A Functional Gradient in the Rodent Prefrontal Cortex Supports Behavioral Inhibition

Area of Science:

• Neuroscience
• Behavioral Neuroscience
• Cognitive Neuroscience

Background:

• Action timing relies on a balance between movement initiation and inhibition.
• Impulse control disorders involve the prefrontal cortex (PFC), highlighting its role in timing actions.
• The functional heterogeneity of the PFC is crucial for understanding its role in action control.

Purpose of the Study:

• To systematically analyze the functional roles of medial PFC (mPFC) and orbitofrontal cortex (OFC) subareas in action control.
• To investigate the specific contributions of prelimbic cortex (PL), infralimbic cortex (IL), and ventral OFC (VO) to action timing.
• To elucidate the opposing roles of mPFC subregions and the OFC in proactive versus reactive movement control.

Main Methods:

• Optogenetic and electrophysiological techniques were used in rodent models.
• Inactivation of specific mPFC and OFC subareas.
• Electrophysiological recordings of neuronal activity during response preparation and execution.

Main Results:

• Inactivation of mPFC subareas altered response timing, increasing premature responses in the prelimbic cortex (PL) and decreasing them in the infralimbic cortex (IL).
• A decrease in neuronal activity in a PL subpopulation preceded premature responses.
• Inhibition of the ventral OFC (VO) impaired rapid responses to external cues, and mPFC activity better predicted trial outcomes than OFC activity.

Conclusions:

• The infralimbic cortex (IL) and prelimbic cortex (PL) have opposing roles in proactive behavior.
• The orbitofrontal cortex (OFC) is primarily involved in reactive movement control.
• This research clarifies the functional heterogeneity of the PFC, offering insights into PFC-associated impulse control disorders.