A Study Of The Spontaneous Neural Activity Based On Resting-state Fractional Amplitude Of Low-frequency Fluctuation In Patients With Postpartum Depression

Objective: Postpartum depression(PPD)is a kind of emotional disorder disease,and it is also the most common complication of childbirth,which has a serious impact on mothers,children and families.PPD patients even tend to commit suicide or infanticide.With the opening of the two-child policy in China,the incidence of PPD is also increasing,but PPD has not been fully diagnosed and studied in clinical and experimental studies.Therefore,it is imperative to understand the underlying neural mechanisms of PPD.Blood oxygen level dependence(BOLD)is a noninvasive form of functional magnetic resonance imaging(fMRI)that evaluates neural activity.And the fractional amplitude of low frequency amplitude(fALFF)can reflect the low frequency amplitude of each voxel in the brain and directly determine the brain area of abnormal activity.Therefore,in this study,fMRI was used to investigate the characteristics of brain spontaneous nerve activity in patients with PPD under fractional amplitude of fALFF by resting-state fMRI,and explored its possible pathogenesis.Methods: The resting-state fMRI data of the subjects in each group were collected with the SIEMENS MAGNETOM Verio Dot 3.0T MRI scanner.There were 23 postpartum depression patients(PPD group),28 healthy postpartum women(HPW group)whose age,education and postpartum time were matched and 20 women with major depressive disorder(MDD group)whose age and education were matched.The fALFF technology was used to process the images of each group,and the correlations between the Edinburgh Postnatal Depression Scale(EPDS)score and the fALFF values which were extracted from the different regions of PPD group and HPW group were analyzed.Results:(1)Compared with HPW group,fALFF values of left posterior cingulate gyrus,left precuneus,left middle occipital gyrus,left inferior occipital gyrus and right calcarine in PPD group increased,and fALFF values of right orbital inferior frontal gyrus,right insula,right olfactory cortex and right hippocampus decreased(AlphaSim correction,Clusters>25,P < 0.05).In addition,compared with the HPW group,the brain regions with increased fALFF values in the PPD group were mainly located in the left hemisphere,while the decreased brain regions were concentrated in the right hemisphere.(2)Compared with the MDD group,fALFF values in the right lingual gyrus and cerebellum in the PPD group increased,while significantly decreased in the right dorsolateral prefrontal cortex,right precuneus,left superior parietal gyrus,left angular gyrus,right medial and para-cingulate gyrus and right inferior temporal gyrus(AlphaSim correction,Clusters>30,P < 0.05).(3)The fALFF value in the right orbital inferior frontal gyrus of PPD group was negatively correlated with their EPDS score(r =-0.53,P =0.01).Conclusion:(1)Compared with the HPW group,brain regions with reduced fALFF values in the PPD group are mainly located in the limbic system related to negative emotion regulation and memory function,while the brain regions with increased fALFF values in the PPD group are mainly located in the default mode network(DMN)and occipital cortex related to episodic memory and cognitive function,which suggest that there is abnormal spontaneous neural activity in the brain regions associated with emotion and cognition in patients with PPD in resting state,and that abnormal neuronal activity in patients with PPD may be lateral.(2)Compared with the MDD group,fALFF values of the frontotemporal lobe and DMN,which are closely related to cognitive function,were decreased in the PPD group,and fALFF values of the cerebellum and lingual gyrus,which are related to emotional regulation,were increased.Although both PPD and MDD patients have abnormal changes in neural activity related to emotional and cognitive functions,the fALFF expression of PPD is not completely consistent with that of MDD patients,and PPD may have its characteristic neurological changes.(3)The fALFF value of the right orbital inferior frontal gyrus in patients with PPD is closely related to the severity of depression,and its change of neural activity may be an objective indicator of the degree of depression in PPD patients.