A dual-pathway architecture for stress to disrupt agency and promote habit

Abstract

Chronic stress can change how we learn and, thus, how we make decisions1–5. Here we investigated the neuronal circuit mechanisms that enable this. Using a multifaceted systems neuroscience approach in male and female mice, we reveal a dual-pathway, amygdala–striatal neuronal circuit architecture by which a recent history of chronic stress disrupts the action–outcome learning underlying adaptive agency and promotes the formation of inflexible habits. We found that the projection from the basolateral amygdala to the dorsomedial striatum is activated by rewarding events to support the action–outcome learning needed for flexible, goal-directed decision-making. Chronic stress attenuates this to disrupt action–outcome learning and, therefore, agency. Conversely, the projection from the central amygdala to the dorsomedial striatum mediates habit formation. Following stress, this pathway is progressively recruited to learning to promote the premature formation of inflexible habits. Thus, stress exerts opposing effects on two amygdala–striatal pathways to disrupt agency and promote habit. These data provide neuronal circuit insights into how chronic stress shapes learning and decision-making, and help understanding of how stress can lead to the disrupted decision-making and pathological habits that characterize substance use disorders and mental health conditions. Adaptive decision-making often requires an understanding of our agency in a situation; however, chronic stress can disrupt agency and promote inflexible, habitual behaviour by turning off a brain pathway needed for agency and activating one that promotes habit.