A Combined Single Voxel Magnetic Resonance Imaging Studies In Patients With First-episode Schizophrenia

Objectives: The pathological mechanism of schizophrenia was unclear,some brain imaging studies suggested the ventralmedial prefrontal cortex(vmPFC)maight play an important role in the etiology of schizophrenia.This article wanted to investigate the vmPFC and related network in the etiological of schizophrenia by using functional magnetic resonance imaging(fMRI)and magnetic resonance spectroscopy(MRS).Methods: Twenty two first-episode schizophrenia patients and twenty three healthy controls were enrolled in a cross-sectional case control study.All subjects were interview by MINI and the patients group were assessed mental symptoms by PANSS.Then they were scanned by Siemens 3.0T magnetic resonance system which collects the GABA concentration in ventralmedial prefrontal cortex and the brain blood oxygenation level dependent functional magnetic resonance signals.The magnetic resonance spectroscopy data were preprocessed by LCModel software,the functional magnetic resonance image data were preprocessed by Matlab software package.All data were analyzed by SPSS17.0 software.Results:(1)For schizophrenia patients and healthy control in the vmPFC,the GABA concentration were 2.277±0.544 mM and 1.932±0.315 mM,the GLU concentration were 4.072±2.600 mM and 3.707±1.357 mM,the GLN concentration were 2.776±1.404 mM and 2.293±1.063 mM,the NAA concentration were 4.220±0.793 mM and 4.456±0.809 mM.Significantly higher GABA were found in patients with schizophrenia in the ventralmedial prefrontal cortex as compared to healthy controls(t = 2.615,p = 0.012),the GABA concentration has been found to be positively correlated with age in patients(r = 0.474,p = 0.026).(2)Compared to healthy controls,functional connectivity in the resting state was abnormal in patients.The brain area with decreased functional connectivity included left parahippocampal gyrus,left anterior cingualte cortex,right fusiform gyrus and left supramarginal gyrus.The brain area with increased functional connectivity included right inferior occipital gyrus,left fusiform gyrus,precentral gyrus and left precuneus.Functional connectivity between vmPFC and left parahippocampal gyrus has been found to be positively correlated with general psychiatric score(r =-0.465,p = 0.029).(3)In the health controls,the GABA concentration has been found negatively correlation with functional connectivity between vmPFC and left parahippocampal gyrus(r =-0.415,p = 0.049),the GLN concentration has been found negatively correlation with functional connectivity between vm PFC and left fusiform gyrus(r =-0.556,p = 0.006).The GABA and GLU concentration both has been found positively correlation with left supramarginal gyrus in patients(r = 0.518,p = 0.014 and r = 0.530,p = 0.011).Conclusions: VmPFC maight plays an important role in schizophrenia,the abnormal GABA in vmPFC could affect the functional connectivity(FC)between this region and others,leading to a various of mental symptoms.This research could support the glutamate and GABA hypothesis of schizophrenia.