Theses and Dissertations at Montana State University (MSU)
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Item Antisense oligonucleotide inhibition of calcium/calmodulin-dependent protein kinase II and working memory deficits in the gerbil(Montana State University - Bozeman, College of Letters & Science, 2002) Hoopes, Barry JustinItem Object and spatial recognition in the ischemic gerbil(Montana State University - Bozeman, College of Letters & Science, 2010) Clement, Bridget Williams; Chairperson, Graduate Committee: A. Michael BabcockThe Mongolian gerbil is extensively used to model transient cerebral ischemia, a type of stroke that can occur with anoxia and cardiac arrest. A global ischemic insult in the gerbil produces damage to hippocampal CA1 pyramidal cells comparable to that observed in humans. A limited number of models are available to evaluate the behavioral consequences of cerebral ischemia in the gerbil. The goal of the present experiments was to evaluate the impact of transient cerebral ischemia on object and spatial recognition memory as these tasks have not been previously utilized with the gerbil model. Following ischemic insult (5-min bilateral carotid occlusion) or sham procedure, gerbils were tested in a familiar environment with novel objects. A familiarization phase followed by separate test phases for presentations of a novel object or object location were conducted. Exploratory behavior for the novel object or object location was evaluated using an automated tracking system. Results indicated that both ischemic and sham subjects were able to recognize the novel object when placed in the environment. However, when confronted with a familiar object, placed in a novel location, neither group exhibited a significant increase in exploratory behavior. A second experiment was conducted to further investigate the spatial recognition task. Subjects were habituated to the apparatus in addition to the experimental objects. Under this experimental condition, both groups exhibited significant exploratory behavior for the object placed in the novel location. The ischemic and control groups differed from each other during habituation with ischemic subject showing significantly higher activity levels. It is possible that differences between the groups remain but that these recognition findings are a result of extended habituation to the experimental objects. Further investigation of this matter is needed to determine the effect of prior object exposure on exploratory behavior in the spatial recognition task.Item Neuroprotective potential of methamphetamine : behavioral and histological analysi(Montana State University - Bozeman, College of Letters & Science, 2007) Weeden, Christy Samantha Star; Chairperson, Graduate Committee: Michael BabcockStroke is a leading cause of death and ischemic stroke is the most common form. The deficits that follow ischemic stroke include memory and learning impairment. There are presently no treatments that can combat the effects of ischemia after the attack has occurred. Immediately following insult, locomotor activity increases in rodent models. The goal of the current research is to determine if methamphetamine administration following ischemic attack will have neuroprotective effects and prevent changes in locomotor behavior that are observed following insult. Ischemic insult was induced in gerbils by clamping the carotid arteries for 5 mins. Subjects in the sham surgical condition underwent similar surgical procedures, but the carotids were not clamped. Then, subjects were assigned randomly to saline or methamphetamine (5 mg/kg) injection groups. Drug treatment was administered within 2 mins of surgery. Measures of distance traveled, average speed, and number of line crossings were evaluated.Item Hippocampal damage and novelty preference in the ischemic gerbil : dissociating object and arrangement memory(Montana State University - Bozeman, College of Letters & Science, 2007) McNeill, Damon Lee; Chairperson, Graduate Committee: A. Michael BabcockThe most insidious consequences of transient ischemia are its effect on the hippocampus and the memory systems it serves. The novelty preference test is a direct measure of memory function and has been used in the rat and primate animal models. The gerbil animal model has been used extensively to study the mechanism of ischemic brain damage; however, the novelty preference paradigm has not been used to study memory impairment in this species. In addition, the novelty preference paradigm has not been tested with models of ischemia. In the present experiment, Mongolian gerbils were tested in two different types of novelty-preference tasks (Object and Arrangement) following either ischemic insult or a sham control surgery.Item Behavioral consequences following AAV mediated hippocampal EAAC1 knockdown(Montana State University - Bozeman, College of Letters & Science, 2007) Coombs, Katie Marie; Chairperson, Graduate Committee: Michael BabcockThe neuronal glutamate transporter EAAC1 (EAAT3) is present in hippocampal neurons to prevent excessive glutamate accumulation. Glutamate receptor-dependent synaptic plasticity is important for learning and memory. The present study investigates behavior associated with blocking the glutamate transporter EAAC1. To manipulate EAAC1 function, rats were intrahippocampally injected with a adeno-associated viral (AAV) vector encoding an EAAC1 antisense mRNA sequence or an AAV empty cassette. Twenty-eight days following surgery, rats were tested in a delayed matching-to-place (DMTP) watermaze task to examine spatial memory, which is hippocampaldependent. Rats treated with EAAC1 antisense exhibited shorter latencies to locate the target platform relative to controls (p < 0.05). These data indicate that microinfusion of AAV encoding EAAC1 antisense significantly altered performance on task involving glutamate transmission and the hippocampus.