The effect of emotional faces on reward-related probability learning in depressed patients

Existing research indicates that individuals with Major Depressive Disorder (MDD) exhibit a bias toward salient negative stimuli. However, the impact of such biased stimuli on concurrent cognitive and affective processes in individuals with depression remains inadequately understood. This study aimed to investigate the effects of salient environmental stimuli, specifically emotional faces, on reward-associated processes in MDD. Thirty-three patients with recurrent MDD and thirty-two healthy controls (HC) matched for age, sex, and education were included in the study. We used a reward-related associative learning (RRAL) task primed with emotional (happy, sad, neutral) faces to investigate the effect of salient stimuli on reward-related learning and decision-making in functional magnetic resonance imaging (fMRI). Participants were instructed to ignore emotional faces during the task. The fMRI data were analyzed using a full-factorial general linear model (GLM) in Statistical Parametric Mapping (SPM12). In depressed patients, cues primed with sad faces were associated with reduced amygdala activation. However, both HC and MDD group exhibited reduced ventral striatal activity while learning reward-related cues and receiving rewards. The patients'medication usage was not standardized. This study underscores the functional alteration of the amygdala in response to cognitive tasks presented with negative emotionally salient stimuli in the environment of MDD patients. The observed alterations in amygdala activity suggest potential interconnected effects with other regions of the prefrontal cortex. Understanding the intricate neural connections and their disruptions in depression is crucial for unraveling the complex pathophysiology of the disorder. •An event-related card-guessing task to evaluate neural activation during probabilistic reward learning following brief emotional stimulus was used in the present study.•Both MDD and HC groups showed similar behavioral performance in mean by reaction time, accuracy and learning rates.•Emotional faces induce BOLD changes at the right ventral striatum, suggesting strong affective effect of emotional faces even they were presented very briefly.•In sad face condition, MDD patients had shown significantly reduced BOLD signals in both left and right amygdala and right hippocampus compared to healthy controls.•Emotional priming during probabilistic cue period effects BOLD levels in the right striatum and hippocampus at the out