Differential encoding of place value between the dorsal and intermediate hippocampus

Abstract

It is widely held that the hippocampus provides a cognitive map in which event-related information, such as an object, location, and their significance, is organized. However, how an organism's motivational experience is coded in the hippocampus is mostly unknown. Here, we investigated whether dorsal and intermediate regions of the hippocampus are differentially involved in representing changes in the motivational significance of a place. Rats were run in tasks in which various rewards with different degrees of palatability were associated with the same locations while single units were simultaneously recorded along the dorsoventral axis of the hippocampus. Place cells in the intermediate hippocampus remapped immediately after motivational significance decreased and shifted their fields dynamically toward high-value locations. In contrast, place cells in the dorsal hippocampus were mostly unresponsive to the same manipulations. Our findings suggest that the motivational significance of place is uniquely coded in the intermediate hippocampus in goal-directed tasks.