧前臂。对照贴片在辣椒素贴片前最多 1 周接受。24 小时后，贴片冷却后加热，分别评估疼痛缓解和促进时 rsFC 的变化。与基线相比，在应用辣椒素后 1 小时和 24 小时，内侧前额叶皮层（mPFC）和右侧角回（rAG）投射的 rsFC 呈 alpha 振荡（8-10Hz）降低，但左侧角回（lAG）或后扣带回皮层（PCC）则没有：mPFC-PCC（1 小时：P<.001，24 小时：P=.002），mPFC-rAG（1 小时：P<.001，24 小时：P=.001），rAG-mPFC（1 小时：P<.001，24 小时：P=.001），rAG-PCC（1 小时：P<.001，24 小时：P=.004）。同样，在 beta 振荡下也发现了 1 小时和 24 小时后类似的 rsFC 降低（P≤0.008），但也发现了 PCC 投射的降低：PCC-rAG（P≤0.005）和 PCC-lAG（P≤0.006）。24 小时后疼痛 NRS 评分（3.7±0.4）通过冷却（0.3±0.1，P=.004）降低，通过加热（4.8±0.6，P=.016）升高。然而，冷却和加热都没有改变 rsFC。这项研究表明，24 小时的实验性疼痛会导致 DMN 连接的强烈降低，这种降低在疼痛缓解或促进期间持续存在，这表明在持续性疼痛中可能会出现注意力和情绪处理的转变。观点：本文显示 DMN 连接的降低可能反映了急性和持续性疼痛期间的注意力和情绪变化。了解这些变化可能有助于临床医生在发展更持久状态之前，开发能够更好地针对这些注意力和情绪过程的治疗方法。
