Differential roles of the medial and lateral orbitofrontal cortex in decision-making

Abstract

Inferring potential outcomes and updating behavior are prerequisites for making flexible decisions. These abilities are highly associated with the functions of the orbitofrontal cortex (OFC). Previous studies proposed that the lateral OFC (lOFC) infers the potential outcomes and the medial OFC (mOFC) encodes the general information to guide behavior. However, recent works suggested that both these two subregions responded to the same decision-related variable. Therefore, the exact roles of mOFC and lOFC in decision-making remain unclear. To study this issue, we conducted an inference-based decision-making experiment combining with functional magnetic resonance imaging techniques. Here we found that both the mOFC and lOFC represented the inferred outcomes, but only the lOFC was responsible for the outcome inference. Although the inferred outcomes were decodable in both subregions, the outcome in the mOFC was context-general coding, whereas it was context-specific in lOFC. Moreover, the functional coupling analysis showed that the mOFC may update behavior through sensory mediation and motor execution, whereas the lOFC may update behavior through task rule retrieving, alertness maintaining, and motor planning. We concluded that the OFC subregions may be collectively activated in decision-making, but their exact roles can be dissociable.