The medial prefrontal cortex during flexible decisions: Evidence for its role in distinct working memory processes

Area of Science:

• Neuroscience
• Cognitive Science
• Behavioral Neuroscience

Background:

• Working memory involves encoding, maintenance, and retrieval of information.
• The specific roles of brain structures in these components are not fully understood.
• The medial prefrontal cortex (mPFC) is implicated in executive functions and decision-making.

Purpose of the Study:

• To causally investigate the role of the rat medial prefrontal cortex (mPFC) in distinct working memory processes.
• To disambiguate the mPFC's contribution to encoding, maintenance, and retrieval during a serial spatial reversal learning (SSRL) task.

Main Methods:

• Transient optogenetic disruptions of the mPFC in rats during an SSRL task.
• Analysis of multiple performance metrics to assess working memory function.
• Examination of task epoch-specific performance and vicarious-trial-and-error rates.

Main Results:

• mPFC disruption impaired performance during the choice epoch of initial learning.
• Disruptions affected performance across all epochs (delay, choice, return) during flexible decision-making.
• mPFC disruption reduced vicarious-trial-and-error rate modulation in response to changing task demands.

Conclusions:

• The mPFC plays a critical role in working memory retrieval.
• The mPFC is involved in encoding and maintenance when conflicting memories challenge task demands.
• The mPFC facilitates flexible updating of behavior based on environmental changes, utilizing working memory.