Conditioned suppression of an operant response using d-amphetamine as the conditioned stimulus

Area of Science:

• Neuroscience
• Behavioral Psychology
• Pharmacology

Background:

• Classical conditioning principles explain how neutral stimuli become associated with biologically significant events.
• Drug states, characterized by unique physiological and subjective effects, have the potential to serve as conditioned stimuli.

Purpose of the Study:

• To investigate the efficacy of a drug state, specifically d-amphetamine, as a conditioned stimulus (CS) in a classical conditioning paradigm.
• To assess whether d-amphetamine paired with inescapable shocks could elicit conditioned suppression of an operant response.

Main Methods:

• A classical conditioning procedure was employed where d-amphetamine injections were paired with inescapable shocks.
• Conditioned suppression was measured by the reduction in a food-reinforced operant response (variable-interval 60 s).
• Effects of d-amphetamine as a CS were compared between paired and unpaired drug-shock exposure groups.

Main Results:

• d-Amphetamine administered during operant sessions, without concurrent shock, effectively acted as a CS, producing conditioned suppression of the food-reinforced response.
• Administration of a novel drug, cocaine hydrochloride, also decreased operant response totals, indicating stimulus generalization.

Conclusions:

• Drug states can serve as effective conditioned stimuli in classical conditioning paradigms.
• The findings suggest that the physiological state induced by a drug can become associated with aversive events, leading to learned behavioral suppression.
• Stimulus generalization occurred, as a novel drug also elicited a similar suppressive effect.