Medial-lateral organization of the orbitofrontal cortex.

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Decision Making

Background:

• The orbitofrontal cortex (OFC) is implicated in value-based decision-making.
• Human neuroimaging suggests distinct medial and lateral OFC subregions process positive and negative stimulus valences, respectively.
• Neurophysiological evidence has not consistently supported this valence-based segregation model.

Purpose of the Study:

• To reconcile conflicting accounts of OFC function by investigating neural activity across the OFC's medial-lateral extent.
• To determine if specific OFC subregions exhibit valence selectivity (processing positive vs. negative stimuli).
• To identify the organizing principles of value representation within the OFC.

Main Methods:

• Recorded neural activity from the entire orbital surface of monkeys performing a task involving rewards and punishments.
• Utilized secondary reinforcement (gain or loss) to manipulate value.
• Analyzed neural responses in relation to stimulus value and task structure.

Main Results:

• No convincing evidence for valence selectivity was found in any OFC region.
• Significant differences were observed between neurons in the central OFC and the inferior-lateral orbital convexity.
• Central OFC neurons encoded value information derived from the task's structure, while inferior-lateral neurons encoded external stimulus value.

Conclusions:

• The findings challenge the prominent theory of valence segregation within the OFC.
• A fundamental organizing principle for value processing in the OFC may involve distinctions in encoding external stimulus value versus internally derived task-structure value.
• These results provide a new framework for understanding OFC function in value-based cognition.