A Multimodal Magnetic Resonance Imaging Study In Patients With First-episode Schizophrenia

Part Ⅰ The topological features of the brain white matter networks in patients with first-episode schizophrenia based on diffusion tensor imagingObjective:In order to explore the pathogenesis of schizophrenia,we investigated the alterations of the global and regional topological characteristics of the brain white matter networks of first-episode patients.Further,we explored brain topological features of white matter networks in schizophrenic patients with different gender.Methods:Seventy-two first-episode schizophrenia patients and thirty age-,sex-,right handedness-,and education-matched healthy controls were recruited to participate this study.They were canned with 3.0T structural magnetic resonance imaging(sMRI)scanner and diffusion tensor imaging(DTI)scanner,the behavioral and clinical data were collected.The fiber assignment by continuous tracking algorithm(FACT)was performed in the whole cerebral cortex to reconstruct white matter tracts.The graph theoretical analysis were used to construct the brain white matter networks.We tried to explore the differences between two groups in the brain topological features from the perspectives of the global network properties and the regional network properties.Results:The brain white matter structural networks had small-world properties in both groups(P=0.70).However,no significant differences were found between the schizophrenia patients group and healthy controls in characteristic path length(P=0.73),clustering coefficient(P=0.96),local efficiency(P=0.46),and global efficiency(P=0.42).Furthermore,the regional efficiency of ninety brain areas in patients group was not found to significantly different with healthy controls.Conclusion:The alterations of the global and regional topological features of the brain white matter networks in first episode schizophrenia patients were not significant.It suggests that the injury of information transmission capacity and interval information integration ability of brain tissue in the early stage of schizophrenia is not significant,The changes in topological features of the brain white matter networks may be not a qualitative factor in the disease.To a certain extent,our results also reflects the schizophrenia is a chronic progressive mental illness.Part Ⅱ Resting-state magnetic resonance imaging in patients with first episode schizophrenia based on the brain reign of Gray matter volume differenceObjective:Schizophrenia is a group of syndromes that contain multiple symptoms and dysfunctions.and there is a significant heterogeneity,which poses a great challenge to etiology research.Kraepelin believes that if the different symptoms dimensions of schizophrenia mixed,it will cover up the heterogeneity of symptoms,and confuse the differences in pathological mechanisms.In this study,to minimize the heterogeneity of symptoms on its possible neurobiological basis,patients with schizophrenia were divided into different subtypes according to different symptom types:paranoid schizophrenia group and non-paranoid schizophrenia group.We tried to combine with structural and resting functional imaging analysis to explore the underlying neurobiology mechanism of different subtypes of schizophrenia,and to further provide individualized treatment for patients with different clinical symptoms.Methods:Participants were 43 first-episode schizophrenic patients comprising of paranoid schizophrenia group(n=25)and non-paranoid schizophrenia group(n=18).Healthy controls(n=30)were matched for age,gender,right handedness and education.Structural magnetic resonance imaging(sMRI),rest-state functional magnetic resonance imaging data,the behavioral and clinical data were collected.VBM(Voxel based morphometry)analysis was used to detect group differences in gray matter volume.Then the resulting brain areas served as regions of interest for further resting-state functional connectivity analysis in all subjects.Results:Compared to healthy controls,the first-episode paranoid schizophrenic patients group(P=0.001)and non-paranoid schizophrenic patients group(P=0.004)shared significantly reduced gray matter volume in left superior frontal gyrus.Significant functional connectivity difference among three groups were the connectivities between the left superior frontal gyrus and right superior frontal gyrus,the left superior frontal gyrus and left middle temporal gyrus,the left superior frontal gyrus and left precuneus.Post-hoc test(LSD)showed that the functional connectivities between the left superior frontal gyrus and right superior frontal gyrus,the left superior frontal gyrus and left precuneus in paranoid schizophrenia patients group were lower than that of the healthy controls and the non-paranoid schizophrenia patients group;the functional connectivity between the left superior frontal gyrus and left middle temporal gyrus in two patient groups were lower than that of the healthy controls.Conclusion:The results suggest that the abnormal connectivity of the left superior frontal gyrus and right superior frontal gyrus may play an important role in the development of paranoid schizophrenia.The abnormal connectivity of the left superior frontal gyrus and left middle temporal gyrus may a key factor in the development of schizophrenia.Furthermore,abnormal functional activity in middle temporal gyrus may be an important neurobiology basis to understand the occurrence of schizophrenia.Part Ⅲ Facial emotion recognition deficits in patients of first-episode schizophrenia:A functional magnetic resonance imaging studyObjective:Previous studies have shown that patients with schizophrenia show abnormalities in brain activation when processing emotional faces.However,most of previous studies recruited chronic schizophrenic patients,and Experiment tasks mostly used block-design,very few studies used of event-related design.Therefore,current study explored whether patients with first-episode schizophrenia in China would show abnormal brain activation during processing of emotional faces with a experiment task of event-related design.Methods:Forty-three patients with schizophrenia,and thirty age-,sex-,right handedness-,and education-matched healthy controls were recruited to participate this study.They were administered 3.0T sMRI scanner and task-state fMRI,the behavioral and clinical data of two group were collected.The accuracy of facial emotion recognition,and the difference in the activation level of brain regions when processing the emotional faces between patients group and healthy controls were examined by two sample t-tests.Results:Significant differences were found between the groups in judging fearful faces and angry,with healthy control groups performed better than the schizophrenia group.During processing of happy faces,schizophrenic patients showed greater activation than healthy controls in the right middle frontal gyrus,bilateral middle cingulate cortex,and right thalamus.During processing of angry faces,patients with schizophrenia showed greater activation than healthy controls in right precuneus and cerebellar vermis.During processing of fearful faces,patients with schizophrenia showed greater activation than healthy controls in left orbital inferior frontal gyrus and left superior temporal gyrus.During processing of neutral faces,patients with schizophrenia showed greater activation than healthy controls in right middle frontal gyrus,right supplementary motor area,right thalamus and cerebellar vermis.Conclusion:Our results showed that patients with first-episode schizophrenia have facial emotion recognition deficits,which supports facial emotion recognition disorder may be a phenotype of schizophrenia.