MRI-based Modular Brain Network Study Of Schizophrenia

Schizophrenia is a common severe mental disorder,often accompanied by related symptoms such as cognitive abnormalities and emotional dysfunction.At present,it has been found that the disconnectivity of brain structure and functional are intrinsically linked to the underlying pathophysiological mechanisms of schizophrenia.As an important part of complex brain networks,the role of modules in the pathological mechanism of Schizophrenia is unclear.Moreover,the abnormal relationship between structure and function remains to be studied.The current study explored alterations of modular organization in the brain structural network of Schizophrenia.The whole-brain white matter fibre tracking was carried out on the diffusion tensor image using Tractography.The fibre density structure connection matrix was constructed and divided into seven modules.Then the global,module and node levels were calculated to evaluate the network topology properties.The results showed that global efficiency and rich-club coefficient were decreased in Schizophrenia,indicating that the connections between the rich nodes in the structural network were disrupted,and the network information integration ability was reduced.It was also found that modularity was increased,and the modular separation index in visual module and sommatomoto module was increased,but default module decreased.These results suggest that schizophrenia has abnormal brain structure connectivity at the global level.The topological connectivity between different modules in the network is impaired,providing important insights into the further understanding of the relationship between brain structural connectivity and disease pathology in schizophrenia clue.In addition,we constructed functional networks using f MRI and assessed module connectivity at the whole-brain,module,and node levels and relationships with clinical variables,using the same methods used for structural networks.In addition,the abnormalities in coupling at the whole-brain and module levels were explored by defining correlation coefficients of structure and functional connectivity as structure-function coupling.The results indicated that default module was more segregated from other modules in the functional brain network of Schizophrenia,and there were abnormal connections within and between modules that involved all modules.Some abnormalities were significantly correlated with disease severity and duration.In addition,the degree of structure-function coupling increased in the whole brain and visual moddule.That indicates abnormal functional module connectivity is a striking feature of schizophrenia,and the relationship between neuroanatomical structure and function activity is disordered and manifested at the whole brain and module level.In summary,this paper elucidates the abnormalities in brain module connectivity in schizophrenia from three different perspectives: structure,function,and structurefunction coupling,and from three levels: the global,module,and node levels.These findings demonstrate that modular connections have distinct abnormal patterns in structural and functional networks and play an important role in the physiopathological mechanisms of schizophrenia,underlining the importance of complex structure-function relationships in the disease.