Brain Functional Changes Of Resting-State Functional MRI Before And After Electroconvulsive Therapy In Patients With Schizophrenia

BackgroundSchizophrenia is a common psychiatric disorder associated with brain functional abnormalities.To date,electroconvulsive therapy(ECT)has been regarded as the most effective antipsychotic therapy.However,the underlying mechanism by which it exerts therapeutic effect is not fully understood.Resting-state functional magenetic resonance imaging(rs-fMRI)is a new tool to study the effects of brain stimulation interventions,particularly ECT.Therefore,studying cerebral function used rs-fMRI in patients with schizophrenia before and after ECT treatment can enhance understanding of the therapeutic mechanisms of ECT.ObjectivesTo examine alterations of ALFF and functional connectivity in patients with schizophrenia before and after ECT and to explore the antipsychotic mechanism of ECT.MethodsThirty-three patients of schizophrenia treated by ECT were recruited.We collected resting-state functional magnetic resonance imaging before ECT(baseline,time point 1)and then 10-12 h after the eighth ECT sessions(time point 2).Fourty-three matched healthy control subjects just underwent one scan at baseline for comparison purposes.We computed voxel-wise amplitude of low-frequency fluctuation(ALFF)as a measure of regional brain activity.Functional connectivity across brain regions was evaluated using a seed voxel correlation approach analysis and the regions with significant change in ALFF values before and after ECT were extracted as region of interest in order to evaluatefunctional integration in the brain before and after ECT treatment.The fMRI data were processed and analyzed with DPARSF and REST software packages.Results1.ALFF analysisCompared with demographically healthy controls,regional brain activity measured by ALFF was significantly higher in the right inferior parietal louble in patients before ECT(independent two-sample t-test,t=2.566,P=0.012);Compared to the baseline,patients at time point 2 showed decreased ALFF mainly in the right inferior parietal louble,right superior frontal gyrus,left inferior frontal operculum gyrus and right insula following ECT(paired two-sample t-test,P<0.05,corrected with AlphaSim).2.The correlation between changes of ALFF and changes of PANSS scoresReduction in supplementary impulsive aggression symptoms were negatively correlated with decreased ALFF values in the left inferior frontal operculum(r=-0.356,P=0.042);There was a negative correlation between decreased ALFF values in the right superior frontal gyrus following ECT and baseline PANSS total scores(r=-0.345,P=0.049);There was a negative correlation between decreased ALFF values in the right superior frontal gyrus following ECT and baseline PANSS scores in the positive,negative,and general subscales(r=-0.366,P= 0.036);There was a negative correlation between decreased ALFF values in the right superior frontal gyrus following ECT and baseline PANSS negative symptom scores(r=-0.413,P= 0.017);There was a positive correlation between decreased ALFF values in the left inferior frontal operculum following ECT and baseline PANSS supplementary impulsive aggression scores(r= 0.347,P= 0.048);The positive correlation between decreased ALFF in the right superior frontal gyrus and reduction in negative symptoms was significant in critical state of statistics(r= 0.339,P=0.054);There was no significant correlation between the changes of PANSS total scores and the changed ALFF values in the right insula,right inferior parietal louble,left inferior frontal operculum and the right superior frontal gyrus(r= 0.043,P= 0.812;r=-0.066,P=0.717;r=-0.177,P= 0.324;r= 0.221,P= 0.216).3.Functional connectivity analysisCompared to the baseline,functional connectivity of the right insula increased in the right cerebelum and bilateral calcarine cortex following ECT;functional connectivity of the right inferior parietal louble increased in the right calcarine cortex and bilateral postcentral gyrus following ECT;functional connectivity of the left inferior frontal operculum gyrus increased in the left rectus,left inferior temporal gyrus and right middle frontal gyrus following ECT;functional connectivity of the right superior frontal gyrus increased in the right inferior occipital gyrus following ECT(paired two-sample t-test,P<0.05,corrected with AlphaSim).ConclusionsSchizophrenia is related with the functional activity deficit of the right inferior parietal lobule;ECT may elicit an unspecific inhibitory effect on neural activity;Modulating dysfunctional spontaneous neural activity and an increase in resting state functional connectivity between brain regions may contribute to the therapeutic effect of ECT for patients of schizophrenia.