The Study On The Structural And Functional Changes Of Mental Disorder Patients Using DTI And FMRI Technology

Mental disorders have a high prevalence rate worldwide.The current treatments are not always effective and many patients are nonresponders,which causes a huge burden to economy and society.Although the pathophysiological process and etiology of mental disorders still remain elusive,increasing evidence has shown that abnormal brain connectivity exist in patient group.White matter fibers constitute the biological basis of the structural connectivity and functional connectivity.More importantly,the maturation time of white matter coincides with the average onset age of mental disorder patients.It is of great importance to explore the abnormality of white matter tracts.However,previous studies considered white matter tract as a whole,ignoring the heterogeneous micro structural changes along the tracts.Moreover,the relation between tract-based functional connectivity and structural connectivity could provide the anatomical and functional coupling characteristics underlying the pathophysiology.In this study,we combined multimodal imaging techniques including diffusion tensor imaging(DTI)and resting state functional magnetic imaging(rs-fMRI),to explore whether the heterogeneity existed along the tracts,whether the local diffusion properties along the tracts have predictive values for treatment effect and how tracts structural property interacts with their tract-based functional connectivity.There are 30 drug-naive first-episode psychosis(DN-FEP)patients and 26 matched healthy controls in our schizophrenia study.Moreover,61 drug-naive obsessive-compulsive disorders and 40 matched healthy controls were included in our OCD study.We conducted the comparisons of functional and structural connectivity between healthy controls and the patients.We also predicted the antipsychotic treatment effect using these biomarkers for DN-FEP patients.In addition,metacognition plays an important role in mental disorders.We found DN-FEP patients had microstructural deficits in left occipital corpus callosum(CC),middle right arcuate fasciculus(AF)and middle right inferior frontal occipital fasciculus(IFOF).Middle temporal CC had significant predictive power for 8-week treatment effect in FEP patients.Furthermore,abnormal functional connectivity was found between bilateral parieto-occipital sulcus and within the left dorsal visual pathway.As for OCD patients,anterior-frontal CC tract and left anterior thalamic radiation showed white matter integrity deficits.The anterior-frontal corpus callosum deficits were related to the functional connectivity abnormality between bilateral orbital regions.Our findings could provide useful biomarkers for the diagnosis and treatment of mental disorder patients.