A Resting State Functional Magnetic Resonance Imaging Study On Unipolar And Bipolar Depressive Disorder Patients

Objective: To study the features of brain activity and compare their similarities and differencesof patients with unipolar and bipolar depressive disorder, and explore the pathogenesis aboutneurophysiologic of depressive disorder by using regional homogeneity (ReHo) approach offunctional magnetic resonance imaging during resting state.Methods：18unipolar depressive disorder patients,20bipolar depressive disorder patients and16healthy subjects participated in the resting state fMRI scan. Using ReHo approach, toexplore the differences between depressed group and normal group, two-sample t-tests wasperformed on the individual normalized ReHo maps in a voxel-by-voxel manner using SPMsoftware. A combined threshold of α=0.05and minimum cluster size of405were used todetermine significant differences.Results:16unipolar depressive disorder patients,17bipolar depressive disorder patients and16healthy subjects participated in the resting state fMRI scan successfully. The results oftwo-sample t test were displayed, which the combined threshold was t=2.042and K>405:1. The unipolar depressive disorder patients group showed significant ReHo increase in theleft middle occipital lobe, right inferior parietal lobule, right precuneus, left convolution;And significant ReHo decrease in left parahippocampal gyrus, right precentral gyrus, leftpostcentral gyrus, left precentral gyrus and left cingulated.2. The bipolar depressive disorder patients group showed significant ReHo increase in theright insular cortex, left middle frontal gyrus, left precuneus, left occipital lobe, left parietal,left superior frontal gyrus, left thalamus; And significant ReHo decrease in right anteriorlobe of cerebellum, pons, right precentral gyrus, left postcentral gyrus, left inferior frontalgyrus and right cingulate.3. Compared with bipolar depressive disorder patients group, the unipolar depressive disorderpatients group showed significant ReHo decrease in thalamus.Conclusion:1The frontal lobe, parietal lobe and occipital lobe are the same abnormal brain regions ofunipolar and bipolar depressive disorder patients, which suggest that the depressivedisorder episode may be induced of the same brain regions.2. The abnormal brain regions in bipolar depressive disorder patients are most of the structure of the limbic system, cerebellum and brainstem, suggesting that bipolar depressive disorderpatients with limbic system, cerebellum and brain stem injury is more apparent.3. The thalamus is the different brain region between unipolar and bipolar depressive disorderpatients.4. Based on the neural circuit analysis, the occurrence of atypical clinical symptoms ofbipolar depressive disorders may be related to the injured of ventral cortex-lateral limbiccortex-brainstem.