Rhythmic activity in the medial and orbital frontal cortices tracks reward value and the vigor of consummatory behavior

ABSTRACT

This study examined how the medial frontal (MFC) and orbital frontal (OFC) cortices process reward information to guide behavior. We simultaneously recorded local field potentials in the two areas as rats consumed liquid sucrose rewards and examined how the areas collectively process reward information. Both areas exhibited a 4-8 Hz “theta” rhythm that was phase locked to the lick cycle. The rhythm similarly tracked shifts in sucrose concentrations and fluid volumes, suggesting that it is sensitive to general differences in reward magnitude. Differences between the MFC and OFC were noted, specifically that the rhythm varied with response vigor and absolute reward value in the MFC, but not the OFC. Our findings suggest that the MFC and OFC concurrently process reward information but have distinct roles in the control of consummatory behavior.