Objective To analyze the differences of brain activity between first-episode untreated depressive patients with and without suicidal ideation(SI),and its correlations with clinical characteristics.Methods A total of 40 major depressive disorder(MDD)patients with SI(MDD+SI group),40 patients without SI MDD(MDD+NSI group),and 40 healthy controls(HC)(HC group)were enrolled.The 17-item Hamilton depression scale(HAMD-17)and Beck scale for suicide ideation(BSI)were used to assess the severity of depression and SI,respectively.MRI data were collected.The values of fractional amplitude of low-frequency fluctuation(fALFF)were calculated.Results(1)Compared with the HC group,the MDD+NSI group showed decreases in the fALFF val-ues of the default network and attention network.The fALFF values of the attention network in the MDD+SI group showed decreases.Compared with the MDD+NSI group,the MDD+SI group showed decreases in the fALFF values of the attention network.(2)The fALFF values in the left middle frontal gyrus were negatively correlated with the total score of HAMD-17(r=-0.55;P<0.001)in the MDD+NSI group,while the fALFF values in the left middle frontal gyrus were negatively correlated with the total score of HAMD-17(r=-0.53;P<0.001)and the total score of BSI(r=-0.51;P<0.001)in the MDD+SI group.(3)The optimal critical value of fALFF value in left middle frontal gyrus for predicting SI occurrence in MDD patients was-0.039,area under the curve(AUC)was 0.76,sensitivity was 0.63,and specificity was 0.80.Conclusion The decreased local activity intensity in the left middle frontal gyrus of the brain might be the central mechanism for the occurrence of SI in MDD patients.In addition,the left middle frontal gyrus might have certain value in identifying SI and predicting the severity of SI.

Objective To analyze the differences of brain activity between first-episode untreated depressive patients with and without suicidal ideation(SI),and its correlations with clinical characteristics.Methods A total of 40 major depressive disorder(MDD)patients with SI(MDD+SI group),40 patients without SI MDD(MDD+NSI group),and 40 healthy controls(HC)(HC group)were enrolled.The 17-item Hamilton depression scale(HAMD-17)and Beck scale for suicide ideation(BSI)were used to assess the severity of depression and SI,respectively.MRI data were collected.The values of fractional amplitude of low-frequency fluctuation(fALFF)were calculated.Results(1)Compared with the HC group,the MDD+NSI group showed decreases in the fALFF val-ues of the default network and attention network.The fALFF values of the attention network in the MDD+SI group showed decreases.Compared with the MDD+NSI group,the MDD+SI group showed decreases in the fALFF values of the attention network.(2)The fALFF values in the left middle frontal gyrus were negatively correlated with the total score of HAMD-17(r=-0.55;P<0.001)in the MDD+NSI group,while the fALFF values in the left middle frontal gyrus were negatively correlated with the total score of HAMD-17(r=-0.53;P<0.001)and the total score of BSI(r=-0.51;P<0.001)in the MDD+SI group.(3)The optimal critical value of fALFF value in left middle frontal gyrus for predicting SI occurrence in MDD patients was-0.039,area under the curve(AUC)was 0.76,sensitivity was 0.63,and specificity was 0.80.Conclusion The decreased local activity intensity in the left middle frontal gyrus of the brain might be the central mechanism for the occurrence of SI in MDD patients.In addition,the left middle frontal gyrus might have certain value in identifying SI and predicting the severity of SI.

Objective To explore the differences of regional homogeneity(ReHo)between overweight and normal weight male patients with type 2 diabetes mellitus(T2DM)during rest and their correlations with clinical features.Methods Twenty-five untreated male overweight T2DM(OW-T2DM)patients,25 untreated male normal weight T2DM(NW-T2DM)patients and 25 healthy controls(HC)were enrolled.The brain structure and resting-state functional magnetic resonance imaging(rs-fMRI)data were collected from all subjects.The brain structure and rs-fMRI data were preprocessed,and ReHo values of all brain regions were calculated for all subjects.ReHo values were compared among three groups and between groups respectively via the methods of one-way analysis of variance and two-sample t-test.To address the problem of multiple comparisons,the method of AlphaSim was performed(the threshold was set at P<0.005,the number of voxel clusters was>12).In addition,Pearson correlation analysis was performed to explore the relationships between ReHo values of the abnormal brain regions and clinical features in patients.Results(1)The brain regions showed differences of ReHo values among three groups were mainly distributed in the right hemisphere,including the superior parietal gyrus,superior marginal gyrus and superior occipital gyrus;(2)Compared with HC,NW-T2DM patients showed significantly decreased ReHo values in the right medial superior frontal gyrus,right middle cingulate gyrus and left anterior cingulate gyrus;(3)Compared with HC,OW-T2DM patients showed significantly decreased ReHo values in the bilateral postcentral gyrus and bilateral middle cingulate gyrus;(4)Compared with NW-T2DM patients,OW-T2DM patients showed significantly decreased ReHo values in the right superior parietal gyrus,right superior occipital gyrus and left cuneus;(5)ReHo values of the right medial superior frontal gyrus and right superior parietal gyrus were negatively correlated with hemoglobinA1c(HbA1c)level and body mass index(BMI),respectively,in all patients.Conclusion The occurrence of T2DM in male patients may lead to the declined activity of brain regions located in the default mode network(DMN),while overweight may further lead to decreased brain activity within the attention and visual recognition network in male T2DM patients.