Gradient Of Multimodal Brain Networks In Schizophrenia

Schizophrenia is a severe psychiatric disorder and patients often have abnormal emotional and cognitive functioning.Studies have demonstrated that Schizophrenia shows abnormalities in multi-modal brain network connections,and combining multimodal features can achieve the classification accuracy increased by 90%.Furthermore,reduced functional differentiation has been found in sensory processing and higher-order cognitive functions in schizophrenia based on functional gradients.However,current researches mainly focus on the functional principal gradient.It is unclear how the gradient patterns of multimodal brain networks are altered in schizophrenia.In this dissertation,we focus on multimodal cortical hierarchical changes in schizophrenia and investigate the mechanisms of altered connectivity patterns in schizophrenic patients by analyzing multimodal brain network gradients.In the first study,functional gradients were calculated to exploit the asymmetric alterations of hemispheric gradients in schizophrenia patients.A linear mixed-effects model was used to assess group × hemispheric interaction effects for 17 networks in the cortex and 4 regions in the subcortex,revealing significant interaction effects for schizophrenia in Control network C,Default Mode network A,Default Mode network C,and Temporal Parietal network.The results suggest that cortical functional gradients provide a new perspective for understanding hemispheric asymmetry disorders in schizophrenia.In the second study,abnormal schizophrenia alterations in structural gradients were explored based on the number of white matter fiber bundles.47 significantly different ROIs were found(including 12 FDR-corrected ROIs,mainly in the anterior-posterior central gyrus,paracentral lobule,cingulate gyrus,and hippocampus).Thalamus was found to be related to PANSS general scores.Cingulate gyrus was further identified an opposite abnormal alteration trend in functional and structural gradients.The results suggest that cortical structural gradients provide a new perspective on the disorganization of hierarchical disorders in schizophrenia.In the third study,aberrant morphologically similar gradients alterations in schizophrenia were explored based on JS divergence similarity of cortical thickness.25 significantly different ROIs were found.Only left superior frontal gyrus can be FDRcorrected and correlated with PANSS general scores.Besides,a significant negative correlation between alterations of functional gradients and morphologically similar gradient was found in patients over the whole brain,and results suggest that cortical morphological alterations may compensate for the disorganization of functional gradients at the organizational level.In summary,this paper investigated schizophrenia gradient changes in three modalities: functional,structural,and morphological.The results found that the schizophrenia has different patterns of abnormal alterations in structurally,functionally and morphologically similar brain networks.The results suggest that multimodal gradients can provide a more comprehensive perspective to help understand possible compensatory mechanisms in schizophrenia.