Yessick Lindsey R, Pukall Caroline F, Ioachim Gabriela, Chamberlain Susan M, Stroman Patrick W
Department of Psychology, Queen's University, Kingston, ON, Canada.
Centre for Neuroscience Studies, Queen's University, Kingston, ON, Canada.
Front Pain Res (Lausanne). 2021 Jun 17;2:682484. doi: 10.3389/fpain.2021.682484. eCollection 2021.
Provoked Vestibulodynia (PVD) is the most common vulvodynia subtype (idiopathic chronic vulvar pain). Functional magnetic resonance imaging (fMRI) studies indicate that women with PVD exhibit altered function in a number of pain modulatory regions in response to noxious stimulation, such as in the secondary somatosensory cortex, insula, dorsal midcingulate, posterior cingulate, and thalamus. However, previous neuroimaging studies of PVD have not examined periods of time before and after noxious stimulation or investigated functional connectivity among pain modulatory regions. Fourteen women with PVD and 14 matched Control participants underwent five fMRI runs with no painful stimuli interleaved randomly with five runs with calibrated, moderately painful heat stimuli applied to the thenar eminence. As recent findings indicate that pain processing begins before and continues after painful stimulation, 2-min periods were included in each run before and after the stimulus. Functional brain connectivity was assessed during both trials of Pain and No Pain stimulation for each group using structural equation modeling (SEM). Analyses of variance (ANOVAs) on connectivity values demonstrated significant main effects of study condition, and group, for connectivity among pain modulatory regions. Most of the differences between the Pain and No Pain conditions found only in the PVD group take place before (i.e., thalamus to INS, ACC to S1, thalamus to S1, and thalamus to S2) and after pain stimulation (i.e., INS to amygdala, PPC to S1, and thalamus to S2). Such differences were not observed in the Control group. These findings further support previous results indicating that women with PVD have altered pain processing compared to pain-free women.
激发性前庭痛(PVD)是最常见的外阴痛亚型(特发性慢性外阴疼痛)。功能磁共振成像(fMRI)研究表明,患有PVD的女性在受到伤害性刺激时,一些疼痛调节区域的功能会发生改变,如在次级体感皮层、脑岛、背侧中央扣带回、后扣带回和丘脑。然而,先前关于PVD的神经影像学研究并未考察伤害性刺激前后的时间段,也未研究疼痛调节区域之间的功能连接。14名患有PVD的女性和14名匹配的对照参与者进行了五次fMRI扫描,其中无疼痛刺激的扫描与五次对鱼际肌施加校准后的中度疼痛热刺激的扫描随机交错进行。由于最近的研究结果表明疼痛处理在疼痛刺激之前就开始并在之后持续,所以在每次刺激前后的扫描中都包含了2分钟的时间段。使用结构方程模型(SEM)对每组在疼痛和无疼痛刺激的试验中进行功能性脑连接评估。对连接值的方差分析(ANOVA)表明,研究条件和组别对疼痛调节区域之间的连接有显著的主效应。疼痛和无疼痛条件之间的大多数差异仅在PVD组中出现在疼痛刺激之前(即丘脑到脑岛、前扣带回皮质到初级体感皮层、丘脑到初级体感皮层、丘脑到次级体感皮层)和之后(即脑岛到杏仁核、顶叶后皮质到初级体感皮层、丘脑到次级体感皮层)。对照组未观察到此类差异。这些发现进一步支持了先前的结果,表明与无疼痛的女性相比,患有PVD的女性疼痛处理存在改变。