Ventral pallidum and amygdala cooperate to restrain reward approach under threat

Abstract

Foraging decisions involve assessing potential risks and prioritizing food sources, which can be difficult when confronted with changing and conflicting circumstances. A crucial aspect of this decision-making process is the ability to actively overcome defensive reactions to threats and focus on achieving specific goals. The ventral pallidum (VP) and basolateral amygdala (BLA) are two brain regions that play key roles in regulating behavior motivated by either rewards or threats. However, it is unclear whether these regions are necessary in decision-making processes involving competing motivational drives during conflict. Our aim was to investigate the requirements of the VP and BLA for foraging choices in conflicts involving overcoming fear. Here, we used a novel foraging task and pharmacological techniques to inactivate either the VP or BLA, or to disconnect these brain regions before conducting a conflict test in male rats. Our findings showed that BLA is necessary for making risky choices during conflicts, whereas VP is necessary for invigorating the drive to obtain food, regardless of the presence of conflict. Importantly, our research revealed that the connection between VP and BLA is critical in limiting risk behaviors when searching for food requires effort in conflict situations. This study provides a new perspective on the collaborative function of VP and BLA in driving behavior, aimed at achieving goals in the face of dangers.Significance Statement While searching for food, animals must also be cautious about dangers. This study aimed to investigate how two subcortical brain regions, the ventral pallidum and basolateral amygdala, help individuals make optimal decisions in such conflicting situations. Using a novel task and drugs to silence these regions, we observed how rats made choices. Our findings show that the ventral pallidum drives the effort required to obtain food, whereas the basolateral amygdala triggers caution around dangers. Notably, we revealed that cooperation between these regions prevents animals from taking excessive risks when foraging food involves facing threats. Gaining an understanding of how the brain prioritizes caution over reward could aid in the treatment of mental disorders.