Wang Ting, Chen Ning, Zhan Wang, Liu Jia, Zhang Junpeng, Liu Qi, Huang Hua, He Li, Zhang Junran, Gong Qiyong
Department of Medical Information Engineering, School of Electrical Engineering and Information, Sichuan University, No.24, South Section One, First Ring Road, Chengdu, 610065, P.R China.
Huaxi MR Research Center (HMRRC), Department of Radiology, West China Hospital of Sichuan University, Chengdu, P.R China.
J Headache Pain. 2015;17:17. doi: 10.1186/s10194-016-0610-4. Epub 2016 Feb 27.
Most migraineurs develop cutaneous allodynia (CA) during migraine, and the underlying mechanism of CA in migraine is thought to be sensitization of the third-order trigeminovascular neurons in the posterior thalamic nuclei. This study aimed to investigate whether the ascending/descending pathway associated with the thalamus is disturbed in migraineurs with CA (MWCA) using effective connectivity analysis of resting-state functional magnetic resonance imaging.
Thirty four migraineurs without aura (14 MWCA and 20 migraineurs without CA (MWoCA)) and 25 matched healthy controls (HC) were recruited in the study. The effective connectivity pathways associated with the posterior thalamus (PTH) were investigated using the Granger causality analysis. We chose bilateral PTH as two individual seeds, and compared MWCA with MWoCA and HC, respectively. Spearman correlation analysis was performed to test the correlation between the abnormal effective connectivity and the allodynia severity of MWCA.
Compared with MWoCA, MWCA showed decreased inflows from the left limbic regions and dorsal medial prefrontal cortex (dmPFC) to the ipsilateral PTH, as well as increased inflow from the right ventral medial prefrontal cortex (vmPFC) to the ipsilateral PTH; no significantly different outflows from the bilateral PTH to other regions were found. Compared with HC, MWCA showed increased outflows from the left PTH to the bilateral vmPFC, decreased outflows from the right PTH to the bilateral temporoparietal areas, decreased inflow from the left parietooccipital area to the ipsilateral PTH, and increased inflows from the right dorsolateral prefrontal cortex and the bilateral temporoparietal areas to the right PTH. Correlation analyses revealed that the disturbed connectivities between PTH and cuneus, as well as PTH and middle frontal gyrus were associated with the allodynia severity of MWCA.
MWCA demonstrated disrupted effective connection pathways between the PTH and other cortical or subcortical regions that participated in multi-dimentional pain processing. Our findings highlight the dysfunctional ascending and descending pain network at the thalamic-level and may help to illuminate the possible pathophysiologic mechanisms of CA.
大多数偏头痛患者在偏头痛发作期间会出现皮肤异常性疼痛（CA），偏头痛中CA的潜在机制被认为是丘脑后核中三级三叉神经血管神经元的敏化。本研究旨在使用静息态功能磁共振成像的有效连接分析，调查伴有CA的偏头痛患者（MWCA）中与丘脑相关的上行/下行通路是否受到干扰。
本研究招募了34名无先兆偏头痛患者（14名MWCA和20名无CA的偏头痛患者（MWoCA））以及25名匹配的健康对照者（HC）。使用格兰杰因果分析研究与丘脑后部（PTH）相关的有效连接通路。我们选择双侧PTH作为两个独立的种子，并分别将MWCA与MWoCA和HC进行比较。进行斯皮尔曼相关分析以测试MWCA异常有效连接与异常性疼痛严重程度之间的相关性。
与MWoCA相比，MWCA显示从左边缘区域和背内侧前额叶皮质（dmPFC）到同侧PTH的流入减少，以及从右腹内侧前额叶皮质（vmPFC）到同侧PTH的流入增加；未发现双侧PTH到其他区域的流出有显著差异。与HC相比，MWCA显示从左PTH到双侧vmPFC的流出增加，从右PTH到双侧颞顶叶区域的流出减少，从左顶枕叶区域到同侧PTH的流入减少，以及从右背外侧前额叶皮质和双侧颞顶叶区域到右PTH的流入增加。相关分析表明，PTH与楔叶以及PTH与额中回之间的连接紊乱与MWCA的异常性疼痛严重程度相关。
MWCA显示PTH与其他参与多维疼痛处理的皮质或皮质下区域之间的有效连接通路中断。我们的研究结果突出了丘脑水平上功能失调的上行和下行疼痛网络，并可能有助于阐明CA可能的病理生理机制。
