Neural correlates of sensation and navigation in the retrosplenial cortex

Abstract

By virtue of its anatomical connections, the retrosplenial cortex (RSC) is well suited to mediate bidirectional communication between the hippocampal formation and the neocortex. However, what information is encoded in the firing of RSC neurons is largely unclear. I used 2-photon calcium imaging to measure RSC population activity during a goal-directed virtual spatial task that was sometimes complemented by drifting gratings visual stimuli. Over 10% of RSC neurons, mainly in superficial layers, showed place fields with properties similar to CA1 place cells measured in the same task. A distinct subset of neurons (~15%), predominantly in agranular RSC, showed pronounced responses to the visual stimuli. Some of these RSC visual neurons were specifically selective for the speed and direction of visual motion. The results suggest that RSC contains multiple functional cell types distributed differentially across depths and subregions showing responses to external sensory stimulation and internal navigational signals.