Paraventricular Thalamus Controls Behavior during Motivational Conflict

Decision-making often involves motivational conflict because of the competing demands of approach and avoidance for a common resource: behavior. This conflict must be resolved as a necessary precursor for adaptive behavior. Here we show a role for the paraventricular thalamus (PVT) in behavioral control during motivational conflict. We used Pavlovian counterconditioning in male rats to establish a conditioned stimulus (CS) as a signal for reward (or danger) and then transformed the same CS into a signal for danger (or reward). After such training, the CS controls conflicting appetitive and aversive behaviors. To assess PVT involvement in conflict, we injected an adeno-associated virus (AAV) expressing the genetically encoded Ca t indicator GCaMP and used fiber photometry to record population PVT Ca2+ signals. We show distinct profiles of responsivity across the anterior-posterior axis of PVT during conflict, including an ordinal relationship between posterior PVT CS responses and behavior strength. To study the causal role of PVT in behavioral control during conflict, we injected AAV expressing the inhibitory hM4Di DREADD and determined the effects of chemogenetic PVT inhibition on behavior. We show that chemogenetic inhibition across the anterior-posterior axis of the PVT, but not anterior or posterior PVT alone, disrupts arbitration between appetitive and aversive behaviors when they are in conflict but has no effect when these behaviors are assessed in isolation. Together, our findings identify PVT as central to behavioral control during motivational conflict.