Dopamine depletion impairs frontostriatal functional connectivity during a set-shifting task.

Area of Science:

• Neuroscience
• Cognitive Psychology
• Neuroimaging

Background:

• Dopamine plays a critical role in cognitive functions, including executive control.
• Understanding dopamine's influence on brain network connectivity is essential for explaining cognitive performance.

Purpose of the Study:

• To investigate the impact of transient dopamine depletion on functional brain connectivity.
• To examine how dopamine modulates prefrontostriatal connectivity during the Wisconsin Card Sorting Task (WCST).

Main Methods:

• Functional magnetic resonance imaging (fMRI) was used to analyze brain activity.
• A psychophysiological interaction (PPI) analysis identified functional connectivity during the WCST.
• Participants underwent scanning after consuming either a dopamine-depleting or a balanced amino acid mixture.

Main Results:

• Dopamine depletion abolished significant prefrontostriatal connectivity observed during set shifting in the balanced condition.
• Reduced prefrontostriatal connectivity correlated with slower response times after set shifts.
• Dopamine depletion decreased deactivation in brain regions typically suppressed during attention-demanding tasks.

Conclusions:

• Functional connectivity between the frontal lobes and basal ganglia is vital for efficient set shifting during the WCST.
• Dopamine significantly modulates this corticostriatal connectivity, impacting cognitive performance.
• Dopamine depletion affects both task-related connectivity and the suppression of irrelevant brain activity.