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Schedule-dependent effects of haloperidol and amphetamine: multiple-schedule task shows within-subject effects
1Department of Psychology, Wilson Hall, Vanderbilt University, Nashville, TN 37240, USA.
Pharmacology, Biochemistry, and Behavior
|March 29, 2001
Summary
This study investigated how haloperidol and amphetamine affect rat behavior under different reinforcement schedules. Drug effects varied by dose and schedule, impacting response allocation and maintenance.
Area of Science:
- Behavioral pharmacology
- Neuroscience
- Psychopharmacology
Background:
- Understanding drug effects on behavior requires considering reinforcement schedules.
- Haloperidol (HA) and amphetamine (AM) are known to affect neurotransmitter systems involved in reward and motivation.
Purpose of the Study:
- To examine the dose-dependent effects of haloperidol and amphetamine on operant responding under continuous reinforcement (CRF) and progressive ratio (PR) schedules.
- To determine how these drugs influence the allocation of behavior between different reinforcement contingencies.
Main Methods:
- Rats were trained on a two-lever task with signaled CRF and PR schedules for food reinforcement.
- Dose-response functions for haloperidol (0.0075-0.06 mg/kg) and amphetamine (0.0625-1.00 mg/kg) were determined.
- Behavioral effects were analyzed based on schedule-specific response rates and patterns.
Main Results:
- Haloperidol decreased responding under the PR schedule at lower doses while affecting both CRF and PR at higher doses.
- Amphetamine produced complex effects, increasing responding under CRF while decreasing it under PR within the same session.
- Both drugs demonstrated dose- and schedule-dependent effects on operant behavior.
Conclusions:
- Haloperidol's effects suggest dopaminergic function is crucial for response allocation and maintenance, modulated by reinforcement schedule properties.
- Amphetamine's impact highlights that its effects on positively reinforced behavior are context-dependent and cannot be generalized across all reinforcement schedules.