Department of Psychology
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This collection contains research from members of the Department of Psychology at George Mason University.
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Browsing Department of Psychology by Subject "Copper"
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Item Spatial memory deficits in a mouse model of late-onset Alzheimer’s disease are caused by zinc supplementation and correlate with amyloid-beta levels(Frontiers Media, 2014-10-22) Flinn, Jane M.; Bozzelli, P. Lorenzo; Adlard, Paul A.; Railey, Angela M.Much of the research in Alzheimer’s disease (AD) that uses mouse models focuses on the early-onset form of the disease, which accounts for less than 5% of cases. In contrast, this study used a late-onset AD model to examine the interaction between increased dietary zinc (Zn) and the apolipoprotein E (ApoE) gene. ApoE ε4 is overrepresented in late-onset AD and enhances Zn binding to amyloid-β (Aβ). This study sought to determine if elevated dietary Zn would impair spatial memory in CRND8 mice (CRND8), as well as mice who carry both the mutated human amyloid precursor protein (APP) and ApoE ε4 genes (CRND8/E4). Mice were provided with either lab tap water or water enhanced with 10 ppm Zn (ZnCO3) for 4 months. At 6 months of age, spatial memory was measured by the Barnes maze. CRND8 mice exhibited significant memory deficits compared to WT mice, as shown by an increased latency to reach the escape box. For the CRND8/E4, but not the CRND8 mice, those given Zn water made significantly more errors than those on lab water. During the probe trial for the WT group, those on Zn water spent significantly less time in the target quadrant than those on lab water. These data suggest that increased dietary Zn can significantly impair spatial memory in CRND8/E4. WT mice given Zn water were also impaired on the 24-h probe trial when compared to lab water WTs. Within the CRND8/E4 group only, levels of soluble Aβ were significantly correlated with average primary latencies. Within the Zn-treated CRND8/E4 group, there was a significant correlation between insoluble Aβ and average primary errors. Levels of the zinc transporter 3, ZnT3, were negatively correlated with soluble Aβ (p < 0.01). These findings are particularly relevant because increased intake of dietary supplements, such as Zn, are common in the elderly—a population already at risk for AD. Given the effects observed in the CRND8/E4 mice, ApoE status should be taken into consideration when evaluating the efficacy of therapies targeting metals.Item The Effect of Zinc and Zinc Plus Copper on Memory(2009-07-16T15:20:33Z) Perez-Casillas, TizocTrace metals exist in low quantities in the human body. Zinc and copper are two trace metals that are essential in the body, yet they must be balanced; otherwise, negative side effects emerge. Zinc has an antagonistic effect on copper, in that an excess amount of zinc absorbed by the body causes a copper deficiency. Furthermore, previous studies have also shown that exposing rats to zinc given both prenatally to the mother and after birth leads to cognitive impairments in adult rats and increased levels of zinc in the rat temporal cortex and hippocampus, which can be rescued in part by adding copper to the diet (Flinn et al., 2005). This experiment examined the effect of giving zinc and zinc plus copper to adult rats in the drinking water. I raised forty-five rats on zinc (15), zinc plus copper (15), and lab water (15). Zinc and zinc plus copper were dissolved in the rats’ drinking water. The group of rats that had no metals added in the water was measured as a baseline (control). Previous experiments have shown that rats raised on zinc could not learn to extinguish a learned fear. The rats in this experiment were subjected to a fear-conditioning task, and I measured the duration of time to extinguish the learned fear. When dosed with zinc, the rats took the longest to extinguish the learned fear when a stimulus was no longer fearful. Since copper partly remediates the zinc effects, the rats dosed with zinc plus copper extinguished faster than the rats dosed solely with zinc and, in some cases, extinguished faster than the rats dosed exclusively on lab water. This experiment further elucidates the effects of zinc on cognitive abilities and the remediation of zinc’s effects when copper is present. From a larger perspective, this study emphasizes that an excess of indispensable minerals and nutrients, which are found in several food products, does not necessarily imply better human functioning.