Chronic haloperidol treatment: effects on operant responding and inter-response time

Area of Science:

• Neuroscience
• Pharmacology
• Behavioral Science

Background:

• Haloperidol is a typical antipsychotic.
• Its effects on operant behavior are not fully understood.
• Motor deficits and anhedonia are potential mechanisms of action.

Purpose of the Study:

• To investigate the effects of haloperidol on operant behavior in rats.
• To differentiate between anhedonia and motor deficits as explanations for haloperidol's effects.

Main Methods:

• Male Sprague-Dawley rats were trained on a fixed ratio-40 schedule for food reinforcement.
• Rats received three doses of haloperidol (0.125, 0.25, 0.5 mg/kg) under various treatment regimens (Baseline, Presession, Postsession, Extinction).
• Inter-response times were measured.

Main Results:

• Presession and Extinction treatments significantly decreased earned reinforcements.
• Increased inter-response times correlated with decreased reinforcements.
• Presession treatment, but not Postsession, significantly reduced reinforcements.

Conclusions:

• Chronic presession haloperidol administration impairs operant behavior.
• Results favor an anhedonia interpretation over cumulative motor deficits.
• Concurrent exposure to haloperidol and behavior is critical for observed decrements.