Stimulus and subject control of schedule-induced drinking

Area of Science:

• Behavioral neuroscience
• Animal behavior
• Operant conditioning

Background:

• Schedule-induced polydipsia is a phenomenon where excessive drinking occurs in animals under specific operant conditioning schedules.
• Understanding the factors influencing schedule-induced drinking is crucial for comprehending behavioral regulation and addiction models.

Purpose of the Study:

• To investigate the relationship between reinforcement magnitude and schedule-induced drinking.
• To examine the effect of extinction interval duration and response dependency on schedule-induced drinking.

Main Methods:

• Three food-deprived rats were trained on fixed-ratio schedules (FR1 or FR2) with varying reinforcer amounts (1-21 pellets).
• Reinforcement periods alternated with extinction intervals, during which drinking behavior was recorded.
• Extinction intervals were manipulated in terms of duration and response dependency.

Main Results:

• Schedule-induced drinking was primarily observed at the onset of extinction intervals.
• Drink durations were significantly longer following larger reinforcer meals (21 pellets) compared to smaller ones (1-9 pellets).
• Response-dependent termination of extinction intervals reduced drinking, with minimal drinking observed only after introducing minimum extinction intervals of 15-60 seconds.

Conclusions:

• Reinforcement magnitude influences the duration of schedule-induced drinking.
• The onset of extinction periods is a critical time for schedule-induced drinking.
• Response-dependent extinction intervals can suppress schedule-induced polydipsia, suggesting a role for behavioral control.