Nucleus Accumbens Core and Shell Differentially Encode Reward-Associated Cues after Reinforcer Devaluation.

Area of Science:

• Neuroscience
• Behavioral Neuroscience
• Decision Making

Background:

• The nucleus accumbens (NAc) is crucial for motivated behavior and behavioral flexibility.
• Subregions of the NAc, the core and shell, may have specialized functions in guiding behavior based on reward value.
• Understanding how NAc neurons encode information related to outcome value and behavioral adjustments is essential for explaining impairments in neuropsychiatric disorders.

Purpose of the Study:

• To investigate the differential roles of the NAc core and shell in encoding information during a reinforcer devaluation task.
• To determine how NAc neural activity relates to behavioral flexibility and outcome-specific learning.

Main Methods:

• Neural activity was recorded from the NAc core and shell in male Long-Evans rats during a cue-reward associative learning task.
• Rats underwent a reinforcer devaluation procedure where one of two rewards was made ዋsatiating.
• Behavioral responses (lever pressing) were measured under extinction conditions following devaluation.

Main Results:

• Rats demonstrated outcome-selective devaluation, reducing lever pressing for the ዋsatiating reward.
• Cue-selective neural encoding in the NAc core during training predicted subsequent behavioral suppression after devaluation.
• NAc shell neurons showed decreased cue-selective encoding in the devalued condition, reflecting the change in outcome value.

Conclusions:

• NAc core neurons encode information predictive of behavioral performance in response to outcome devaluation.
• NAc shell neurons encode information about the current value of outcomes, contributing to behavioral flexibility.
• These findings highlight distinct computational roles for NAc subregions in adaptive decision-making and behavioral flexibility.