The Applied Research On Complex Network In Brain Structure Network Of Patients With Epileptic

To date,the human brain is one of the most complex system as we know.The appearance of brain imaging technology makes it possible to explore the structure and function of the brain directly.In this dissertation,the brain structure network was constructed by the magnetic resonance imaging data.The brain structure network of patient with generalized tonic-clonic seizure epilepsy was researched by using the complex networks theory.Voxel-based morphometry(VBM)method was used to analyze the MRI data in normal control group and epilepsy group,and compared the differences of gray matter volume between epileptic patients and normal controls by two-sample t test.Secondly,based on the AAL,the Pearson correlation coefficient was used to constructe the brain structure network of epilepsy group and normal control group.Based on the complex network theory,the “small-world” property and the attributes of the networks were calculated,such as the shortest path length,clustering coefficient,global efficiency and local efficiency.To clarify the differences between the two groups of brain structure network.The results showed that,compared with the normal control group,patients with epilepsy showed significant gray matter volume atrophy in the cerebellum,thalamus,temporal lobe,frontal lobe,cingulate gyrus and other brain regions.The brain structure network of epilepsy group and normal control group exhibited the “small world” properties.The shortest path length and global efficiency of the attributes of the networks were better than those of the control group,while the clustering coefficient and the local efficiency of the normal group were lower than those of the epilepsy group.It had been proved that the increase of the local efficiency of epilepsy group was the result of "balance" of the brain structure network,and it was a kind of compensation to the reduction of the global efficiency of the brain.Based on the CLM cascading failure model,the brain structure network of epileptic patients was studied.Select the areas where the gray matter volume decreased and node degree minimum brain area coincide as the target to attack,in order to analysis the abilities of two groups to resist cascading failures.The brain areas of the structure network were reordered according to the degree order from big to small,then the six brain regions with the smallest node degree area and the atrophy of gray matter volume brain area coincide were selected to attack,the efficiency of the network under the different capacity factor were calculated,and the result was compared with the normal control group.The result showed that compared with normal control group,the brain structure network of patients with epilepsy showed stronger robustness when attacked the nodes with small degree.The result proved that the gray matter volume atrophy in the cerebral cortex of epileptic patients had some damage to the topological structure of the brain structure network,which led to more discrete node appear.So the robustness of structure network of patients with epilepsy was stronger than that of the normal group.The brain nodes with small degree should also be protected,in order to prevent the occurrence of other brain disorders due to the abnormal brain areas associated with epilepsy.