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.
Neuroimage Clin. 2022;33:102907. doi: 10.1016/j.nicl.2021.102907. Epub 2021 Dec 6.
The angular gyrus (AG) is a common hub in the pain networks. The role of the AG during pain perception, however, is still unclear. This crossover study examined the effect of tonic pain on resting state functional connectivity (rsFC) of the AG under eyes closed (EC) and eyes open (EO). It included two sessions (placebo/pain) separated by 24 hours. Pain was induced using topical capsaicin (or placebo as control) on the right forearm. Electroencephalographic rsFC assessed by Granger causality was acquired from 28 healthy participants (14 women) before (baseline) and 1-hour following the application of placebo/capsaicin. Subjects were randomly assigned and balanced to groups of recording sequence (EC-EO, EO-EC). Decreased rsFC at alpha-1 and beta, but not alpha-2, oscillations was found during pain compared to baseline during EC only. For alpha-1, EC-EO group showed a pain-induced decrease only among connections between the right AG and each of the posterior cingulate cortex (PCC, P = 0.002), medial prefrontal cortex (mPFC, P = 0.005), and the left AG (P = 0.023). For beta rsFC, the EC-EO group showed a bilateral decrease in rsFC spanning the connections between the right AG and mPFC (P = 0.015) and between the left AG and each of PCC (P = 0.004) and mPFC (P = 0.026). In contrast, the EO-EC group showed an increase in beta rsFC only among connections between the left AG and each of PCC (P = 0.012) and mPFC (P = 0.036). No significant change in the AG rsFC was found during EO. These results provide insight into the involvement of the AG in pain perception and reveal methodological considerations when assessing rsFC during EO and EC.
角回是疼痛网络中的一个常见枢纽。然而，角回在疼痛感知中的作用尚不清楚。本项交叉研究通过静息态功能磁共振成像（rsFC）观察闭眼（EC）和睁眼（EO）状态下，持续疼痛对角回 rsFC 的影响。该研究共纳入 28 名健康参与者（14 名女性），采用右前臂局部涂辣椒素（或安慰剂对照）的方法诱导疼痛，在使用辣椒素或安慰剂 24 小时后分别进行两次实验（安慰剂/疼痛）。在应用辣椒素或安慰剂后 1 小时内，通过 Granger 因果关系评估脑电图 rsFC。参与者随机分为 EC-EO 和 EO-EC 两组，记录顺序平衡。与基线相比，仅在 EC 状态下，疼痛时会观察到 alpha-1 和 beta 频段但非 alpha-2 频段的 rsFC 降低。对于 alpha-1 频段，仅在 EC-EO 组中，与右侧角回和后扣带回皮质（PCC）、内侧前额叶皮质（mPFC）和左侧角回之间的连接中观察到疼痛诱导的 rsFC 降低（P=0.002、0.005 和 0.023）。对于 beta 频段 rsFC，EC-EO 组显示出右侧角回和 mPFC 之间（P=0.015）以及左侧角回和 PCC 及 mPFC 之间（P=0.004 和 0.026）双侧 rsFC 降低。相比之下，EO-EC 组仅在左侧角回和 PCC 及 mPFC 之间的连接中观察到 beta 频段 rsFC 增加（P=0.012 和 0.036）。在 EO 期间，未观察到角回 rsFC 有显著变化。这些结果为角回在疼痛感知中的作用提供了新的认识，并揭示了在评估 EO 和 EC 期间 rsFC 时的方法学考虑因素。
