Second Clinical School, Lanzhou University, Lanzhou, 730000, China.
Department of Magnetic Resonance, Lanzhou University Second Hospital, Lanzhou, 730000, China.
J Headache Pain. 2021 Dec 11;22(1):147. doi: 10.1186/s10194-021-01354-z.
Accumulating studies have indicated a wide range of brain alterations with respect to the structure and function of classic trigeminal neuralgia (CTN). Given the dynamic nature of pain experience, the exploration of temporal fluctuations in interregional activity covariance may enhance the understanding of pain processes in the brain. The present study aimed to characterize the temporal features of functional connectivity (FC) states as well as topological alteration in CTN.
Resting-state functional magnetic resonance imaging and three-dimensional T1-weighted images were obtained from 41 CTN patients and 43 matched healthy controls (HCs). After group independent component analysis, sliding window based dynamic functional network connectivity (dFNC) analysis was applied to investigate specific FC states and related temporal properties. Then, the dynamics of the whole brain topological organization were estimated by calculating the coefficient of variation of graph-theoretical properties. Further correlation analyses were performed between all these measurements and clinical data.
Two distinct states were identified. Of these, the state 2, characterized by complicated coupling between default mode network (DMN) and cognitive control network (CC) and tight connections within DMN, was expressed more in CTN patients and presented as increased fractional windows and dwell time. Moreover, patients switched less frequently between states than HCs. Regarding the dynamic topological analysis, disruptions in global graph-theoretical properties (including network efficiency and small-worldness) were observed in patients, coupled with decreased variability in nodal efficiency of anterior cingulate cortex (ACC) in the salience network (SN) and the thalamus and caudate nucleus in the subcortical network (SC). The variation of topological properties showed negative correlation with disease duration and attack frequency.
The present study indicated disrupted flexibility of brain topological organization under persistent noxious stimulation and further highlighted the important role of "dynamic pain connectome" regions (including DMN/CC/SN) in the pathophysiology of CTN from the temporal fluctuation aspect. Additionally, the findings provided supplementary evidence for current knowledge about the aberrant cortical-subcortical interaction in pain development.
大量研究表明，经典三叉神经痛（CTN）在结构和功能方面存在广泛的脑改变。鉴于疼痛体验的动态性质，探索区域间活动协方差的时间波动可能会增强对大脑疼痛过程的理解。本研究旨在描述 CTN 中功能连接（FC）状态的时间特征以及拓扑改变。
从 41 例 CTN 患者和 43 例匹配的健康对照者（HCs）中获得静息态功能磁共振成像和三维 T1 加权图像。在组独立成分分析后，应用滑动窗口基于动态功能网络连接（dFNC）分析来研究特定的 FC 状态和相关的时间特性。然后，通过计算图论性质的变异系数来估计整个大脑拓扑组织的动态。进一步对所有这些测量值与临床数据进行相关性分析。
确定了两种不同的状态。其中，以默认模式网络（DMN）和认知控制网络（CC）之间复杂的耦合以及 DMN 内的紧密连接为特征的状态 2，在 CTN 患者中表达更为明显，表现为分数窗口和停留时间增加。此外，患者之间的状态转换频率低于 HCs。关于动态拓扑分析，观察到患者的全局图论性质（包括网络效率和小世界性）受到破坏，同时注意网络（SN）的前扣带皮层（ACC）和丘脑以及纹状体的节点效率变异性降低，以及皮质下网络（SC）。拓扑性质的变化与疾病持续时间和发作频率呈负相关。
本研究表明，在持续的有害刺激下，大脑拓扑组织的灵活性受到破坏，并进一步从时间波动方面强调了“动态疼痛连接组”区域（包括 DMN/CC/SN）在 CTN 病理生理学中的重要作用。此外，研究结果为当前关于疼痛发展中皮质-皮质下相互作用异常的知识提供了补充证据。
