Hippocampal contributions to value-based decision-making

People with damage to orbitofrontal cortex (OFC) have specific problems making decisions, whereas their other cognitive functions are spared. Neurophysiological studies have shown that OFC neurons fire in proportion to the value of anticipated outcomes. Thus, a central role of OFC is to guide optimal decision-making by signaling values associated with different choices. Until recently, this view of OFC function dominated the field. New data, however, suggest that OFC may have a much broader role in cognition by representing cognitive maps that can be used to guide behavior. This function has traditionally been ascribed to the hippocampus raising questions as to the nature of their individual contributions to behavior and their interactions. In this talk, I will present a series of recent experiments from my lab that seek to understand OFC-hippocampal interactions and their contribution to value-based decision-making. I will present a model of this process in which hippocampus represents a state-transition graph, and OFC uses knowledge of the reward’s location to calculate the value of the vertices in the graph, thereby helping to guide the optimal choice at each decision point.  This infusion of new theoretical ideas from formal models of the cognitive map can help to align our understanding of OFC value representations to naturalistic behavior and ultimately help to explain why OFC damage is so catastrophic for everyday decision-making.