基于定向传递函数的癫痫因效性脑网络动态分析

Dynamic analysis of epileptic causal brain networks based on directional transfer function

癫痫是一种脑网络连接失调的神经系统疾病,从有向功能连通性的角度分析癫痫发作过程的脑网络机制具有重要的研究价值。本文首先对不同频段的癫痫脑电信号在发作间期、发作前期和发作期以定向传递函数方法构建因效性脑网络,并分析在不同状态下脑网络信息传递的途径及动态变化过程,最后对癫痫脑网络的特征属性的动态变化进行分析。结果表明,从发作间期到发作期癫痫脑网络的拓扑结构由趋向随机网络转变成趋向规则网络,整个脑网络的节点连接呈现出逐渐下降的趋势,但是在额区、颞区、枕区的内部节点之间的通路连接数增加,在病灶区域存在大量信息流出的枢纽节点。α波、β波和γ波的发作期全局效率明显高于发作间期和发作前期,聚类系数变化趋势表现为发作前期大于发作期,发作期大于发作间期,其中额区、颞区、顶叶区的聚类系数明显增加。本文的研究结果说明,对癫痫因效性脑网络的拓扑结构和特征参数的动态分析可以构建出癫痫发作全过程的动态变化模型,今后在癫痫病灶的定位和癫痫发作预测方面具有重要的研究价值。

Epilepsy is a neurological disease with disordered brain network connectivity.It is important to analyze the brain network mechanism of epileptic seizure from the perspective of directed functional connectivity.In this paper,causal brain networks were constructed for different sub-bands of epileptic electroencephalogram(EEG)signals in interictal,preictal and ictal phases by directional transfer function method,and the information transmission pathway and dynamic change process of brain network under different conditions were analyzed.Finally,the dynamic changes of characteristic attributes of brain networks with different rhythms were analyzed.The results show that the topology of brain network changes from stochastic network to rule network during the three stage and the node connections of the whole brain network show a trend of gradual decline.The number of pathway connections between internal nodes of frontal,temporal and occipital regions increase.There are a lot of hub nodes with information outflow in the lesion region.The global efficiency in ictal stage of α,β andγwaves are significantly higher than in the interictal and the preictal stage.The clustering coefficients in preictal stage are higher than in the ictal stage and the clustering coefficients in ictal stage are higher than in the interictal stage.The clustering coefficients of frontal,temporal and parietal lobes are significantly increased.The results of this study indicate that the topological structure and characteristic properties of epileptic causal brain network can reflect the dynamic process of epileptic seizures.In the future,this study has important research value in the localization of epileptic focus and prediction of epileptic seizure.