Résumé
Objective@#To investigate the changes of brain activity in adolescents with first-episode major depressive disorder (MDD) and its significance.@*Methods@#Totally 42 first-episode MDD patients with suicidal ideation (SU group), 17 MDD patients without suicidal ideation (NSU group) and 29 healthy controls (HC group) were examined by psychological assessment and resting-state functional magnetic resonance imaging (fMRI). The differences of brain functional activities between the three groups were compared by amplitude of low frequency fluctuation(ALFF). The relationship between the difference of zALFF value in brain regions and the severity of depression, intensity of suicidal ideation were further analyzed.@*Results@#The zALFF values in the left hippocampus(MNI: x=-21, y=-33, z=0) and left Frontal_Sup_Medial(MNI: x=3, y=33, z=63) of the three groups were significantly abnormal (P<0.001, k>20, uncorrected). The results of Post-hoc test showed that the zALFF value of left hippocampus increased significantly (F=28.931) and decreased significantly in left Frontal_Sup_Medial(F=16.648)in SU group , compared with NSU group and HC group(P<0.001, Bonferroni correction). There was no significant difference in zALFF value between HC group and NSU group(P>0.05). In SU group, the zALFF values of left hippocampus and left Frontal_Sup_Medial were not correlated with total scores of HAMD-24(r=-0.214, -0.103) and suicide ideation intensity factor scores(r=0.115, -0.055)(P>0.05).@*Conclusion@#Abnormal autonomic nervous activity exists in left hippocampus and left Frontal_Sup_Medial in adolescent MDD patients with suicidal ideation, which may be the neurological basis and biological index of suicidal ideation.