Dopamine D2 receptors modulate the cholinergic pause and inhibitory learning.

Area of Science:

• Neuroscience
• Behavioral Neuroscience
• Neuropharmacology

Background:

• Cholinergic interneurons (CINs) in the striatum exhibit pauses in activity upon salient stimuli.
• Dopamine D2 receptors (D2Rs) are implicated in regulating these pauses, but their in vivo behavioral relevance remains unclear.
• The role of CIN pauses in behavior and dopamine modulation requires further investigation.

Purpose of the Study:

• To investigate the behavioral significance of dopamine D2 receptor (D2R)-mediated regulation of cholinergic interneuron (CIN) pauses in the nucleus accumbens (NAc).
• To determine the impact of altered D2R function in CINs on acetylcholine (ACh) release and inhibitory learning in vivo.
• To elucidate the role of CIN activity modulation by dopamine in cognitive functions.

Main Methods:

• Slice electrophysiology to assess CIN activity and D2R function.
• In vivo measurements of acetylcholine (ACh) levels during behavioral tasks.
• Behavioral analysis using a Go/No-Go task to evaluate inhibitory learning.

Main Results:

• Upregulation of D2Rs in NAc CINs prolonged the pause in neuronal activity ex vivo.
• Enhanced D2R function enlarged stimulus-evoked decreases in ACh levels during behavior.
• Increased ACh dips correlated with deficits in learning to inhibit responses in the Go/No-Go task.

Conclusions:

• CIN D2Rs are crucial for modulating responses to salient stimuli.
• The CIN pause, regulated by D2Rs, plays a significant role in inhibitory learning.
• Findings have implications for understanding and treating disorders like schizophrenia and ADHD, which involve altered striatal dopamine and ACh signaling.