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The impact of D-amphetamine and SCH23390 on behavioral momentum of food seeking and reinstatement in rats

Although the environmental determinants of context-specific behavioral persistence have been extensively studied within behavioral momentum theory, little is known about the neurobiological determinants. The present experiment assessed the impact of indirect dopamine agonism with D-amphetamine or dopamine D1 receptor antagonism with SCH23390 on context-specific persistence of behavior. Two groups of rats were trained to make operant responses for equal rates of food delivery in two alternating contexts arranged across sessions. Following baseline, rats received either drug (D-amphetamine or SCH23390) or saline injections before each context. Resistance to extinction and reinstatement in each context were subsequently tested in the absence of drug. Previous exposure to D-amphetamine increased resistance to extinction and reinstatement of behavior, whereas SCH23390 had little impact on resistance to extinction and enhanced reinstatement in the saline context. Quantitative analyses based on behavioral momentum theory suggested that previous treatment with D-amphetamine within a stimulus context may have resulted in a shift to more habitual stimulus-driven behavior that was impacted less by reinforcer omission during subsequent extinction. These results suggest that the persistence of behavior is greater in a context associated with dopamine receptor agonism and that the activity at D1 receptors may differentially modulate extinction and reinstatement performance. These findings may serve as a starting point for future examination and integration of the biological and environmental determinants of behavioral persistence within the framework of behavioral momentum theory.