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 the 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 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
we performed a serial circuit disconnection and found that the lOFCàBLA
and BLAàlOFC pathways form a functional circuit regulating the encoding
(lOFCàBLA) and subsequent use (BLAàlOFC) of the stimulus-dependent,
sensory-specific reward memories that are critical for adaptive,
appetitive decision making.