Date of Award

Spring 4-24-2015

Degree Type

Thesis

Degree Name

MS Experimental Psychology

Department

Psychology

Advisor

Michael Vigorito, Ph.D

Committee Member

Amy Hunter, Ph.D

Committee Member

Jeffrey Levy, Ph.D

Committee Member

Kelly Goedert, Ph.D

Keywords

estradiol, spatial navigation, learning, memory, aging, male rats

Abstract

Treatment with 17β- estradiol has been shown to ameliorate age related deficits in spatial learning and memory as well as to promote the use of an allocentric strategy during spatial navigation. While the majority of research using 17β- estradiol has been done using females rodents, there have been studies showing an improvement in spatial learning and memory and promoted use of allocentric strategies in spatial navigation in males as well. In males testosterone (T) is metabolized into estradiol by aromatase. As circulating levels of T decline with aging there is less available T to be metabolized into estradiol. The current study sought to determine whether treatment of aged male rats with17β- estradiol improves spatial learning and memory in a hole-board task and promotes the use of an allocentric strategy (use of extramaze cues). Control and 17β- estradiol treated groups showed decreased latencies to find all baited holes and a significant decrease in visits and revisits to unbaited holes over days. Inconsistent with prior research there was no group difference in performance, and probe tests with extramaze cues removed indicated that an allocentric strategy was not used by either group. It is possible that the lack of group differences was due to estradiol levels that were too low or too high. These results also suggest that rats tested in a hole-board task may prefer other search strategies over an allocentric strategy. Any study using the hole-board task to investigate allocentric search performance must include probe tests to confirm that the rats are actually using the provided extramaze cues to guide their search behavior.

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