Differential functions of the dorsal and intermediate regions of the hippocampus for optimal goal-directed navigation in VR space

Abstract

Goal-directed navigation requires the hippocampus to process spatial information in a value-dependent manner, but its underlying mechanism needs to be better understood. Here, we investigated whether the dorsal (dHP) and intermediate (iHP) regions of the hippocampus differentially function in processing place and its associated value information. Rats were trained in a place-preference task involving reward zones with different values in a visually rich VR environment where two-dimensional navigation was possible. Rats learned to use distal visual scenes effectively to navigate to the reward zone associated with a higher reward. Inactivation of the dHP or iHP with muscimol altered navigational patterns differentially. Specifically, measurements of the efficiency and accuracy of wayfinding behavior using directional analysis showed that iHP inactivation induced more severe damage to value-dependent navigation than dHP inactivation. Our findings suggest that the dHP is more critical for accurate spatial navigation to the target location per se, whereas the iHP is critical for finding higher-value goal locations.