Ventral striatal dopamine modulation of different forms of behavioral flexibility

Area of Science:

• Neuroscience
• Behavioral Neuroscience
• Neuropharmacology

Background:

• Behavioral flexibility relies on prefrontal cortex and striatal interactions.
• The specific role of ventral striatal dopamine (DA) in distinct flexibility forms remains unclear.

Purpose of the Study:

• To investigate the involvement of dopamine receptors in the nucleus accumbens (NAc) core during between- and within-strategy shifts.
• To elucidate the differential roles of D1 and D2 receptors in complex and simple behavioral flexibility.

Main Methods:

• Rats were trained on operant chamber tasks for strategy set-shifting and reversal learning.
• Microinfusions of D1 (SCH23390) and D2 (eticlopride) receptor antagonists were administered into the NAc core.
• Supranormal activation of D1 (SKF81297) and D2 (quinpirole) receptors was also assessed.

Main Results:

• D1 receptor antagonism impaired set-shifting, hindering new strategy maintenance.
• Excessive D2 receptor activation impaired set-shifting and reversal learning, causing perseverative deficits.
• D1 receptors selectively facilitate complex strategy shifts, while D2 receptor overactivity broadly impairs flexibility.

Conclusions:

• Mesoaccumbens DA acting on D1 receptors is crucial for complex behavioral flexibility involving strategy shifts.
• Abnormal D2 receptor activity leads to more generalized deficits in behavioral flexibility.
• Dysfunction in the DA system may contribute to executive functioning deficits in related disorders via altered mesoaccumbens DA activity.