Re-evaluating the role of the orbitofrontal cortex in reward and reinforcement

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Decision Science

Background:

• The orbitofrontal cortex (OFC) and ventromedial prefrontal cortex (vmPFC) are crucial for reward processing and behavioral flexibility.
• Existing theories often propose distinct roles for lateral OFC (lOFC) in punishment/error and ventromedial/medial OFC (vmPFC/mOFC) in reward processing.
• Recent research challenges these specialized views, suggesting a more nuanced functional differentiation.

Purpose of the Study:

• To review and synthesize recent experimental findings on the functional differences between the lOFC and vmPFC/mOFC.
• To re-evaluate the roles of these regions in reward, error, and decision-making processes.
• To investigate the impact of lesions in these areas on behavioral flexibility and choice maintenance.

Main Methods:

• Review of recent human and macaque experiments.
• Analysis of lesion studies.
• Examination of functional magnetic resonance imaging (fMRI) data.

Main Results:

• lOFC is involved in assigning credit for both reward and error outcomes to specific stimuli and linking stimuli to reward types.
• vmPFC/mOFC is critical for evaluation, value-guided decision-making, and maintaining choices across successive decisions.
• Contrary to popular belief, lesions in neither lOFC nor vmPFC/mOFC caused perseveration; lOFC lesions increased switching, while mOFC lesions reduced repetition of successful choices.

Conclusions:

• The functional distinction between lOFC and vmPFC/mOFC is not best explained by simple reward vs. error specialization.
• lOFC plays a key role in credit assignment and stimulus-reward linkage.
• vmPFC/mOFC is essential for value-based decision-making and the maintenance of chosen options, facilitating the repetition of successful choices.