Visual cue representation without movement or task demands in the rodent hippocampus.

Rodent hippocampus is believed to be critically involved in generating selectivity to allocentric space, called place cells, which are abstract and prospective. Such responses are thought to require both distal visual cues and self-motion cues. In primates, however, hippocampal neurons encode object-place association without any locomotion requirements. We explored the contributions of distal visual cues and proximal olfactory and self-motion cues on hippocampal firing. Our unique VR design allowed us to dissociate the contributions of distal visual cues and head movements on hippocampal firing. We found that a third of the neurons showed selective responses with respect to head movements. This head movement selectivity was found in experiments where the animal performed navigational tasks in the VR. These results suggest that multisensory association present in the real world plays a stronger role in hippocampal firing than navigational demands tied to virtual navigation. Our work furthers the understanding of multi-sensory contributions to hippocampal firing