| Background and purposeSchizophrenia is a common complex mental illness that can cause serious consequences,the etiology of which unknown and diverse.In the past,schizophrenia was only always considered to be a complex psychological disorder.With the development of various neuroimaging techniques,abnormalities in brain structure and function of schizophrenic patients have been gradually reported.However,the research results are still diverse and lack of consistency.Schizophrenia always shows complex symptoms,including hallucinations,delusions,social withdrawal and cognitive dysfunction.Auditory hallucination is one of the most common symptoms of schizophrenia,which occurs in 70%-80%patients and brings great physical and psychological pain to the patients,as well as huge economic burden and security risks to the patients’families and society.Previous studies have suggested that the occurrence of auditory hallucination is related to various factors,such as brain structure,brain functional network,cerebral blood flow and neurocyte metabolism abnormality.However,the mechanism of auditory hallucinations is still unknown,so revealing the neural mechanism of auditory hallucinations not only can reduce the differences in research results brought about by the heterogeneity of schizophrenia,but also contribute to find objective biological markers for the development of schizophrenia,which provides theoretical support for the treatment of schizophrenia.The purpose of this study was to investigate brain gray matter structure and resting state cerebral blood flow differential changes in the first-episode schizophrenia patients with and without auditory hallucination symptoms,and their correlation with various psychiatric symptoms,and then explore the neuroimaging mechanisms of auditory hallucination.Materials and methods1.The research platform for this study was GE Discovery 750 3.0T MR scanner from the United States.The study subjects were 93 cases of untreated first-episode schizophrenia patients and 61cases of healthy controls who were matched by age,gender and the years of education.All of the subjects underwent conventional MRI scanning,3D high-resolution structural imaging and 3D pseudo-continuous arterial spin labeling(3D-pcASL)sequence scanning.2.The pre-processing platform of 3D high resolution structure images and3D-pcASL images is SPM8 software based on Matlab.The 3D high-resolution structural images preprocessing includes data format conversion,segmentation of three brain structures,registration and spatial standardization,resampling,and spatial smoothing(8×8×8 mm~3)to obtain brain gray matter images that can be used for statistics and the gray matter volume(GMV)of the subjects.The 3D-pcASL images preprocessing includes data format conversion,spatial one-step registration,normalization,and spatial smoothing(8×8×8 mm~3)to obtain cerebral blood flow(CBF)images that can be used for statistics.3.The statistical analysis was proceeded by SPM8 software based on Matlab platform.One-way ANOVA was used to compare GMV and CBF among the auditory group,the non-auditory group and the control group.The results were saved as template mask,and then the independent sample t test was used for post-mortem analysis to compare the differences between two groups.We removed the influence of gender,age,and years of education as covariates by SPSS 22.0 software.A partial correlation analysis was performed to investigate the association between the psychiatric symptoms scores and the significant statistics results of GMV and CBF.The test level of each statistical analysis process wasα=0.05.Results1.Clinical data analysis showed that there was no statistical difference between the auditory group,the non-auditory group,and the control group in age,gender,and education years(P>0.05).There was a significant difference in positive symptom scores and hallucination scores between auditory and non-auditory groups(P<0.01).2.One-way ANOVA analysis showed that different GMV brain regions among three groups were located in left occipital lobe,bilateral lenticular nucleus,left parahippocampal gyrus,right middle frontal gyrus,right cerebellar posterior lobe and right anterior cerebellar lobe(P<0.001,cluster size>50voxels).3.Compared with the control group,the GMV of the left occipital lobe of the auditory audition group decreased,and GMV of the right central frontal gyri of the non-auditory group decreased(P<0.001,cluster size>17voxels).Compared with the non-auditory group,GMV of the right cerebellum and left occipital lobe in the auditory group decreased(P<0.001,cluster size>82voxels).4.The different CBF brain region amng the auditory hallucinatory group,the non-auditory group and the control group were:the left temporal gyrus,the left temporal gyrus,the bilateral bean nucleus,the bilateral occipital lobe,the bilateral frontal lobe and the right parietal lobe(P<0.001,cluster size>100voxels).5.Compared with the control group,CBF in the left middle temporal gyrus and bilateral lentiform nucleus increased significantly(P<0.001,cluster size>363 voxels)in the auditory group and non-auditory group,and the right occipital CBF reduced in the auditory group(P<0.001,cluster size>120voxels).6.The correlation analysis found that the CBF value of the left lentiform nucleus in the auditory group was negatively correlated with the auditory hallucination score(r=-0.29,P=0.045).There was a positive correlation between the CBF value of the right occipital lobe and auditory hallucination score in the auditory group(r=0.42,P=0.004).The CBF value of the left lentiform nucleus of auditory group was positively related to negative symptoms rating scale(r=0.33,P=0.33).Conclusions1.In the first-episode schizophrenia patients with hallucinogenic symptoms,brain structures and cerebral blood flow abnormalities in multiple brain regions are detected,and changes of cerebral blood flow in some brain regions are associated with psychiatric symptoms.2.The abnormal gray matter volume in the cerebellum may be the pathophysiological basis of auditory hallucination and cognitive dysfunction in schizophrenia,supporting the neurocognitive hypothesis of auditory hallucination to some extent.3.The increase of CBF in bilateral lenticular nucleus and right middle temporal gyrus of schizophrenia patients with auditory hallucination indirectly indicates that hyperactivity of dopamine and dysfunction of auditory cortex may be an important pathophysiological mechanism of auditory hallucinations in schizophrenia patients. |
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