Concurrent intracranial self-stimulation and amphetamine self-administration in rats

Area of Science:

• Neuroscience
• Behavioral Pharmacology
• Psychopharmacology

Background:

• Concurrent access to multiple reinforcers is common in real-world scenarios.
• Understanding how animals respond to combined drug and brain stimulation rewards is crucial for addiction research.

Purpose of the Study:

• To investigate the effects of concurrent access to intravenous amphetamine and brain stimulation on rat behavior.
• To determine if amphetamine-induced behaviors interfere with lever pressing for brain stimulation.

Main Methods:

• Rats were trained to press levers for intravenous amphetamine and/or brain stimulation in a two-lever testing chamber.
• Response rates for each reinforcer were compared under conditions of single and concurrent access.
• Behavioral observations were conducted to assess amphetamine stereotypy.

Main Results:

• Concurrent access to both reinforcers generally increased responding for each compared to single-reinforcer conditions.
• Amphetamine-induced stereotyped behaviors were observed but did not impede rapid lever pressing for brain stimulation.
• Rats demonstrated the ability to modulate their responding based on the availability of different reinforcers.

Conclusions:

• Rats can effectively manage concurrent operant responding for both drug and brain stimulation reinforcers.
• Brain stimulation remains a potent reinforcer even in the presence of amphetamine, suggesting distinct neural pathways or motivational systems.
• These findings contribute to understanding the complex interplay of reward systems in the brain and have implications for addiction models.