Effects of Limited and Extended Pavlovian Training on Devaluation Sensitivity of Sign- and Goal-Tracking Rats

Area of Science:

• Behavioral neuroscience
• Learning and memory
• Animal models of addiction

Background:

• Individual differences in Pavlovian approach behavior (goal-tracking vs. sign-tracking) predict distinct patterns of outcome devaluation sensitivity.
• Sign-tracking (ST) rats are typically insensitive to outcome devaluation, whereas goal-tracking (GT) rats are sensitive.
• Extended Pavlovian training may alter devaluation sensitivity, particularly in GT rats exhibiting sign-tracking-like behaviors.

Purpose of the Study:

• To investigate how limited versus extended Pavlovian lever autoshaping (PLA) training affects devaluation sensitivity in GT and ST rats.
• To compare sensitivity to satiety-induced versus illness-induced outcome devaluation in ST rats after extended PLA training.
• To explore the translational relevance of behavioral flexibility in devaluation paradigms for understanding addiction vulnerability.

Main Methods:

• Within-subject satiety-induced outcome devaluation procedure in GT and ST rats after limited and extended PLA training.
• Assessment of conditioned responding following devaluation by satiety (pellet devaluation) or illness (lithium chloride injection).
• Comparison of devaluation sensitivity between GT, ST, and intermediate rats across different training durations and devaluation methods.

Main Results:

• GT rats remained sensitive to satiety devaluation irrespective of PLA training duration.
• ST rats, initially insensitive, demonstrated satiety devaluation sensitivity after extended PLA training.
• ST rats showed insensitivity to illness-induced devaluation even after extended training, unlike GT and intermediate rats.

Conclusions:

• Devaluation sensitivity is stable in GT rats across training and devaluation methods.
• Extended training unmasks satiety devaluation sensitivity in ST rats, but not illness-induced devaluation sensitivity.
• Differential behavioral flexibility in response to state-dependent versus inference-based devaluation has implications for addiction research.