Temporal Dynamics of Investigation in Rodents

Abstract

We recently characterized the Social versus Food Preference Test, a behavioral paradigm designed for investigating competition between the choice to seek social interaction versus food, and examined how stimulus preference was modulated by social isolation and/or food deprivation using a 2×2 within-subjects design in C57BL/6 mice and Wistar rats.

During 10-min tests, each subject was placed in a 3-chamber apparatus where it could freely explore a social stimulus (novel species-, age- and sex-matched conspecific) and a food stimulus (standard lab chow) that were corralled on opposite ends. Previously, we found that social isolation did not alter stimulus preference in either species, but that food deprivation induced a food preference in mice and reduced a social preference in rats. Here, we expanded our analyses by determining how time spent in stimulus zones changed over the course of the test periods. In mice, time in the social zone was stable across the test period under all conditions, while time in the food zone increased over the course of the tests conducted under food-deprived conditions. In rats, time in the social and food zones was stable across the test period under all conditions. These results indicate that the length of the test matters for choice behavior in mice but not in rats because we showed that the food deprivation-induced food preference in mice is driven by behavior in the latter portion of the test, while the food deprivation-induced reduction in social preference in rats is reflective of behavior throughout the test.