Emotional valence modulates brain functional abnormalities in depression: evidence from a meta-analysis of fMRI studies

Models describing the neural correlates of biased emotion processing in depression have focused on increased activation of anterior cingulate and amygdala and decreased activation of striatum and dorsolateral prefrontal cortex. However, neuroimaging studies investigating emotion processing in depression have reported inconsistent results. This meta-analysis integrates these findings and examines whether emotional valence modulates such abnormalities. A systematic literature search identified 26 whole-brain and 18 region-of-interest studies. Peak coordinates and effect sizes were combined in an innovative parametric meta-analysis. Opposing effects were observed in the amygdala, striatum, parahippocampal, cerebellar, fusiform and anterior cingulate cortex, with depressed subjects displaying hyperactivation for negative stimuli and hypoactivation for positive stimuli. Anterior cingulate activity was also modulated by facial versus non-facial stimuli, in addition to emotional valence. Depressed subjects also showed reduced activity in left dorsolateral prefrontal cortex for negative stimuli and increased activity in orbitofrontal cortex for positive stimuli. Emotional valence is a moderator of neural abnormalities in depression, and therefore a critical feature to consider in models of emotional dysfunction in depression.