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Date of Award

5-6-2021

Document Type

Restricted Thesis: Campus only access

Degree Name

Bachelor of Arts

Department

Psychology

First Advisor

Dr. Kelly Lambert

Abstract

For the past century, a wide range of disciplines have relied on the laboratory rat, R. norvegicus, to make key advances in biomedical research. While this model has helped to shed light on the genetic and neural underpinnings of many conditions and illnesses, there is still debate about its translational value to human psychiatric disorders. The purpose of the present study was to conduct a thorough analysis of morphological and neurobiological differences between wild caught and laboratory reared R. norvegicus in order to evaluate the impacts of standard housing conditions on biomedical research outcomes. In comparisons of weight-matched laboratory and wild-caught male and female rats, wild rats exhibited higher brain/body ratios, heavier cerebellar brain areas, and larger adrenals and spleens. Hormone assays with corticosterone (CORT) and dehydroepiandrosterone (DHEA) indicated that wild rats have significantly more reactive stress response systems. Further, total cell and neuron counts were estimated using isotopic fractionation (IF) and showed that wild-rats have significantly more cells and a higher percentage of neurons in the cerebellum compared to laboratory rats. Overall, the findings of the current study add to a basic and fundamental growing understanding of the differences between wild and laboratory rats. As the current model of laboratory rat research is being re-evaluated by scientists, it is increasingly relevant to understand more about the natural ecology of this species and how differential environmental conditions have influenced its evolution throughout history.

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