Date of Award

12-2007

Degree Name

Master of Arts

Department

Psychology

First Advisor

Dr. Lisa E. Baker

Second Advisor

Dr. Alan D. Poling

Third Advisor

Dr. Bradley E. Huitema

Access Setting

Masters Thesis-Open Access

Abstract

Recent attention has focused on the possibility that even low-level Pb exposure can produce subtle neurological impairments in the absence of overt signs of toxicity. Previous behavioral assessments of learning and memory using DMTS procedures have documented learning impairments in monkeys exposed to Pb during early postnatal development, and although a variety of operant behavioral assays have documented detrimental effects of dietary Pb treatment in rats, the DMTS procedure has not been examined in rats following short-term low levels of Pb through dietary exposure. Thus, the objective of this study was to measure the degree of cognitive impairment produced by chronic dietary Pb exposure in rats and to determine the degree to which the separate aspects of this test are sensitive to that impairment. Animals exposed to Pb acetate for a 90 day period were trained on a DMTP task. Following acquisition, animals were introduced to a non-matching reversal of the DMTP design (DNMTP). Delay-dependent significant differences in response accuracy and number of sessions until criterion was met were found between treatment groups on the reversal task only. These results indicate that a sub-chronic duration of dietary Pb exposure does produce significant cognitive impairment in rats which are measureable not through the initial acquisition of the DMTP task, but in the subsequent acquisition of the reversal of that task.

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