A bidirectional corticoamygdala circuit for the encoding and retrieval of detailed reward memories

Adaptive reward-related decision making often requires accurate and detailed representation of potential available rewards. Environmental reward-predictive stimuli can facilitate these representations, allowing one to infer which specific rewards might be available and choose accordingly. This process relies on encoded relationships between the cues and the sensory-specific details of the reward they predict. Here we interrogated the function of the basolateral amygdala (BLA) and its interaction with the lateral orbitofrontal cortex (lOFC) in the ability to learn such stimulus-outcome associations and use these memories to guide decision making. Using optical recording and inhibition approaches, Pavlovian cue-reward conditioning, and an outcome-selective Pavlovian-to-instrumental transfer (PIT) test in male rats, we found that the BLA is robustly activated at the time of stimulus-outcome learning and that this activity is necessary for sensory-specific stimulus-outcome memories to be encoded, so that they can subsequently influence reward choices. Direct input from the lOFC was found to support the BLA in this function. Based on prior work, activity in BLA projections back to the lOFC was known to support the use of stimulus-outcome memories to influence decision making. By multiplexing optogenetic and chemogenetic inhibition to perform a serial circuit disconnection, we found that activity in lOFC[->]BLA projections regulates the encoding of the same components of the stimulus-outcome memory that are later used to allow cues to guide choice via activity in BLA[->]lOFC projections. Thus, the lOFC[->]BLA[->]lOFC circuit regulates the encoding (lOFC[->]BLA) and subsequent use (BLA[->]lOFC) of the stimulus-dependent, sensory-specific reward memories that are critical for adaptive, appetitive decision making.