Prefrontal cortical mechanisms underlying delayed alternation in mice

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Behavioral Neuroscience

Background:

• The prefrontal cortex (PFC) is vital for maintaining task-relevant information in goal-directed behaviors.
• The specific role of the medial prefrontal cortex (mPFC) in complex cognitive tasks requires further elucidation.

Purpose of the Study:

• To investigate the functional role of the medial prefrontal cortex (mPFC) in a delayed alternation task.
• To examine the contribution of mPFC to both the acquisition and performance of cognitive tasks.
• To explore the mechanisms of GABAergic inhibition within the mPFC during task execution.

Main Methods:

• Utilized excitotoxic lesions, local inactivation (muscimol infusions), and optogenetics in mice.
• Employed a novel operant delayed alternation task with manipulated delay durations.
• Optogenetically activated parvalbumin (PV)-expressing GABAergic interneurons in the mPFC of PV-Cre mice.

Main Results:

• mPFC lesions impaired acquisition of delayed alternation, unlike dorsal hippocampus or ventral striatum lesions.
• Muscimol infusions into the mPFC disrupted performance in well-trained animals.
• In vivo optogenetic activation of mPFC PV-interneurons significantly impaired task performance.

Conclusions:

• The medial prefrontal cortex (mPFC) plays a critical role in the acquisition and performance of delayed alternation tasks.
• GABAergic inhibition mediated by PV-interneurons in the mPFC is essential for successful task execution.
• Findings highlight the mPFC's importance in cognitive control and goal-directed behavior.