Date of Award

2022

Document Type

Honors Thesis (Open Access)

Department

Colby College. Psychology Dept.

Advisor(s)

Derek Huffman

Second Advisor

Melissa Glenn

Abstract

Preclinical rodent models of depression are important for improving our understanding of the behavioral and neurobiological implications of the disorder. However, the current behavioral assays used to assess depressive symptoms in rodents have substantial shortcomings; they are basic, test animals individually, and do not evaluate animals for extended periods. The primary goals of the present study, which was divided into two experiments, were to develop a novel task that could be used to study spatial memory and to apply the task to rodent models of depression. Both experiments used a circular arena with 10 identical jars to analyze the spatial navigation abilities of rats. To target the intersection between social and cognitive changes that result from depression, the location of a food reward in the arena was signaled to the rats by a social cue. Unlike a traditional conditional discrimination task, the identity of a conspecific rat served as the context which indicated where an animal should navigate, and rats performed the task in pairs. In Experiment 1, we demonstrated that rats were able to use a social context to determine the location of the food reward. Moreover, rats performed better in the task when they were paired with their cagemate compared to when they were paired with a different rat. In Experiment 2, the task was applied to corticosterone models of depression. We found that performance on the task may have been impaired by exposure to high levels of corticosterone. Thus, the present thesis contributes to our understanding of the corticosterone model of depression and extends upon the current behavioral assessments used to study depression in rodents.

Keywords

Major Depressive Disorder, Behavioral Neuroscience, Spatial Memory, Navigation, Social Wayfinding

Download

Share

COinS