Homing with locale, taxon, and dead reckoning strategies by foraging rats: sensory hierarchy in spatial navigation

Abstract

Studies on foraging rats suggest that they can use visual, olfactory, and self-movement cues for spatial guidance, but their relative reliance on these different cues is not well understood. In the present study, rats left a hidden refuge to search for a large food pellet located somewhere on a circular table, and the accuracy with which they returned to the refuge with the food pellet was measured. Cue use was manipulated by administering probe trials from novel locations, blindfolding, moving the home cage relative to the table, rotating the table and using combinations of these manipulations. When visual cues were available and a consistent starting location used, a visual strategy dominated performance. When blindfolded, the rats used olfactory cues from the surface of the table and from the starting hole. When olfactory stimuli were made uninformative, by changing the starting hole and rotating the table, the rats still homed accurately, suggesting they used self-movement cues. In a number of cue combinations, in which cues gave conflicting information, performance degraded. The results suggest that rats display a hierarchical preference in using visual, olfactory and self-movement cues while at the same time being able to reaffirm or switch between various cue combinations. The results are discussed in relation to ideas concerning the neural basis of spatial navigation.