Nonoverlapping Social and Sucrose Reward Representations in the Basolateral Amygdala

Animals must continually evaluate the relative value of social and food rewards to guide adaptive behavior. While both food and social stimuli engage overlapping reward networks, how these reward types are represented within specific nodes of the circuit remains unresolved. The basolateral amygdala (BLA), a region critical for valence and motivational processing, has been implicated in encoding both shared and distinct representations of social and food stimuli. Using in vivo calcium imaging in freely behaving male and female mice performing a two-choice social-sucrose operant task, we examined how individual BLA neurons encode these two different rewards within the same behavioral framework. We found that largely nonoverlapping populations of BLA neurons respond to social and sucrose rewards, revealing distinct representational subspaces for each reward type. Under baseline conditions, both sexes robustly encoded social and sucrose rewards, but water deprivation revealed a pronounced sex difference, shifting representations toward sucrose reward in females. Populations of sucrose reward-responsive neurons in the BLA were selectively sensitive to reward omission. Specifically, sucrose-excited neurons were more strongly modulated by the absence of expected reward than sucrose-inhibited neurons, suggesting a key role for these neurons in signaling reward prediction violations. Together, these findings demonstrate that the BLA encodes social and sucrose rewards through distinct, state-dependent, and functionally heterogeneous neuronal populations, highlighting region-specific strategies for representing reward identity and internal motivational context.