Amphetamine reduces reward encoding and stabilizes neural dynamics in rat anterior cingulate cortex.

Area of Science:

• Neuroscience
• Behavioral Pharmacology
• Computational Neuroscience

Background:

• Psychostimulants like d-amphetamine (AMPH) produce paradoxical behavioral effects, increasing task engagement and effort while decreasing reward valuation.
• The anterior cingulate cortex (ACC) is crucial for signaling the cost-benefit utility of actions.

Purpose of the Study:

• To investigate the neural correlates of AMPH's paradoxical effects in the ACC.
• To understand how AMPH influences neural activity patterns related to reward and effort.

Main Methods:

• Simultaneous neural recordings from ensembles of neurons in freely-moving rats.
• Analysis of neural activity trajectories encoding task events under varying AMPH doses.

Main Results:

• AMPH decreased reward signaling but not effort signaling in the ACC.
• Low-dose AMPH contracted neural trajectories and reduced variance, suggesting increased network stability.
• High-dose AMPH expanded neural trajectories and variance, indicating impaired network stability and task execution.

Conclusions:

• AMPH's effects on ACC network stability and excitability explain its paradoxical behavioral impact.
• Low doses may enhance task execution through accelerated neural scripting, while high doses impair it via excessive noise and deviation.
• Findings offer insights into psychostimulant mechanisms and cost-benefit processing in the brain.