Visual Spatial Learning and Memory in Fragile X Syndrome and fmr1 Knockout Mice

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Title: Visual Spatial Learning and Memory in Fragile X Syndrome and fmr1 Knockout Mice
Authors: MacLeod, Lindsey
Date: 2013
Abstract: This dissertation describes separate but related studies that explore visual spatial learning and memory in Fragile X Syndrome. Across all studies, either the performance of individuals affected by FXS and/or fmr1 KO mice was compared to comparison controls on seven H-W mazes of increasing difficulty levels. Study one employed the traditional configuration of the H-W mazes to evaluate performance variables that include latency to complete the maze and number of the errors. The results of study 1 revealed significant differences in performance for both FXS groups as compared to mental age-matched comparison individuals and wild type mice, respectively. In contrast to the FXS group, performance of the comparison group improved as indicated by significantly fewer errors across trials. A similar pattern of results was observed when latency across trials was analyzed. Taken together, the results of study one support the hypothesis that a selective deficit in spatial learning and memory characteristic of the FXS phenotype can be observed in the murine model of FXS, if equivalent tasks are employed in testing humans and mice. Study two expanded on these findings by adding landmarks to the maze environment to evaluate how these may impact spatial learning and memory in fmr1 KO mice. Contrary to our hypotheses, landmarks significantly impaired wild type control performance. In addition, results revealed that the performance of the fmr1 KO mice generally did not differ between landmark and non-landmark tasks, indicating that the presence of landmarks neither enhanced nor hindered mouse performance. Lastly, study three entailed a more in-depth behavior analysis of maze navigation performance for FXS individuals from study 1. Consistent with the hypotheses and findings from study 1, results revealed significant differences in performance variables between individuals, with FXS participants generally performing worse than the comparison group participants. Taken together, the results of study 3 generally supported the hypothesis that there was greater impairment in performance for individuals affected by FXS as compared to controls. This impairment was evident in the pattern of pathways taken to solve H-W mazes, consistent with the notion that affected individuals employed different behavioral strategies.
URL: http://hdl.handle.net/10393/26001
http://dx.doi.org/10.20381/ruor-6693
CollectionThèses, 2011 - // Theses, 2011 -
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