How distributed subcortical integration of reward and threat may inform subsequent approach-avoidance decisions.

Healthy and successful living involves carefully navigating rewarding and threatening situations by balancing approach and avoidance behaviours. Excessive avoidance to evade potential threats often leads to forfeiting potential rewards. However, little is known about how reward and threat information is integrated neurally to inform approach or avoidance decisions. In this preregistered study, participants (N_behaviour=31, 17F; N_MRI=28, 15F) made approach-avoidance decisions under varying reward (monetary gains) and threat (electrical stimulations) prospects during functional MRI scanning. In contrast to theorized parallel subcortical processing of reward and threat information before cortical integration, Bayesian Multivariate Multilevel analyses revealed subcortical reward and threat integration prior to indicating approach-avoidance decisions. This integration occurred in the ventral striatum, thalamus, and bed nucleus of the stria terminalis (BNST). When reward was low, risk-diminishing avoidance decisions dominated, which was linked to more positive tracking of threat magnitude prior to indicating avoidance than approach decisions across these regions. In contrast, the amygdala exhibited dual sensitivity to reward and threat. While anticipating outcomes of risky approach decisions, we observed positive tracking of threat magnitude within the salience network (dorsal anterior cingulate cortex, thalamus, periaqueductal gray, BNST). Conversely, after risk-diminishing avoidance, characterized by reduced reward prospects, we observed more negative tracking of reward magnitude in the ventromedial prefrontal cortex and ventral striatum. These findings shed light on the temporal dynamics of approach-avoidance decision-making. Importantly, they demonstrate the role of subcortical integration of reward and threat information in balancing approach and avoidance, challenging theories positing predominantly separate subcortical processing prior to cortical integration.Significance statement When deciding whether to approach or avoid situations, our decision-making involves balancing potential rewards and threats. Widespread theories of decision-making in humans propose parallel processing of reward and threat information in subcortical regions, followed by cortical integration. Challenging these notions, we found evidence for dual and integrated processing of reward and threat in subcortical regions during decision-making. In contrast, after decision-making, we observed the expected parallel processing while anticipating decision outcomes. These findings advance our understanding of approach-avoidance decision-making processes, opposing traditional views that segregate brain regions as predominantly reward-sensitive or threat-sensitive, thereby paving the way for a more nuanced perspective that takes into account the stage of decision-making.