Relationship Between White Matter Function And Structure Coupling And Behavioral Phenotypes In Depression

Depression is a common emotional disorder with depressive mood,inhibition of thought and impaired cognitive function as the main clinical features.Once one person suffers from depression,it will bring harm to individuals,families and the society.The rate of morbidity,recurrence and misdiagnosis are high,but the effect of treatment is still poor.The pathogenesis of the depression is not clear currently,which makes through early diagnosis and prevention to reduce the incidence of depression become an urgent problem.Combining various magnetic resonance imaging techniques to explore the pathogenesis of depression and finding objective biomarkers has become a hot issue.Previous studies have paid more attention to gray matter than white matter.However,more and more studies have shown that white matter signals are related to brain functional activities.Functional Magnetic Resonance Imaging(fMRI)and Diffusion Tensor Imaging(DTI)were mostly used to study function or structure of white matter in the brain,but image data onto single modal could not fully depict the changes of patients’ brain.The combination of rest-state fMRI technology with other MRI technologies,especially with DTI,provides material basis and anatomical basis for the study of brain function and structure.The anatomical basis of the functional connectivity is the structure connectivity,and the external representation of structural connectivity is functional connectivity.While functional connectivity as well as structural connectivity has a great impact on understanding of mental illness and human cognitive,but what is more important than single modal analysis is the fusion analysis of function and structure.The relationship between the function and structure of the research is of great significance to further to understand the brain.The human connectome provides a framework of behavior and cognition,and at the present,the key challenge for neuroscience is to understand the relationship between the inter-individual variations in the organization of functional systems within the connectome and the environmental and phenotypic factors.The connectome-wide association studies(CWAS)permitting the exploration of brain-behavior relationships between the entire connectome remain a challenge.In this paper,we used experimental data including rest-state fMRI,DTI and clinical scales to conduct a multimodal fusion analysis of function,structure and behavioral phenotypes.This paper mainly includes the following two parts:1)Studying on abnormal coupling between function and structure of white matter in depression.So as to revealing the relationship between the functional activity and the integrity of microstructure of white matter in depression.From the perspectives of the white matter of whole brain,the network and depth levels of the white matter respectively,we explored the abnormalities of function-structure coupling of white matter in depression.Values of function-structure coupling were used to measure the correlation with clinical scores,and then,them were selected as features to distinguish normal people from depression patients.Results revealed abnormities of the coupling of white matter function and structure from global scale to local scale in depression.Decreased function-structure coupling of whole brain white matter in depression,and there are anomalies in multiple networks as well.The abnormal function-structure coupling in the cingulate tract and deep frontal white matter may be the main potential factors of emotional disorder and cognitive impairment in depression.At the same time,the functional network coupling values and the three-layer coupling values could distinguish normal person from the depression patients with high accuracy,which provided valuable biomarkers for clinical diagnosis,treatment and intervention.2)Correlation between function of white matter and behavioral phenotypes in depression based on multivariate distance matrix regression analysis.Multivariate distance matrix regression(MDMR)analysis based on connectome-wide association studies was used to analyze the correlation between neuroimaging data and behavioral phenotypes,i.e.clinical scale scores.Firstly,White matter regions associated with clinical scales were found by multivariate distance matrix regression analysis,and then,these areas were selected as seeds for post hoc analysis,calculating the functional connectivities between the seeds and white matter voxels in the whole brain.The differences between groups would be found by statistical test.Finally,the correlation between the abnormal functional connectivities and clinical scale scores was measured.Results showed that regions associated with the severity of depressive symptoms were located in the superficial white matter of sensomotor,superior longitudinal tract,and ventral frontal parietal system,providing a new reference for the clinical diagnosis and intervention of depression.In conclusion,this paper revealed the abnormal coupling of white matter function and structure in depression.The correlation between white matter function and clinical phenotypes by multimodal fusion analysis,which provided supports for further exploration of the pathological mechanism of depression and would be beneficial to intervention,diagnosis and treatment of depression.