Wang Ya, Li Yongxin, Wang Huirong, Chen Yanjun, Huang Wenhua
Institute of Human Anatomy, Southern Medical University, Guangzhou, China.
Electromechanic Engineering College, Guangdong Engineering Polytechnic, Guangzhou, China.
Front Neurol. 2017 May 19;8:209. doi: 10.3389/fneur.2017.00209. eCollection 2017.
Infantile spasms (IS) syndrome is an age-dependent epileptic encephalopathy, which occurs in children characterized by spasms, impaired consciousness, and hypsarrhythmia. Abnormalities in default mode network (DMN) might contribute to the loss of consciousness during seizures and cognitive deficits in children with IS. The purpose of the present study was to investigate the changes in DMN with functional connectivity (FC) and amplitude of low-frequency fluctuation (ALFF), the two methods to discover the potential neuronal underpinnings of IS. The consistency of the two calculate methods of DMN abnormalities in IS patients was also our main focus. To avoid the disturbance of interictal epileptic discharge, our testing was performed within the interictal durations without epileptic discharges. Resting-state fMRI data were collected from 13 patients with IS and 35 sex- and age-matched healthy controls. FC analysis with seed in posterior cingulate cortex (PCC) was used to compare the differences between two groups. We chose PCC as the seed region because PCC is the only node in the DMN that directly interacts with virtually all other nodes according to previous studies. Furthermore, the ALFF values within the DMN were also calculated and compared between the two groups. The FC results showed that IS patients exhibited markedly reduced connectivity between posterior seed region and other areas within DMN. In addition, part of the brain areas within the DMN showing significant difference of FC had significantly lower ALFF signal in the patient group than that in the healthy controls. The observed disruption in DMN through the two methods showed that the coherence of brain signal fluctuation in DMN during rest was broken in IS children. Neuronal functional impairment or altered integration in DMN would be one neuroimaging characteristic, which might help us to understand the underlying neural mechanism of IS. Further studies are needed to determine whether the disturbed FC and ALFF observed in the DMN are related to cognitive performance in IS patients.
婴儿痉挛（IS）综合征是一种与年龄相关的癫痫性脑病，发生于儿童，其特征为痉挛、意识障碍和高度节律失调。默认模式网络（DMN）异常可能导致IS患儿癫痫发作时意识丧失及认知缺陷。本研究旨在通过功能连接（FC）和低频振幅（ALFF）这两种方法来探究DMN的变化，以发现IS潜在的神经学基础。IS患者中DMN异常的两种计算方法的一致性也是我们的主要关注点。为避免发作间期癫痫放电的干扰，我们在无癫痫放电的发作间期进行测试。收集了13例IS患者和35例性别及年龄匹配的健康对照的静息态功能磁共振成像（fMRI）数据。采用后扣带回皮质（PCC）作为种子点的FC分析来比较两组之间的差异。我们选择PCC作为种子区域是因为根据先前研究，PCC是DMN中唯一与几乎所有其他节点直接相互作用的节点。此外，还计算并比较了两组DMN内的ALFF值。FC结果显示，IS患者后种子区域与DMN内其他区域之间的连接性明显降低。此外，DMN内部分显示FC有显著差异的脑区，患者组的ALFF信号明显低于健康对照组。通过这两种方法观察到的DMN破坏表明，IS患儿静息时DMN中脑信号波动的连贯性被打破。DMN中的神经元功能损害或整合改变将是一种神经影像学特征，这可能有助于我们理解IS的潜在神经机制。需要进一步研究来确定DMN中观察到的FC和ALFF紊乱是否与IS患者的认知表现有关。
