USING A NOVEL APPARATUS TO STUDY EXTERNAL CUE-BASED NAVIGATION IN YOUNG AND AGED RODENTS

Abstract

In order to study age-related differences in rodent navigation and the neural basis of cue-based spatial processing, a novel behavioral apparatus was used, termed the Instantaneous Cue Rotation (ICR) arena. After sufficiently training rodents aged 9 months (young group) and 22 months (old group), the animals navigation performance was assessed on the accompanying ICR task. We expected there to be age-related differences in task performance and anticipated older animals would be slower to realign their goal-navigation behavior following cue rotation. Our experimental results validated the use of the ICR arena as a means to use external cue rotation to exercise control over rats’ running behavior. Additionally, when comparing young and aged rats, we observe that external cues have less influence over the running behavior of aged rats as compared to young rats, which is consistent with our understanding of age-related deficits in external cue processing. In the future we hope to surgically implant rats with an electrophysiological hyperdrive that contains independently moveable tetrode recording probes in order to measure neural activity in both the CA1 region of the hippocampus and the medial entorhinal cortex. Both areas are associated with spatial navigation and are known to be susceptible to age-related changes. We hope completion of this experiment will allow us to gain further insight and knowledge on the cellular mechanisms responsible for creating and updating the overall cognitive map in rodent hippocampi and surrounding neural structures, and how this is altered in aging.