Spatial Encoding in the Orbitofrontal Cortex During the Adapted Two-Step Task for Rats

Abstract

Humans and animals make decisions every day that call upon internal models of learned action-outcome associations. The use of these models in decision-making is known as model-based planning, which is a process whose neural underpinnings continue to be outlined. It has been shown previously that the orbitofrontal cortex (OFC) is a key player in model-based planning due to the brain region’s established role in value-based cognition and the relevance of value-encoding for goal-oriented decisions. Previous research suggests the OFC might possess spatial-encoding properties that contribute to cognitive maps encoding features of a task space beyond economic value. To investigate this, I analyzed electrophysiology data obtained from the OFC in a previous study in order to investigate the spatial encoding properties of the region during the completion of a task – the two-step task – that requires model-based planning. It appears that subsets of OFC cells, in fact, do encode a rat’s spatial location during completion of the two-step task, and that certain cells’ activity profiles are modulated by different spatial locations. The response profiles of these cells indicate spatial-encoding properties similar to those of hippocampal cells. Connectivity between the two brain regions could therefore impart spatial encoding properties to the OFC to contextualize economic value and encode spatial pathways leading to reward. This is a preliminary study, and more statistical analysis is necessary to verify these findings and further delineate how these two brain regions function during model-based planning.