First Advisor

Lafosse, Jose M.


Regis College

Degree Name



Regis College Senior Honors Program

Document Type

Thesis - Open Access

Number of Pages

45 pages


Enriched environments (EE) integrate complex housing conditions with social stimulation and are shown to ameliorate symptoms of depression in rats with as much success as pharmacological treatment. Furthermore, rearing in EE is associated with an increase in hippocampal neourgenesis. This study attempted to demonstrate the depression related behavioral effects of rearing in EE in comparison to rearing in social isolation (SI) using a sucrose preference test (SPT) and forced swim test (FST). I hypothesized that rats reared in EE would exhibit less anhedonia and behavioral despair during and after exposure to a chronic mild stress (CMS) procedure and would show an increased density of neurons in the hippocampus. The rats were reared for 61 days in either EE or SI conditions and then exposed to CMS for 14 days. Behavioral measures were taken during and after CMS. Upon completion of the behavioral study, three rats form each condition were sacrificed and neuronal density in the hippocampus was determined. I found that EE prevented behavioral despair demonstrated by the FST and that EE increased the density of neurons in the hippocampus providing a possible mechanism for the behavioral effects of EE.

Date of Award

Spring 2009

Location (Creation)

Denver, Colorado

Rights Statement

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