Zhang Zhiqiang, Xu Qiang, Liao Wei, Wang Zhengge, Li Qian, Yang Fang, Zhang Zongjun, Liu Yijun, Lu Guangming
Department of Medical Imaging, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China.
State Key Laboratory of Analytical Chemistry for Life Science, Nanjing University, Nanjing, China.
Hum Brain Mapp. 2015 Jul;36(7):2756-66. doi: 10.1002/hbm.22805. Epub 2015 Apr 16.
Amplitude and functional connectivity are two fundamental parameters for describing the spontaneous brain fluctuations. These two parameters present close coupling in physiological state, and present different alteration patterns in epilepsy revealed by functional MRI (fMRI). We hypothesized that the alteration of coupling between these two imaging parameters may be underpinned by specific pathological factors of epilepsy, and can be employed to improve the capability for epileptic focus detection. Forty-seven patients (26 left- and 21 right-sided) with mesial temporal lobe epilepsy (mTLE) and 32 healthy controls underwent resting-state fMRI scans. All patients were detected to have interictal epileptic discharges on simultaneous electroencephalograph (EEG) recordings. Amplitude-connectivity coupling was calculated by correlating amplitude and functional connectivity density of low-frequency brain fluctuations. We observed reduced amplitude-connectivity coupling associated with epileptic discharges in the mesial temporal regions in both groups of patients, and increased coupling associated with epilepsy durations in the posterior regions of the default-mode network in the right-sided patients. Moreover, we proposed a new index of amplitude subtracting connectivity, which elevated imaging contrast for differentiating the patients from the controls. The findings indicated that epileptic discharges and chronic damaging effect of epilepsy might both contribute to alterations of amplitude-connectivity coupling in different pivotal regions in mTLE. Investigation on imaging coupling provides synergistic approach for describing brain functional changing features in epilepsy.
振幅和功能连接性是描述大脑自发波动的两个基本参数。这两个参数在生理状态下呈现紧密耦合，而在功能磁共振成像（fMRI）显示的癫痫中呈现不同的变化模式。我们假设这两个成像参数之间耦合的改变可能由癫痫的特定病理因素所支撑，并且可用于提高癫痫病灶检测能力。47例内侧颞叶癫痫（mTLE）患者（左侧26例，右侧21例）和32名健康对照者接受静息态fMRI扫描。所有患者在同步脑电图（EEG）记录中均检测到发作间期癫痫放电。通过将低频脑波动的振幅与功能连接密度进行相关分析来计算振幅-连接性耦合。我们观察到两组患者内侧颞叶区域与癫痫放电相关的振幅-连接性耦合降低，而右侧患者默认模式网络后部区域与癫痫病程相关的耦合增加。此外，我们提出了一种新的振幅减去连接性指数，该指数提高了区分患者与对照者的成像对比度。这些发现表明，癫痫放电和癫痫的慢性损伤效应可能都导致了mTLE不同关键区域的振幅-连接性耦合改变。对成像耦合的研究为描述癫痫中的脑功能变化特征提供了协同方法。
