INTERACTIONS BETWEEN APPETITIVE AND AVERSIVE PROCESSING DURING PERCEPTION AND ATTENTION
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Although understanding brain mechanisms of appetitive-aversive interactions is relevant to our daily lives and has potential clinical relevance, our knowledge about these brain mechanisms is rudimentary. To address this gap in the literature, we conducted two functional MRI studies that investigated appetitive-aversive interactions during perception and attention in healthy adult human brain. In the first study, we probed how potential reward signaled by advance cues altered aversive distractor processing during a subsequent visual task. Behaviorally, the deleterious influence of aversive stimuli on task performance was reduced during the reward compared to no-reward condition. In the brain, at the task phase, paralleling the observed behavioral pattern, significant interactions were observed in the anterior insula and dorsal anterior cingulate cortex, such that responses during the negative (vs. neutral) condition were reduced during the reward compared to no-reward condition. Notably, negative distractor processing in the amygdala appeared to be independent of the reward manipulation. During the initial cue phase, we observed increased reward-related responses in the ventral striatum, which were correlated with behavioral interference scores at the subsequent task phase, revealing that participants with increased reward-related responses exhibited a greater behavioral benefit of reward in reducing the adverse effect of negative images. Furthermore, the ventral striatum exhibited stronger functional connectivity with fronto-parietal regions important for attentional control. These findings contribute to the understanding of how potential reward influences attentional control and reduces negative distractor processing in the human brain. In the second study, we investigated brain mechanisms underlying the joint processing of positive and negative emotional information during a passive viewing task. Specifically we focused on probing the pattern of appetitive-aversive interactions in brain regions sensitive to the valence and salience of emotional stimuli. In a subset of regions that were sensitive to stimulus valence, competitive interaction patterns were observed. Notably, in other valence-coding regions such as the ventro-medial prefrontal cortex no evidence for competitive interactions was detected. Conversely, in regions sensitive to salience, cooperative interaction patterns were observed. The findings of competitive and cooperative type interactions supported contextual modulation of emotional processing in the human brain.