Voluntary exercise improves performance of a discrimination task through effects on the striatal dopamine system

Area of Science:

• Neuroscience
• Behavioral Neuroscience
• Exercise Science

Background:

• Voluntary exercise enhances discrimination learning in a modified T-maze.
• The dorsolateral striatum (DLS) is implicated as a key brain region for this learning task.

Purpose of the Study:

• To investigate the role of dopamine receptors in the DLS in exercise-associated learning facilitation.
• To determine if exercise alters dopamine D1 and D2 receptor function within the DLS.

Main Methods:

• Rats underwent voluntary exercise or were sedentary.
• Dopamine receptor antagonists (D1R and D2R) were infused into the DLS.
• Performance in a T-maze discrimination task was assessed.

Main Results:

• Dopamine D1 receptor antagonist infusion facilitated learning in nonexercising rats but not exercising rats.
• Dopamine D2 receptor antagonist infusion impaired learning in exercising rats but not nonexercising rats.

Conclusions:

• Exercise-induced facilitation of T-maze discrimination learning may involve decreased dopamine D1 receptor activation and increased dopamine D2 receptor activation in the DLS.
• These findings suggest a neurochemical mechanism for how exercise impacts cognitive flexibility.