Does pimozide block the reinforcing effect of brain stimulation?

Area of Science:

• Neuroscience
• Behavioral Pharmacology

Background:

• The medial forebrain bundle (MFB) is crucial for reward processing.
• Neuroleptics can modulate motivated behaviors.

Purpose of the Study:

• To investigate the effects of the neuroleptic pimozide on MFB self-stimulation in rats.
• To determine if pimozide blocks the reinforcing properties of MFB stimulation.

Main Methods:

• Rats were trained to perform tasks (runway, Skinner box) for MFB electrical stimulation.
• Pimozide was administered at doses significantly lower than those causing incapacitation.
• Behavioral performance was assessed before and after drug administration.

Main Results:

• Pimozide induced an extinction-like decline in both runway and Skinner box performance.
• This effect occurred even after pre-exposure to the running wheel and MFB stimulation.
• The decline was task-specific, indicating a specific disruption of the reward pathway.

Conclusions:

• Pimozide effectively blocks the reinforcing effects of MFB electrical stimulation.
• The findings suggest pimozide disrupts reward-related neural circuits at behaviorally relevant doses.