全面性棘慢复合波相关神经网络的EEG-fMRI研究

全面性癫痫的脑电图(EEG)呈全面性棘慢复合波放电(GSWDs),近来研究表明GSWDs并非"全面地"累及整个大脑,而是与特异的神经网络相关。同步脑电图联合功能磁共振(EEG-fMRI)技术可无创、高时空分辨率地了解痫性电活动时各脑区的代谢功能变化。EEG-fMRI研究已发现丘脑-基底节-皮质网络在GSWDs的产生与维持中起重要作用。与GSWDs相关的功能磁共振(fMRI)信号变化规律:前额叶、额顶叶、后扣带回、楔前叶出现相似的负激活(deactivation)信号,丘脑出现较为一致的激活(activation)信号,基底节出现负激活信号。进一步研究发现,fMRI信号随GSWDs出现的时程动态变化,皮质神经元活动可能先于丘脑出现,但不同EEG-fMRI研究的皮质激活部位存在个体化表现,散在地分布于额叶、顶叶等皮质区域。进一步发展更加复杂的分析方法揭示fMRI信号的时程变化规律,研究GSWDs产生的起始、传导和维持涉及的神经网络,揭示全面性癫痫的行为表现、药物治疗反应与神经网络的关系是未来EEG-fMRI研究的方向。

EEG-fMRI studies on the neural networks of the generalized spike and wave discharges: an overview

This paper generalizes the seizures characterized with paroxysmal generalized spike and wave discharges (GSWDs) in the EEG. Recent studies showed that GSWDs disrupt specific neural networks only rather than the entire brain homogenously. Simultaneous EEG and functional MRI (EEG-fMRDI) provides a high spatiotemporal resolution method for uncovering the regions of the brain showing changes in metabolism and blood flow during epileptic activity. Human EEG-fMRI studies to date have revealed the blood oxygenation level dependent (BOLD) signal changes in response to GSWDs in some specific brain regions. Most studies have noted similar BOLD signals decrease in the bilateral cortical regions including frontal, frontal-parietal, posterior cingulated and precuneus cortex, as well as in the basal ganglia, and BOLD signals increase in the bilateral thalamic. Further studies demonstrated that BOLD signals in different regions were dynamic changes in the time course of GSWDs and BOLD changes in the cortical areas occurred before in the thalamus. These cortical-subcortical structures may form the neural networks associated with GSWDs generation and maintenance. More sophisticated analytic techniques will be developed to explore the BOLD time-course of GSWDs and identify the brain structures involved in seizure onset and discharges propagation respectively. The sub-network associated with different behavioral deficits between interical and ictal GSWDs, and the different subtypes of generalized seizures will be further studied. The functional connectivity of the nodes of the neural network of GSWDs can also be further investigated. A better understanding of the neural network responsible for GSWDs generation may help to develop new therapeutic interventions.