Integrating anxiety and motivation: Prefrontal mechanisms arbitrating the approach-avoidance conflict

Healthy adaptive behavior requires pursuing goals despite uncertainty. Because approaching any stimulus entails potential risk, threat evaluation and reward pursuit often occur simultaneously, creating competition between defensive and goal-directed drives. This dynamic defines approach-avoidance conflict and reflects two fundamental processes: anxiety and motivation. Here, we treat these two psychological concepts as functional constructs that link neural circuit activity to behavioral output. We define anxiety as heightened arousal driven by potential threat under uncertainty, and motivation as a multi-modal driver that involves allocating effort toward either approaching rewards (approach motivation) or avoiding perceived threat (avoidance motivation). We argue that the circuitry associated with anxiety and motivation features substantial overlap, allowing for a tightly linked system in which anxiety reshapes motivational evaluation by altering how costs, rewards, and action outcomes are computed. Further, arbitration of this conflict depends on top-down control from the medial prefrontal cortex (mPFC), which integrates competing affective and motivational signals to guide behavior. However, sustained elevations in anxiety can dysregulate prefrontal circuits, biasing behavior towards avoidance and contributing to the motivational impairments observed across psychiatric disorders. Importantly, the relationship between anxiety and motivation is non-linear: low to moderate anxiety may facilitate engagement, whereas excessive anxiety promotes avoidance, complicating experimental interpretation. Here, we outline the neural circuits underlying anxiety and motivation and examine how the mPFC coordinates activity across projection-defined circuits linking cell populations within the ventral hippocampus, amygdala, striatum, and others to integrate affective and motivational signals that ultimately bias action selection according to their combined valence.