Objective:To investigate the correlation between suicidal behavior and brain default mode network(DMN)activity changes at the resting state in young female suffered from depression. Methods:Twenty-three sex-and age-matched female patients with suicide attempt and depression(SD group)were compared with 10 non-suicidal depressed patients(NSD group)and 31 healthy controls(HC group)in the study. Functional connectivity changes in DMN regions which may associate with suicide behavior were explored by comparing resting-state functional magnetic resonance imaging(rs-f MRI)signals using independent component analysis(ICA)approaches. The correlation between time courses of regions of interests(ROIs)in DMN and six clinical scale scores were conducted.Results:Compared with the healthy controls

all depressed patients showed decreased connectivity in bilateral precuneus

suicidal patients showed increased connectivity in the left middle temporal cortex(-56

-65

15)and left middle occipital gyrus(-45

-70

18)while non-suicidal depressed patients showed increased in bilateral posterior cingulate cortex(PCC)(corrected P<0.05). Compared with non-suicidal patients

suicidal patients showed increased functional connectivity in the left lingual gyrus(-12

-55

3)

the left precuneus(-7

-61

15)and weakened connectivity in bilateral posterior cingulated cortex(corrected P<0.05). Negative correlations between time series of left middle temporal and suicide ideation scale scores(r=-0.643;P=0.045)in non-suicidal depressed patients were revealed. Conclusion:Abnormal brain default network connectivity could emerge in female depressed patients;the suicidal behavior may be associated with abnormal activity in precuneus and posterior cingulate cortex.