Resting-state Functional Magnetic Resonance Imaging Study Of Amplitude Of Low Frequency Fluctuation In First-episode Patients With Schizophrenia

ObjectiveIn recent years, resting state functional magnetic resonance imaging (Rs-fMRI) study are mainly using functional connectivity methods in schizophrenia. Many studies consider that schizophrenia was a "dysfunctional" disorder with this method.Functional connectivity is from activity on the time-related abnormal brain regions,which may explain the pathological mechanisms in schizophrenia, but can not directly explain the abnormal spontaneous activity of local brain regions. Low-frequency amplitude method can reflect the abnormal of local brain in resting state. In this study, we compared first-episode schizophrenia patients with healthy control people to study the local brain change in first-episode schizophrenia patients by using the amplitude of low frequency fluctuation (ALFF) and fractional amplitude of low frequency fluctuation (fALFF) methods in resting state, we also excluded the impact of course and drugs.MethodWe used3.0T fMRI to assess the whole brain activity in resting-state from27first-episode, antipsychotic-naive schizophrenia patients(the patient group) diagnosed by Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) and22gender-, age-and years of education matched healthy control groups (the healthy control group).An attending doctor assessed the schizophrenia patients’ positive and negative syndrome scale (PANSS) points during the day of fMRI scanning. For Rs-fMRI data were preprocessed by SPM8software.In our study head movement translation>1mm and rotational movement>1°subjects were excluded. For the preprocessed data were made analysis of amplitude of low frequency fluctuation (ALFF) and fractional amplitude of low frequency fluctuation (fALFF) among all local brain regions under resting state by Rest1.6software. In order to know the change of ALFF and fALFF in all the local brain between the patient group and the healthy control group in resting state, two groups of treatment of ALFF image and fALFF image based on two-sample t test,respectively. On the voxel level, we selected brain regions when single voxel P<0.01and a minimum cluster size>18voxels, then used the AlphaSim corrected, after AlphaSim corrected, when t>2.36, P<0.05,these brain regions were defined as statistically significant difference brain regions.Result1. ALFF results1.1. Compard with the healthy controls group, ALFF significantly higher brain areas in the patient group were premotor area, supplemental motor area and orbitofrontal lobe (P<0.05, Alphaism corrected).1.2. Compard with the healthy controls group,ALFFsignificantly decreased brain areas in the patient group were precuneus, posterior cingulate cortex, medial prefrontal lobe and angular gyrus, the differences were statistically significant (P<0.05, Alphaism corrected).2. fALFF results1.1. Compard with the healthy controls group, fALFF significantly higher brain areas in the patient group was orbitofrontal lobe (P<0.05, Alphaism corrected).1.2. Compard with the healthy controls group, fALFF significantly decreased brain areas in the patient group were precuneus, posterior cingulate cortex, left dorsal lateral prefrontal cortex and left angular gyrus, the differences were statistically significant (P<0.05, Alphaism corrected). Conclusion1.There are abnormal resting state spontaneous activity localized brain in first episode patients with schizophrenia such as premotor area, supplemental motor area, orbitofrontal lobe, posterior cingulate cortex, medial prefrontal lobe, angular gyrus and left dorsal lateral prefrontal cortex.2.1n our study, we both used ALFF and fALFF methods to analyze for the same data, After using the two methods,we found the same abnormalities brain regions at orbitofrontal gyrus, precuneus, posterior cingulate,angular gyrus and left dorsal lateral prefrontal cortex in first-episode schizophrenia patients, these results had a high reliability.3.These abnormal brain regions involve the default mode network and task positive network.4.These abnormal brain regions may help explain the pathogenesis of schizophrenia.