Neural Divergence between Individuals with and without Minor Depression during Dynamic Emotion Processing: A Movie-fMRI Study

Abstract Research on the neuropathological mechanisms underlying minor depression (MD), particularly in individuals with a history of recurrent minor depressive episodes, is very limited. This study focuses on the abnormality in processing real-life emotional stimuli among MD. Thirty-two individuals with MD and thirty-one normal controls (NC) were recruited and underwent comprehensive clinical interview, cognitive assessment, and magnetic resonance imaging (MRI) scans. During functional MRI scanning, subjects watched positive, negative, and neutral emotional movie clips. We used the inter-subject correlation and inter-subject functional connectivity analysis to investigate the neural differentiation between MD and NC during film viewing. The relationships between neural differentiation, symptom severity, and psychological resilience were analysed. We found that neural differentiations between MD and NC in the post cingulate cortex (PCC) and precuneus (PCUN) were consistent across three emotional conditions. Notably, the similarity of neural responses in the PCC and PCUN with NC but not MD was negatively correlated with depressive symptoms. Furthermore, this neural similarity mediated the relationship between psychological resilience and depression severity. Our findings support that the PCC and PCUN, two core areas of the default mode network, play a critical role in MD’s emotion processing deficit.