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Dissertations / Theses on the topic 'Spatial learning and memory'
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Robinson, Lianne. "Cannabinoid involvement in spatial learning and memory processes." Thesis, University of Aberdeen, 2004. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU193926.
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Previous studies have revealed that cannabinoids have detrimental effects on learning and memory in humans and animals. Infusion of the exogenous Cannabinoid agonists including D9-tetrahydrocannabinol (D9-THC), HU210 and WIN-55, 212-2 (WIN-2) in animals has consistently been shown to induce deficits in spatial learning and memory. CB1 receptors are evident in the hippocampus and prefrontal cortex; brain areas involved in spatial learning and memory processes. The main aim of this study was to determine the mechanisms underlying these Cannabinoid-induced effects on spatial learning and memory. Lister Hooded rats were used to study the effects of cannabinoids in a sequence of experiments using the water maze. A novel paradigm to test place preference in the water maze was developed and it was revealed that D9-THC induced place aversion whereas WIN-2 had no effect. These aversive properties of D9-THC along with the non-spatial, non-CB1receptor effects of HU210 in reference memory may confound the results obtained for spatial learning and memory. By contrast, WIN-2 deficits would be a genuine result of spatial impairments. WIN-2 induced differential effects on working and reference memory. Reversal with the CB1 antagonist AM281 and vanilloid receptor (VR1) antagonist Iodo-RTX suggest that the WIN-2 effects are mediated via a non-CB 1/non-VR1 receptor located in the hippocampus. The WIN-2 effects could also be mediated via a possible interaction with the cholinergic system, as the cholinesterase inhibitor Rivastigmine was able to reverse the deficit. In addition to exogenous cannabinoids, using the CB1 antagonist SR141716A (SR) observed that endocannabinoids also impaired spatial learning and memory, with SR acting like an inverse agonist. In conclusion both cannabinoids and endocannabinoids impair spatial learning and memory in the water maze, and these deficits may occur via interactions with other neurotransmitter systems. However, whether these actions are mediated via the CB1 or a non-CB1 mechanism still remains unclear.
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Naylor, Susan J. "Spatial context effects on temporal and spatial factors in map memory /." Thesis, Connect to Dissertations & Theses @ Tufts University, 1999.
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Thesis (Ph.D.)--Tufts University, 1999.Adviser: Holly A. Taylor. Submitted to the Dept. of Psychology. Includes bibliographical references (leaves 59-61). Access restricted to members of the Tufts University community. Also available via the World Wide Web;
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Dunn, T. J. "The role of expertise, semantics, and learning in spatial memory." Thesis, Nottingham Trent University, 2012. http://irep.ntu.ac.uk/id/eprint/114/.
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This research investigates the mechanisms that underpin object location memory. It approaches this endeavour by examining a recently reported phenomenon of spatial memory, that of exclusivity. Exclusivity states that given the opportunity to encode or retrieve two spatial memories, only one memory is relied upon for object location. This implies that two memories for where an object is located are not better than one. The role of limited capacity has been implicated in the exclusive processing of multiple objects. Accordingly, the aim of this thesis is to explore possible methods that enhance cognitive capacity in a way to overcome exclusivity. These methods include expertise, semantics and learning. It was proposed that expertise would allow for holistic processing of information and it would therefore increase the likelihood of spatial memory integration. Also, the connection between two related spatial memories was manipulated through the employment of semantic categories to aid in paired memory recognition. In addition to this, a learning paradigm was used which allowed for repeated exposure of spatial information over a 5 and 10 day period. The results of these studies indicate a failure to overcome exclusivity. This suggests that exclusive processing is a robust feature of spatial memory. The findings offer a number of important insights for the field. They provide two important accounts for the processing of multiple object locations. One argues memories are encoded and retreival in a strategic manner to avoid interference. The second proposes fragments of memories are encoded and constructively drawn upon at recall. This thesis also puts forward a unique explanation of how multiple object locations are learnt over time.
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Hirsch, Dale A. "THE ROLE OF LEARNING MODALITY UPON LONG-TERM SPATIAL MEMORY." Cleveland State University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=csu1367532907.
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Niewoehner, Burkhard. "The role of hippocampal synaptic plasticity in spatial memory and learning." Thesis, University of Oxford, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.422670.
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Hodgson, Zoe G. "The role of steroid hormones in avian spatial learning and memory abilities." Thesis, University of Edinburgh, 2003. http://hdl.handle.net/1842/14082.
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I used the great tit (Parus major) and zebra finch (Taeniopygia guttata) as model species to determine whether steroid hormones have effects on avian spatial learning and memory. To address this I took a four-pronged approach: First, as spatial ability is to some extent reliant on appropriate cue use, I examined cue preference in the great tit. In a one-trial associative memory task birds were trained to a compound stimulus where both colour and location cues could be used to locate a reward. By dissociating the cues on probe trials I was able to determine which cues were controlling the birds’ food-finding behaviour. The overall distribution of choices was significantly different from random but did not differ between the sexes. Both sexes exhibited a preference for the location cue over the colour cue. Second, I exploited the existence of a well-characterised memory task that tests spatial and non-spatial memory. This was an operant conditioning delayed-non-matching-to-sample spatial memory task, presented on computer-controlled touch screen. I tested for sex differnces in performance in birds maintained under a breeding season (i.e. long-day) photoperiod. No sex differences in ability to perform either the spatial or visual memory task were found. Third, I used a non-invasive technique (oral administration) to manipulate hormone levels (testosterone (T), 5α-dihydrotesterone and oestradiol, the latter two being T metabolites) and determined their effect on learning and memory. Although T improved spatial learning and memory abilities in females in Experiment 1, no treatment effects were found in males or in Experiment 2. However, T increased response latencies (time taken to peck a touch screen image) in both sexes, suggesting a beneficial role of T on memory retention. My fourth approach was to use zebra finches selectively bred for differing peak (stress-induced) CORT levels to determine whether CORT affected avian spatial memory in a similar way to that seen in mammals.
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Stone, Erik E. Skubic Marge. "Adaptive temporal difference learning of spatial memory in the water maze task." Diss., Columbia, Mo. : University of Missouri--Columbia, 2009. http://hdl.handle.net/10355/6586.
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The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Title from PDF of title page (University of Missouri--Columbia, viewed on January 22, 2010). Thesis advisor: Dr. Marjorie Skubic. Includes bibliographical references.
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Lent, David D. "Learning and Memory and Supporting Neural Architecture in the Cockroach, Periplaneta americana." Diss., The University of Arizona, 2006. http://hdl.handle.net/10150/193804.
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The cockroach, with its large brain and physiological resilience, holds many advantages for the development of behavioral paradigms. The work presented here provides a foundation for, and describes the results of, the implementation of studies of neural correlates of learning and memory on restrained animals.Using the antennal projection response (APR) as an indicator of learning and retention, several learning paradigms have been developed. A visual-olfactory associative and a gustatory-olfactory aversive conditioning paradigm demonstrated a plastic behavior that could be driven in an intact and immobilized cockroach. Conditioning the APR to a visual cue paired with an olfactory cue characterized the role of unilateral and bilateral olfactory input in learning and memory. While unilateral olfactory input is sufficient to learn a visual-olfactory association, bilateral olfactory input is necessary for long-term retention of the association. This comparison identified a critical time period in which memory is consolidated. This time period was subsequently used to analyze gene expression during memory consolidation.The split-brain cockroach preparation was developed to investigate what parts of the brain are necessary and sufficient for learning and retention of a visual-olfactory association; this preparation was also used to examine learning-induced changes in test tissue versus control tissue provided by the same animal. Evidence suggests that half of a brain is sufficient for a visual-olfactory association to be established and sufficient for retention of that association between 12 and 24 hours. However, the entire brain is necessary for long-term memory to be established. Using the split-brain cockroach simultaneously as the control and the test subject, learning-induced alterations in the microglomerular synaptic complexes of the calyces were identified in the trained half, but not in the naïve half.Using the APR, spatial learning and memory was examined. Multiple representations of space were revealed in the brain of the cockroach. Cockroaches represent space in terms of an olfactory gradient map, as well as the visuospatial relationship between objects. When both representations of space can be utilized by the cockroach to localize a cue, the positional visual cue is the one that determines the behavioral response.
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MacLeod, Lindsey. "Visual Spatial Learning and Memory in Fragile X Syndrome and fmr1 Knockout Mice." Thesis, Université d'Ottawa / University of Ottawa, 2013. http://hdl.handle.net/10393/26001.
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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.
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Hunt, Peter Richard. "An examination of the effects of thalamic lesions on learning and memory in the rat." Thesis, Open University, 2000. http://oro.open.ac.uk/58058/.
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The study examined the effects of lesions of the thalamic nucleus medialis dorsalis (MD) made by neurotoxin in three cohorts ofrats to help understand the contribution of this nucleus to learning and memory. The lesions typically provided comprehensive damage to . MD, while the use of an excitotoxin helped to minimise damage to fibres of passage or adjacent fibre tracts. This excluded one confounding influence that may have been present in some previous studies. Some MD lesions also affected the anterior thalamic nuclei, and this additional damage led to spatial memory impairments, helping to confirm the value of results from rats with lesions confined to MD. Whilst the groups with MD lesions were largely unimpaired on non-spatial tests of visual recognition and discrimination, they were impaired on a configural discrimination task. The MD lesions did not impair spatial nonmatching to sample in aT-maze, nor the acquisition or performance over delay conditions of the standard radial maze task. There were impairments, however, when the radial maze was rotated during the delay, requiring a strategy shift. Similar impairment was found when a matching, rather than non-matching, strategy was required on the T-maze task and also when only some arms were rewarded on the radial arm maze task for reference memory measurement. No impairment was seen when the T-maze matching task was reversed to the non-matching variant, emphasising the lesion rats' preference for preexisting rules. In addition, some evidence was found that MD lesions brought about increased activity, but had no effect on conditioned place preference. The study concludes that MD damage in rats does not directly cause memory deficits. The influence that MD damage has on memory is, however, similar to that associated with damage to prefrontal cortex causing deficits in rule-switching ability, a higher order frontal lobe function.
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ABLE, JESSICA ANN. "MDMA ADMINISTRATION AFFECTS COGNITION IN THE RAT." University of Cincinnati / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1147890602.
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Coppola, Vincent Jesse. "Age-Related Impairment of Spatial Working Memory in Homing Pigeons (Columba livia)." Bowling Green State University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1399653220.
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Elvander, Tottie Elin. "Neurochemical regulators of the septohippocampal pathway : role in spatial and aversive learning /." Stockholm, 2006. http://diss.kib.ki.se/2006/91-7140-629-8/.
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Costanzo, Marna S. "Aspects of memory in the Damaraland mole-rat, Cryptomys damarensis spatial learning and kin recognition /." Diss., Pretoria : [s.n.], 2005. http://upetd.up.ac.za/thesis/available/etd-07032007-130259.
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Harloe, John Pinckney. "Endocannabinoid Modulation of Spatial Memory in Aversively and Appetitively Motivated Barnes Maze Tasks." VCU Scholars Compass, 2008. http://hdl.handle.net/10156/1555.
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Kahn, Meghan Cornelia. "Goal Location Memory in Pigeons: Roles of the Hippocampal Formation and Visual Wulst." Bowling Green, Ohio : Bowling Green State University, 2009. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=bgsu1242383665.
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Canova, Fernando 1980. "Aprendizagem de escolha alimentar em pombos (Columba livia) e imunorreação para as proteínas Zenk e sinapsina I no hipocampo : efeitos do antagonista de receptores GABAB, faclofeno." [s.n.], 2014. http://repositorio.unicamp.br/jspui/handle/REPOSIP/314124.
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Orientador: Elenice Aparecida de Moraes FerrariTese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia
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Resumo: A memória espacial tem importante valor para a sobrevivência do organismo. Está relacionada com sua habilidade em utilizar informações que possibilitam a formação de mapas espaciais de acordo com a relevância das relações entre as pistas ambientais. A memória espacial envolve alterações plásticas no hipocampo de roedores e de aves, dentre essas a indução da transcrição de genes de expressão imediata, tais como o zenk, que regula a expressão de inúmeros outros genes e proteínas. O gene zenk atua na regulação da expressão da proteína Sinapsina. A expressão de sinapsinas também parece estar relacionada com mecanismos sinápticos mediados por receptores GABAB. O presente trabalho teve como objetivo avaliar, em pombos, a aprendizagem, a consolidação e a persistência da memória espacial em situação de escolha alimentar. A plasticidade neural foi investigada pela análise da imunorreatividade para as proteínas Zenk e Sinapsina I no hipocampo. Foram realizados dois experimentos com pombos (Columba livia): No Experimento I foi avaliada a aprendizagem e memória espacial em animais submetidos ao treino de escolha alimentar em 2 ou 7 sessões de treino. Cada sessão teve 6 tentativas experimentais, numa arena circular com 4 comedouros onde apenas um tinha alimento. A resposta de escolha foi definida como orientar-se, aproximar-se e bicar um comedouro. Foi aplicado também o teste de estratégia espacial, que consistiu em 1 sessão, com 3 tentativas experimentais onde na terceira tentativa foram retirados os comedouros e os animais foram colocados na arena circular para análise do tempo de permanência no quadrante onde antes existia o comedouro com alimento. No Experimento II foram avaliados os efeitos do antagonista do receptor GABAB, faclofeno administrado (i.p) imediatamente após as sessões de treino. O teste de persistência da memória espacial foi realizado 7 dias após o treino. A análise imunoistoquímica foi utilizada para avaliação da expressão das proteínas Zenk e Sinapsina I no hipocampo. O número de escolhas corretas aumentou em função do treino, variando entre 50 e 88% na primeira e sétima sessões respectivamente (ANOVA, p < 0,001). O número de núcleos Zenk - positivos e células Sinapsina I - positivas aumentou no hipocampo de pombos treinados durante 7 sessões (ANOVA, p < 0,001). O tratamento com o inibidor do receptor GABAB teve um efeito facilitador nas sessões de treino em comparação com os grupos controles (ANOVA, p < 0,001). Os dados indicam que a experiência em escolha espacial desencadeia a ativação de mecanismos sinápticos que resultam na expressão de Zenk e Sinapsina I no hipocampo de pombos, os quais estão envolvidos na consolidação da memória espacial de escolha alimentar. Os efeitos do tratamento com faclofeno sugerem que o receptor GABAB participa destes mecanismos. Em conjunto os presentes dados demonstraram que o pombo é um modelo experimental importante para a análise de mecanismos de plasticidade neural no hipocampo que são conservados entre espécies de mamíferos e aves
Abstract: The spatial memory has important value for the organism's survival, because it is related with ability to acquire and use space information, enabling the formation of cognitive and spatial maps. The experience with the environment triggers behavioral, cellular and molecular changes in central nervous system that an essential to the formation and consolidation of spatial memory. Therefore, acquisition, consolidation and stability of spatial memory involve plastic changes in the hippocampus of rodents and birds, among these the induction of the expression of early gene transcription such as zenk gene which regulates the expression of numerous other genes and the proteins they control. The gene zenk acts in the formation of new memories and has a role in the regulation of the synapsin protein expression. The expression of synapsins also seems to be related with synaptic mechanisms mediated by the GABAB receptor. This study aimed to evaluate, in pigeons, consolidation and persistence of spatial memory in a situation of food location. The underlying neural plasticity was investigated through the analysis of immunoreactivity for Zenk and Synapsin I proteins in neurons of the hippocampus. Adult, male pigeons (Columba livia) were used in two experiments. Experiment I investigated learning and spatial memory during short (2 sessions) or long duration training (7 sessions). Sessions had 6 experimental trials and were conducted in a arena with 4 feeders. In each trial the bird was released at a different point of the arena, and the time between the release of the bird and the first feeder pecking response (latency of the choice response) was recorded. Testing for spatial strategy was conducted in the arena without any feeder and the time spent in each quadrant was analyzed. Experiment II analyzed the effects of the post-training administration of phaclofen on the consolidation and persistence of spatial memory. Testing of memory persistency occurred 7 days after the 7th training session. Immunohistochemistry of hippocampal tissue was used for the analysis of expression of Zenk and Synapsin I proteins. Number of correct choice increased across training, with values varying between 50 and 88% in the first and 7th session respectively (Anova, p < 0.001). Treatment with GABABantagonist had a facilitatory effect on choice performance which was indicated by lower latency values and higher accuracy values (Anova < 0.001). The values of Zenk positive and Synapsin I positive cells counting were higher in the hippocampus of pigeons that were trained during 7 days and in pigeons treated with phaclofen as compared to their respective controls (Anova p < 0.001). These data indicated that experience with spatial learning of food choice induced expression of Zenk and Synapsin I proteins in the hippocampus of pigeons during the consolidation of spatial memory. Post-training administration of phaclofen suggested a role of GABAB receptor in these experience-dependent synaptic mechanisms. The present results point to the pigeon as interesting animal model for the analysis of neuroplastic mechanisms involved with spatial memory, which are conservative across mammalian and birds species
Doutorado
Fisiologia
Doutor em Biologia Funcional e Molecular
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McFarlane, Gilbert John. "The Effects of Computer Versus Personal Administration on Measures of Verbal and Spatial Short-Term Memory." Thesis, North Texas State University, 1985. https://digital.library.unt.edu/ark:/67531/metadc331587/.
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This study sought to investigate the influence of expressive task demand, as determined by amount of face-to face social interaction, level of subjects' expressive ability, sex of subject, and sex of experimenter on subjects' digit and visual-spatial short-term memory span performance. The amount of personal contact was manipulated by the automated versus person administrations of the memory measures. The automated administration was accomplished through the use of a microcomputer.
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Hadzibegovic, Senka. "Behavioral, molecular and electrophysiological characterization of the learning and memory deficits induced in mouse models of Alzheimer’s disease." Thesis, Bordeaux, 2015. http://www.theses.fr/2015BORD0151/document.
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La maladie d’Alzheimer (MA) se caractérise par une perte des fonctions cognitives liée à une dégénérescence neuronale induite par l’accumulation de peptides amyloïdes-β (Aβs) dans des régions vulnérables du cerveau comme l’hippocampe. Au niveau moléculaire, les peptides Aβs se lient préférentiellement à la densité post-synaptique des synapses excitatrices, espace au niveau duquel la protéine d’échafaudage PSD-95 organise l’ancrage des récepteurs NMDA (RNMDAs) et régule leur mobilité membranaire. A l’aide d’une stratégie intégrative qui favorise des niveaux d’analyse verticaux (du phénotype aux événements moléculaires) et qui combine un ensemble d’approches corrélatives et invasives chez des souris double transgéniques APPswe/PS1dE9 modèles de la MA, nous avons mis en évidence que les peptides Aβs déstabilisent l’organisation synaptique (altération de l’expression de la PSD-95) et augmentent le pool extrasynaptique de sous-unités GluN2B des RNMDAs dans l’hippocampe. Cette réorganisation se traduit par une perturbation des fonctions mnésiques. Par ailleurs, il a été montré que certaines oscillations de l’activité hippocampique, comme les « sharp-wave ripples » (SWRs) générées pendant les périodes de sommeil, jouent un rôle crucial dans la formation de la mémoire. De façon surprenante, l’accumulation des peptides Aβs semble épargner la dynamique d’expression des SWRs durant les comportements de routine. Afin d’examiner l’effet potentiel des Aβs sur les SWRs chez des animaux confrontés à des challenges cognitifs, nous avons soumis des souris adultes injectées intracérébralement avec une solution d’Aβs à un test de reconnaissance spatiale. Alors qu’elles sont capables de former une mémoire à court terme, les souris Aβs montrent un oubli plus rapide, suggérant qu’elles encodent avec succès, mais qu’elles sont incapables de stabiliser et de rappeler une information acquise antérieurement. En l’absence d’une demande cognitive préalable, les propriétés des SWRs ne sont pas altérées par les Aβs. En revanche, lorsqu’elles doivent résoudre un test cognitif, les pics de SWRs normalement observés après encodage ou reconnaissance chez les souris témoins sont abolis chez les souris Aβs, indiquant une perturbation du traitement hippocampique de l’information spatiale. Pris dans leur ensemble, ces résultats identifient deux nouveaux mécanismes délétères sous-tendant les déficits de mémoire spatiale associés à la MACognitive impairments in Alzheimer’s disease (AD) are thought to be related to degenerative synaptic changes caused by the accumulation of amyloid-β peptides (Aβs) in vulnerable brain regions such as the hippocampus. At the molecular level, Aβs bind preferentially to the postsynaptic density of neuronal excitatory synapses, where the scaffolding post-synaptic protein-95 (PSD-95) organizes NMDA receptor (NMDAR) location as well as its downstream signaling. By using an integrative strategy which favoured vertical levels of analyses (from phenotype to molecular events) and combined a set of interrelated correlative and invasive approaches in a double transgenic mouse model of AD (APPswe/PS1dE9 mice), we were successful in establishing that Aβs destabilize the synaptic organization (reduction of expression of PSD-95) and increase the extrasynaptic pool of GluN2B-containing NMDAR in the hippocampus, a reorganization which translates into impaired memory functions. It is also well-known that hippocampal sharp wave-ripples (SWRs) generated during sleep periods are crucial for memory formation but accumulation of soluble Aβs, surprisingly seems to spare SWR dynamics during routine behavior. To unravel a potential effect of Aβs on SWRs in cognitively-challenged animals, we submitted vehicle- and Aβ-injected mice to spatial recognition memory testing. While capable of forming short-term memory, Aβ mice exhibited faster forgetting, suggesting successful encoding but an inability to adequately stabilize and/or retrieve previously acquired information. Without prior cognitive requirements, similar properties of SWRs were observed in both groups. In contrast, when cognitively challenged, the post-encoding and -recognition peaks in SWR occurrence observed in controls were abolished in Aβ mice, indicating impaired hippocampal processing of spatial information. Altogether these results identify two new disruptive mechanisms for the spatial memory deficits associated with AD
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曾凱玲 and Hoi-ling Tsang. "Learning a procedural task with animation: a comparison between the high and low visual spatial learners." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2003. http://hub.hku.hk/bib/B31227880.
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Click, Ivy A. "Gender Differences in Working Memory in Humans Tested on a Virtual Morris Water Maze." Digital Commons @ East Tennessee State University, 2005. https://dc.etsu.edu/etd/1052.
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A computerized virtual version of the Morris water maze (vMWM) was used to assess human gender differences in spatial working memory. In Experiment 1, the release point and platform location was changed on every other trial for 20 trials. Men had significantly reduced acquisition latencies and more accurate heading errors on the first daily trial compared to women. In Experiment 2, the release point and platform location was changed every fourth trial for 20 trials. Men had significantly shorter acquisition latencies and path lengths than women. Experiment 3 was identical to Experiment 2, except that environmental cues were changed throughout testing. Men had significantly shorter acquisition latencies and path lengths than did the women. These studies are the first to demonstrate significant gender differences in a spatial working memory version of the vMWM.
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SKELTON, MATTHEW RYAN. "EFFECTS OF NEONATAL 3,4-METHYLENEDIOXYMETHAMPHETAMINE ON HIPPOCAMPAL GENE EXPRESSION, SPATIAL LEARNING AND LONG-TERM POTENTIATION." University of Cincinnati / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1148067008.
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Sturesson, André. "Exercise-induced adult hippocampal neurogenesis and the effect of exercise and adult hippocampal neurogenesis on spatial learning and memory." Thesis, Högskolan i Skövde, Institutionen för biovetenskap, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:his:diva-15918.
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It was long believed within the scientific community that the adult brain was unable to generate new neurons. In the end of the 1990s the consensus changed and it is since believed that the adult brain can and does generate new neurons after birth, a process referred to as adult neurogenesis. Adult neurogenesis takes place in two places in the adult brain: the subventricular zone (SVZ) in close proximity to the olfactory bulb and the subgranular zone (SGZ) in the hippocampus. The level of adult hippocampal neurogenesis (AHN) can be upregulated and one part of the aim was to examine the effect of voluntary chronic aerobic exercise (VCAE) on AHN. It is clear that voluntary chronic aerobic exercise reliably increases AHN. Still, the function of these new brain cells is under debate. Spatial learning and memory are among the main abilities that have been focused on. The other part of the aim was to examine the effect of VCAE and AHN on spatial learning and memory. The reviewed literature suggests that both AHN and spatial learning and memory increase together from VCAE, although it does not show causation, that an increase of AHN from VCAE causally effects spatial learning and memory. More studies are needed to investigate if a causal relationship exists.
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Piber, Dominique [Verfasser]. "Effects of mineralocorticoid receptor stimulation on spatial learning and spatial memory in healthy young adults : a study using the virtual Morris Water Maze task / Dominique Piber." Berlin : Medizinische Fakultät Charité - Universitätsmedizin Berlin, 2017. http://d-nb.info/1127045725/34.
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Teixeira, Lívia Clemente Motta. "Exercício físico, neurogênese e memória." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/41/41135/tde-31032014-095131/.
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A neurogênese hipocampal é modulada por muitos fatores que incluem envelhecimento, estresse, enriquecimento ambiental, atividade física e aprendizado. Atividade física voluntária (espontânea) estimula a proliferação celular no giro denteado e facilita a aquisição e/ou retenção de tarefas dependentes do hipocampo, incluindo o Labirinto Aquático de Morris. Embora seja bem estabelecido que o exercício físico regular melhore o desempenho em tarefas de memória e aprendizado, não está claro qual a duração desses benefícios após o final da atividade física. Neste estudo investigamos a relação temporal entre os efeitos benéficos da atividade física associado ao aprendizado de tarefa dependente da função hipocampal, e sua relação com a neurogênese, levando em consideração também o tempo decorrido desde o término da atividade física. Grupos independentes de ratos tiveram acesso a roda de atividade ao longo de 7 dias (Grupo EXE) ou roda bloqueada (Grupo Ñ-EXE) e receberam injeções de BrdU nos últimos 3 dias de exposição roda. Após um INTERVALO de 1, 3 ou 6 semanas após o final da exposição a roda de atividade após o final da exposição a roda de atividade, os animais foram testados no labirinto aquático de Morris, sendo uma parte deles expostos a tarefa de memória operacional espacial, dependente da função hipocampal (H), e outra parte a uma tarefa de busca por uma plataforma visível, independente da função hipocampal (ÑH). Em ambos os casos, o intervalo entre as tentativas (ITI) foi de 10 minutos durante as sessões 1-6 e (virtualmente) zero minutos durante as sessões 7-10. Concluída a tarefa os cérebros foram processados para imuno-histoquímica. Foram feitas imunoistoquímicas para a detecção de Ki-67 (proliferação celular), BrdU, NeuN (para identificar neurónios maduros), e DCX (para identificar imaturo neurônios). Nossos dados suportam a ideia que atividade física voluntária induz um aumento na proliferação celular e na diferenciação neuronal (neurogênese) no giro denteado. A introdução de um período de intervalo entre o final do exercício e a execução da tarefa comportamental causa uma redução significativa na sobrevivência dos novos neurônios, como observado com 1 semana de intervalo em comparação com os animais testados com 6 semanas de intervalo. Em contraste, entretanto, o presente resultado não confirma que esse aumento da neurogênese é acompanhado por melhora na memória espacial, como avaliado por meio da versão que envolve memória operacional no labirinto aquático de Morris. O aprendizado da tarefa do labirinto aquático de Morris, na versão de memória operacional que é dependente do hipocampo, leva a um aumento da sobrevivência dos novos neurônios que foram produzidos no período de exercício, ao passo que o aprendizado da versão independente da tarefa leva a uma redução do número absoluto de novos neurôniosHippocampal adult neurogenesis is modulated by many factors including age, stress, environmental enrichment, physical exercise and learning. Spontaneous exercise in a running wheel stimulates cell proliferation in the adult dentate gyrus and facilitates acquisition and/or retention of hippocampal-dependent tasks including the Morris water maze. While it is well established that regular physical exercise improves cognitive performance, it is unclear for how long these benefits last after its interruption. In this study, we investigate the temporal relation between exercise-induced benefits associated with learning of a hippocampal-dependent task, this relationship with neurogenesis, considering the time after exercise has ended. Independent groups of rats were given free access to either unlocked (EXE Group) or locked (No-EXE Group) running wheels for 7 days, having received daily injections of BrdU for the last 3 days. The animals were then transferred to standard home cages. After a time period of either 1, 3 or 6 weeks, the animals were tested in the Morris water maze, one of them being exposed to the spatial working memory task dependent on hippocampal function (H) and partly to a task search for a visible platform, independent of hippocampal function (NH). In both cases, the interval between trials (ITI) was 10 minutes during sessions and 1-6 and (virtually) zero minute during the sessions 7-10. After the task brains were processed for immunohistochemistry. Cell proliferation and net neurogenesis were assessed in hippocampal sections using antibodies against BrdU, NeuN (to identify mature neurons), and DCX (to identify immature neurons). Data of the present study confirm that exposure of rats to 7 days of spontaneous wheel running increases cell proliferation and neurogenesis. In contrast, however, the present results did not confirm that this neurogenesis is accompanied by a significant improvement in spatial learning, as evaluated using the working memory version of the Morris’ water maze task. The introduction of a delay period between the end of exercise and cognitive training on the Morris water maze reduces cell survival; the number of new neurons was higher in the EXE1 week delay group as compared to the EXE6 week delay. We showed that learning the Morris water maze in the working memory task dependent on hippocampal function (H) increases the new neurons survival, in contrast, learning hippocampal-independent version of the task decreases number of new neurons
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Blair, Jeffrey A. "Luteinizing hormone in the central nervous system: a direct role in learning and memory." Kent State University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=kent1523397060445531.
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Weger, Ulrich Wolfgang. "Spatial and linguistic control of eye movements during reading." Diss., Online access via UMI:, 2005.
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Klur, Sandra. "Functional lateralization of spatial memory in the Rat : Experimental approach by gene expression profiling and by reversible inactivation of the dorsal hippocampus in a spatial learning task." Université Louis Pasteur (Strasbourg) (1971-2008), 2006. https://publication-theses.unistra.fr/public/theses_doctorat/2006/KLUR_Sandra_2006.pdf.
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Klur, Sandra Cassel Jean-Christophe Certa Ulrich. "Functional lateralization of spatial memory in the rat experimental approach by gene expression profiling and by reversible inactivation of the dorsal hippocampus in a spatial learning task /." Strasbourg : Université de Strasbourg, 2009. http://eprints-scd-ulp.u-strasbg.fr:8080/722/01/KLUR_Sandra_2006.pdf.
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Basu, Amrita. "Spatial Learning and Memory, Transcriptional and Proteomic Analysis of Growth Hormone Action in the Brain of bGH and GHA Mice." Ohio University / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1440073471.
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Tarou, Loraine Rybiski. "An examination of the role of associative learning and spatial memory in foraging in two species of bear (Family-Ursidae)." Diss., Available online, Georgia Institute of Technology, 2004:, 2003. http://etd.gatech.edu/theses/available/etd-04082004-180438/unrestricted/tarou%5floraine%5fr%5f200312%5fphd.pdf.
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Schurman, Lesley D. "Spatial learning and memory in brain-injured and non-injured mice: investigating the roles of diacylglycerol lipase-α and -β." VCU Scholars Compass, 2018. https://scholarscompass.vcu.edu/etd/5662.
Full textAbstract:
A growing body of evidence implicates the importance of the endogenous cannabinoid 2-arachidonyl glycerol (2-AG) in memory regulation. The biosynthesis of 2-AG occurs primarily through the diacylglycerol lipases (DAGL-α and -β), with 2-AG serving as a bioactive lipid to both activate cannabinoid receptors and as a rate limiting precursor for the production of arachidonic acid and subsequent pro-inflammatory mediators. Gene deletion of DAGL-α shows decrements in synaptic plasticity and hippocampal neurogenesis suggesting this biosynthetic enzyme may be important for processes of normal spatial memory. Additionally, 2-AG is elevated in response to pathogenic events such as traumatic brain injury (TBI), suggesting its regulatory role may extend to conditions of neuropathology. As such, this dissertation investigates the in vivo role of DAGL-α and -β to regulate spatial learning and memory in the healthy brain and following neuropathology (TBI).
The first part of this dissertation developed a mouse model of learning and memory impairment following TBI, using hippocampal-dependent tasks of the Morris water maze (MWM). We found modest, but distinct differences in MWM performance between left and right unilateral TBI despite similar motor deficits, histological damage, and glial reactivity. These findings suggest that laterality in mouse MWM deficit might be an important consideration when modeling TBI-induced functional consequences. The second part of this dissertation work evaluated DAGL-β as a target to protect against TBI-induced learning and memory deficit given its selective expression on microglia and the role of 2-AG as a precursor for eicosanoid production. The gene deletion of DAGL-β did not protect against TBI-induced MWM or motor deficits, but unexpectedly produced a survival protective phenotype. These findings suggest that while DAGL-β does not contribute to injury-induced memory deficit, it may contribute to TBI-induced mortality. The third and final set of experiments investigated the role of DAGL-α in mouse spatial learning and memory under physiological conditions (given the predominantly neuronal expression of DAGL-α). Complementary pharmacological and genetic manipulations produced task specific impaired MWM performance, as well as impaired long-term potentiation and alterations to endocannabinoid lipid levels. These results suggest that DAGL-α may play a selective role in the integration of new spatial information in the normal mouse brain.
Overall, these data point to DAGL-α, but not DAGL-β, as an important contributor to hippocampal-dependent learning and memory. In contrast, DAGL-β may contribute to TBI-induced mortality.
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Manganaro, Alessia. "Functional differentiation along the dorso-ventral axis of the hippocampus." Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:a7b47ea6-d9f4-4999-a0be-12980ea81d90.
Full textAbstract:
The hippocampus plays an important role in the processing of spatial memory. During exploration, theta oscillations (4-12 Hz) are prominent in the hippocampus, whereas during sleep and rest irregular sharp wave/ripple (SWR) events occur spontaneously in the hippocampus and may support memory consolidation. To date, the ventral sub-region of the rodents hippocampus, has received less attention relative to the more accessible dorsal part. It has been suggested that spatial information decreases along the septo-temporal axis in favour of coding salient features and coordinated oscillatory activity might enable the binding of spatial and nonspatial information. The first goal of my research was to investigate how the spatial representation by dorsal and ventral neurons is organised by theta oscillations in the hippocampal network. The second goal was to investigate the role of the ventral hippocampus in spatial learning. Finally, the third goal examined to what extent the firing relationships established during spatial learning are replayed during subsequent sleep in the ventral CA1. I recorded the network activity of dorsal and ventral CA1 in rats performing a spatial memory task on the cheese board maze (Dupret et al., 2010). By using parallel multi-channel extracellular recordings in the dorsal and ventral portions of the hippocampus in behaving rats, I found that dorsal and ventral CA1 were theta coupled at particular times of the spatial learning. High coherence periods across the two regions were characterized by a strong speed-modulation of ventral theta oscillations, which was absent in other conditions. During sleep, it was found that SWR-related activity was presented in the ventral hippocampus as well, when the coordinated population activity established in spatial learning was reactivated within the two sub-regions. By contrast, reactivation across the two regions was observed outside the SWRs epochs. Overall, the data suggests that the ventral hippocampus might be involved in the processing of salient features of the environment such as rewards. On a temporal scale, this non-spatial information might be integrated to the spatial information provided by the dorsal hippocampus during theta oscillation. During sleep/rest periods, the coordinated communication of learned information might underlie the consolidation of memory traces.
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Sizemore, Brittany A. "Time-of-Day Associative Learning to Spatial or Feature Information in Homing Pigeons (Columba livia)." Bowling Green State University / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1447777465.
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Ragan, Eric Dennis. "Supporting Learning through Spatial Information Presentations in Virtual Environments." Diss., Virginia Tech, 2013. http://hdl.handle.net/10919/23207.
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Though many researchers have suggested that 3D virtual environments (VEs) could provide advantages for conceptual learning, few studies have attempted to evaluate the validity of this claim. While many educational VEs share the challenge of providing learners with information within 3D spaces, few researchers have investigated what approaches are used to help learn new information from 3D spatial representations. It is not understood how well learners can take advantage of 3D layouts to help understand information. Additionally, although complex arrangements of information within 3D space can potentially allow for large amounts of information to be presented within a VE, accessing this information can become more difficult due to the increased navigational challenges.Complicating these issues are details regarding display types and interaction devices used for educational applications. Compared to desktop displays, more immersive VE systems often provide display features (e.g., stereoscopy, increased field of view) that support improved perception and understanding of spatial information. Additionally, immersive VE often allow more familiar, natural interaction methods (e.g., physical walking or rotation of the head and body) to control viewing within the virtual space. It is unknown how these features interact with the types of spatial information presentations to affect learning.
The research presented in this dissertation investigates these issues in order to further the knowledge of how to design VEs to support learning. The research includes six studies (five empirical experiments and one case study) designed to investigate how spatial information presentations affect learning effectiveness and learner strategies. This investigation includes consideration for the complexity of spatial information layouts, the features of display systems that could affect the effectiveness of spatial strategies, and the degree of navigational control for accessing information. Based on the results of these studies, we created a set of design guidelines for developing VEs for learning-related activities. By considering factors of virtual information presentation, as well as those based on the display-systems, our guidelines support design decisions for both the software and hardware required for creating effective educational VEs.
Ph. D.
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Costa, Valeria Catelli Infantozzi da. "Lesão seletiva do giro denteado do hipocampo e o desempenho de ratos em tarefas espaciais e temporais." Universidade de São Paulo, 1997. http://www.teses.usp.br/teses/disponiveis/47/47135/tde-21102008-155752/.
Full textAbstract:
Na literatura encontram-se propostas acerca da função do hipocampo como mediador (1) da memória operacional (working memory) e/ou como responsável pelo processamento de informações espacias e (2) de processos de controle temporal. Avaliou-se os efeitos da lesão seletiva do giro denteado, por aplicação múltipla e tópica de colchicina, no desempenho de ratos previamente treinados em tarefas que envolvem discriminação espacial e controle temporal. Experimento I: Os animais foram submetidos a uma tarefa de non-matchingto- sample (NMTS) em um labirinto em MAIS. Nesta tarefa, em uma primeira fase (fase de informação), o reforço é colocado somente em uma das caixas localizadas no final dos braços transversais - o acesso à outra caixa é bloqueado. Na segunda fase (fase de escolha), o acesso às duas caixas transversais é liberado e o reforço é colocado somente na caixa que não estava previamente disponível durante a fase de informação. Desta forma, os animais devem manter a informação do local previamente reforçado na 1a. fase; além disso, a informação de uma tentativa não pode ser generalizada para as tentativas subsequêntes. Estes mesmos animais foram treinados em uma tarefa temporal realizada em uma caixa de Skinner em um esquema de DRL - Differential Reinforcement of Low Rates. Neste procedimento, a resposta (pressão à barra) é reforçada se, e somente se, ela segue a resposta precedente por um intervalo de tempo específico, no caso, um intervalo de 20 segundos. Na tarefa espacial, embora haja um prejuízo na taxa de re-aquisição da resposta, o treino repetitivo faz com que o desempenho dos animais lesados se equipare aos dos sham. Estes resultados podem ser devidos à recuperação da capacidade de processar informações espaciais, ou então, à utilização de outra estratégia. Na tarefa temporal (DRL) os animais lesados continuam sendo capazes de espaçar suas respostas por um determinado intervalo, porém esse tempo é subestimado, ou seja, a pressão à barra ocorre em um tempo menor que o previamente treinado. Esta alteração no processamento de informações temporais pode dever-se a: a. deficiência no relógio interno - aceleração na contagem do tempo ou, b. deficiência no armazenamento de informações temporais - lembrança de um evento como se ocorresse antes do que de fato ocorre ou, c. porque os animais lesados são incapazes de evitar a pressão à barra, supondo-se que o desempenho deles, inclusive dos animais sham, esteja baseado em uma estratégia espacial de deslocamento na caixa experimental. Experimento II: A seguir, os animais foram testados em uma tarefa de delayed-non-matching-to-sample (DNMTS). Este procedimento é igual ao anterior, com a diferença da introdução de intervalos de 1, 2, 4, 8 e 16 minutos, entre as fases de informação e de escolha. Quando são introduzidos intervalos entre as fases, os animais lesados voltam a apresentar um prejuízo de desempenho com relação aos animais sham. Experimento III: Os sujeitos e equipamento empregados foram os mesmos utilizados no Experimento I e II. Neste experimento, os animais, na fase de escolha, ao invés de saírem da caixa inicial, saíram da caixa da qual acabaram de visitar na fase de informação. Se os animais estivessem utilizando uma estratégia de orientação egocêntrica, então eles deveriam virar à esquerda ou à direita, porém os animais seguiram em frente, dirigindo-se para a caixa alvo. Os resultados obtidos neste teste sugerem que os animais lesados estariam utilizando-se de uma estratégia espacial ou visual para resolverem a tarefa. Com esses resultados pode-se descartar a hipótese de que a recuperação de desempenho dos animais lesados esteja associada à utilização de uma estratégia de orientação egocêntrica; contudo, não pode-se descartar a hipótese da utilização de pistas (estratégia por guiamento).The effects of multiple-site, intradentate, colchicine injections on the performance of a temporal, differential reinforcement of low rates of responding (DRL-20 s) task and a spatial, delayed non-matching-to-place (DNMTP) task in a plus-maze were investigated in rats trained in both tasks prior to the lesion. Quantitative analysis revealed a greater than 86% reduction in the dentate gyrus (DG) of the colchicine-injected rats compared to the sham-operated controls. Dentate gyrus damage rendered rats less efcient than sham-operated controls in the performance of the DRL-20 s task. The DRL inter-response time (IRT) distribution for the DG-lesioned rats and the sham-operated controls was similar; however, while the distribution peak for the control rats was 20 s, it was 16 s for the DG-lesioned rats, indicating that the latter rats underestimated time. Performance of the DG-lesioned rats was also disrupted in the DNMTP task. However, DG-lesioned rats recovered control levels of performance during repeated training with an intertrial interval equal to 3 s. An increase in intertrial interval in lesioned and sham-operated controls disrupted performance in both groups; however, while DG-lesioned rats performed at chance levels when the intertrial interval was increased to 4 min or longer, the sham-operated controls performed at chance levels only when the intertrial interval was increased to 16 min. These results seem most parsimoniously interpreted following the cognitive map theory of hippocampal function.
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Dursun, Ilknur. "Effects Of Prenatal Alcohol Exposure On Activity, Anxiety And Learning In Young Adult Wistar Rats." Master's thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/3/12605930/index.pdf.
Full textAbstract:
The objective of the present study was to examine the effects of prenatal exposure
to alcohol on sensorimotor coordination, emotionality, learning and memory in
young adult Wistar rats. Most of the recent reports concerning behavioral effects of
fetal alcohol exposure refer to the juvenile period of life and very few studies
investigated different aspects of behavior simultaneously in the same subjects. In
the current study, alcohol was delivered to the pregnant dams by intragastric
infusions, throughout gestation days (GD) 7-20, at the dose of 6g /kg maternal body
weight /day. This dose resulted in relatively high peak blood alcohol concentration
(340 mg/dl) as assessed on GD 20. A pair-fed isocaloric and untreated control
groups were included. Prenatal alcohol administration retarded dams&rsquoweight gain significantly, and had an adverse effect on pups&rsquo
weight at birth but not in adulthood. No between-group differences were observed in the litter size and in the pups&rsquo
mortality. The adult brain weight was neither affected. Pups were subjected to a series of behavioural tests as young adults (at 2.5 months of age). In adulthood, rats prenatally treated with alcohol were not impaired in sensorimotor coordination and/or did not show muscle weakness as assessed by rotarod/accelerod tests. Their behavior in the open field and plus maze suggested alcohol-induced increase in iv anxiety level and some decrease in behavioral flexibility, but hyperactivity was not observed. In cognitive tasks, alcohol treated rats showed slightly slower rate of initial place learning in the water maze. However, memory retention tested after 1 and 10-day delay, reversal learning, rate of extinction of place preference, as well as working memory capacity appeared to be the same in alcohol exposed and control rats. The possible reasons of this negative result are discussed.
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Brown-Strittholt, Carrie Ann. "Interaction of Brain Derived Neurotrophic Factor and the HPA Axis Stress Response System with Neonatal d-Methamphetamine Induced Spatial Learning and Memory Deficits." University of Cincinnati / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1116173412.
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Brown-Strittholt, Carrie A. "Interaction of brain derived neurotrophic factor and the HPA axis stress response system with neonatal d-methamphetamine induced spatial learning and memory deficits." Cincinnati, Ohio : University of Cincinnati, 2005. http://rave.ohiolink.edu/etdc/view.cgi?acc_num=ucin1116173412.
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Jun, Jaeyoon James. "Memory-guided Sensory Sampling During Self-guided Exploration in Pulse-type Electric Fish." Thesis, Université d'Ottawa / University of Ottawa, 2014. http://hdl.handle.net/10393/31496.
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Animals must sense their surroundings to update their internal representations of the external environment, and exploratory behaviours such as sensory sampling are influenced by past experiences. This thesis investigates how voluntary sensory sampling activities undergo learning-dependent changes. Studies of freely behaving animals impose two major challenges: 1) the accuracy of biological measurements is compromised by movement-induced artifacts, and 2) large degrees of freedom in unrestrained behaviours confound well-controlled studies. Pulse-type weakly electric fish (WEF) are an ideal choice to study adaptive sensory sampling from unrestrained animals, since they generate readily observable and quantifiable sensory capture events expressed by discrete pulses of electric organ discharges (EODs). To study the voluntarily movements and sensory sampling while animals navigated in darkness, we developed three novel experimental techniques to track movements and detect sensory sampling from a freely behaving WEF: 1) an EOD detector to remotely and accurately measure the sensory sampling rate, 2) an electrical tracking method to track multiple WEF using their own EODs, and 3) visual tracking algorithm for robust body tracking through water under infrared illumination. These techniques were successfully applied to reveal novel sensory sampling behaviours in freely exploring Gymnotus sp. Cortical activity precedes self-initiated movements by several seconds in mammals; this observation has led into inquiries on the nature of volition. Here we demonstrate the sensory sampling enhancement also precedes self-initiated movement by a few seconds in Gymnotus sp. Next, we tested whether these animals can be trained to learn a location of food using electrically detectable landmarks and, if so, whether they can use their past experiences to optimize their sensory sampling. We found that animals revisited the missing food location with high spatial accuracy, and they intensified their sensory sampling near the expected food location by increasing the number of EOD pulses per unit distance travelled.
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Lai, Yu-Ting. "The effect of prenatal stress exposure on cognitive function in later life in rats." Thesis, University of Edinburgh, 2016. http://hdl.handle.net/1842/25876.
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Prenatal stress exposure (PNS) has detrimental effects on the offspring’s brain and behaviour and has been identified as an etiological factor in inducing cognitive function deficits in rodents and humans. The neural mechanisms are unclear, however reprogramming of the neuroendocrine stress axis, the hypothalamo-pituitary- adrenal (HPA) axis is hypothesised. A psychosocial stressor (residentintruder paradigm) was used to generate PNS rat offspring, making these studies clinically compatible. The hippocampus and the medial prefrontal cortex (mPFC) are critical in regulating cognitive function and also contribute to the negative feedback control of the HPA axis via corticosteroid receptors, including the mineralocorticoid receptor (MR) and the glucocorticoid receptor (GR). Here the Barnes maze was used to assess spatial learning and memory in male and female PNS offspring during adulthood under different scenarios, including basal and acute and chronic stress conditions. Under basal conditions, PNS was associated with reduced GR and MR mRNA expression in the medial prefrontal cortex (mPFC) and the hippocampus, respectively; suggesting inhibitory feedback control of the HPA axis may be compromised in PNS rats. Moreover, impaired spatial learning was observed in male PNS rats following acute restraint stress. Bilateral lesions of the prelimbic cortex and central administration of an MR antagonist in control rats suggested acute stress-induced learning deficits in PNS males were a result of impaired hippocampus-mediated inhibitory feedback control of the HPA axis. Conversely, a one-week variable stress regimen facilitated spatial learning in PNS rats and this was associated with elevated MR mRNA expression in the dentate gyrus. Moreover, facilitated learning in the PNS rats exposed to chronic stress could be blocked by central administration of an MR antagonist, indicating a facilitatory role of hippocampal MR in spatial learning. In summary, opposite effects of PNS on spatial learning were observed under acute and chronic stress conditions, in which hippocampal MR played a key role in regulating behavioural performance. The effect of age was also examined in PNS rats, and the findings from middle-aged (10-11 months old) rats indicated PNS may accelerate cognitive decline. Sex differences were also studied, with control females’ out-performing males under basal conditions in terms of spatial learning and behavioural flexibility; however following prenatal or chronic stress these sex differences were no longer detected. Furthermore, acute stress impaired spatial learning to a greater extent in females, and this might be attributed to greater HPA axis responses to stress in females compared with males. In conclusion, prenatal stress alters later cognitive performance, in a sex- and stress context-dependent manner. Hippocampal MR plays a critical role in mediating spatial learning, particularly during stress conditions.
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Elibol, Birsen. "Effects Of Chronic Ethanol Consumption On Memory And Molecular Changes In The Hippocampus Of Young Adult Wistar Rats." Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/3/12608891/index.pdf.
Full textAbstract:
The aim of the present study was to examine retention of spatial reference memory after 6 (Experiment I) and 15days (Experiment II) of binge-like drinking and during alcohol withdrawal in young adult Wistar rats. Prior to alcohol treatment, rats received Morris Water Maze (MWM) training. Afterwards, rats were intragastrically administered ethanol at the dose increasing from 4.5g-to-12g/kg. Intubation control groups (n=7 and n=10, respectively) received infusions of a sucrose solution without ethanol. Subsequently, all subjects were given a single probe trial in the MWM to test memory retention. In both experiments, there were three alcohol groups: A0 group (n=7) tested 4h after the last alcohol administration for acute effects of ethanolA24 group (n=7) tested 24h after alcohol cessation, when acute ethanol effects disappear but withdrawal symptoms does not develop yet
A72 group (n=7) tested 72h after the last ethanol infusion for withdrawal effects. Finally, potential molecular changes in hippocampus were examined using Fourier Transform Infra-Red (FT-IR) spectroscopy. The blood alcohol concentration was 605.67±
36mg/dl. In Experiment I, due to the low overall level of performance in the memory retention task the behavioral effects of ethanol could not be evaluated and no significant between&ndash
group differences were observed in Experiment II. In Experiment I, no significant changes in the molecular make-up of the hippocampus were noted. Conversely, in Experiment II, significant changes in protein, lipid, and nucleic acid profiles related to ethanol intake and withdrawal were found. They are linked to both development of tolerance to ethanol and adverse withdrawal effects.
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Yetimler, Berrak. "Investigation Of The Potential Correlation Between The Cognitive Performance And Levels Of Brain Fatty Acids In Young And Aged Mice." Master's thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12613090/index.pdf.
Full textAbstract:
The aim of the present study was to elucidate the possible relationship between
the levels of various brain fatty acids and learning indices in aged and young mice
classified as &ldquogood&rdquo
or &ldquo
poor&rdquo
learners basing on their performance in a spatial learning task, the Morris Water Maze. The levels of several fatty acids including palmitic, stearic, oleic, linoleic, arachidonic acid (AA) and docosahexaenoic acid (DHA) were measured using gas chromatography separately in samples from four different brain areas: hippocampus, cortex, striatum and hypothalamus. The level of oleic acid in the cerebral cortex was significantly higher in young-good learners as compared to young-poor learners and higher in young-poor learners than in old-poor learners, with no significant difference in the concentration of this acid between old-good and old-poor learners. The most consistent correlation between animals&rsquo
learning capacity and brain fatty acid&rsquo
level was found for the arachidonic acid in the hippocampal region: AA level was significantly lower in young-good learners as compared to both young-poor learners&rdquo
and old-good learners&rdquo
with young-good learners showing significantly better performance than the two other groups. Interestingly, except hypothalamus, no significant between-group differences were recorded for the remaining fatty acids including DHA, in none of the four brain regions examined.
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Johnson, Patricia R. "A Confirmatory Factor Analysis of WRAML Scores in a Group of Academically Talented Students." Thesis, University of North Texas, 2000. https://digital.library.unt.edu/ark:/67531/metadc2716/.
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The purpose of this study was to confirm the original factor structure of the Wide Range Assessment of Memory and Learning (WRAML) utilizing a non-clinical adolescent population. Additional analysis examined the relationship between SAT-M scores and spatial relations ability. Exploratory analyses were conducted to determine ethnic and gender differences on the WRAML and subtests from the DAT. Sixty-four academically talented adolescents completed the WRAML and the mechanical reasoning and spatial relations subtests from the Differential Aptitude Test (DAT). The confirmatory factor analysis found the data obtained to not be a good fit for the factor structure of the WRAML (Sheslow & Adams, 1990). Additional confirmatory analyses were conducted which examined data fit of a three factor model found by reanalyzing the standardization data (Burton et al., 1996; Wasserman & Cambias, 1991) as well as two null models. The data failed to fit any of these three models. No support was found for the second hypothesis that predicted a positive relationship between SAT-M scores and spatial relations ability. Ethnic and gender differences on the WRAML and two DAT subtests were examined and discussed. Limitations of this study were reviewed which may have accounted for the overall lack of results.
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Coppola, Vincent Jesse. "Neurocognitive aging in homing pigeons (Columba livia):Further investigation into hippocampal-dependent memory impairment and testing of the cholinergic hypothesis of cognitive decline." Bowling Green State University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1553609743315119.
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Xie, Jeanne Yan. "The effect of development on spatial pattern separation in the hippocampus as quantified by the Homer1a immediate-early gene." Thesis, Lethbridge, Alta. : University of Lethbridge, Dept. of Neuroscience, c2013, 2013. http://hdl.handle.net/10133/3414.
Full textAbstract:
This study sought to determine whether the DG, CA3, and CA1 regions contain
uniformly excitable populations and test the hypothesis that rapid addition of new, more
excitable, granule cells in prepubescence results in a low activation probability (P1) in the
DG. The immediate-early gene Homer1a was used as a neural activity marker to quantify
activation in juvenile (P28) and adult (~5 mo) rats during track running. The main finding
was that P1 in juveniles was substantially lower not only the DG, but also CA3 and CA1.
The P1 for a DG granule cell was close to 0 in juveniles, versus 0.58 in adults. The low P1
in juveniles indicates that sparse, but non-overlapping, subpopulations participate in
encoding events. Since sparse, orthogonal coding enhances a network’s ability to
decorrelate input patterns (Marr, 1971; McNaughton & Morris, 1987), the findings
suggest that juveniles likely possess greatly enhanced pattern separation ability.ix, 51 leaves : ill. ; 29 cm
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Florian, Cédrik. "Approches comportementales, pharmacologiques et moléculaires de l'étude de la région CA3 de l'hippocampe dorsal dans les apprentissages et les processus de consolidation de la mémoire spatiale." Toulouse 3, 2005. http://www.theses.fr/2005TOU30050.
Full textAbstract:
Cette thèse s'inscrit dans le cadre de la recherche sur les supports nerveux des activités cognitives liées à la connaissance de l'espace, et dans les formes de plasticité qui sont à la base de ces processus mnésiques. Comme de nombreux modèles computationnels confèrent à la région CA3 de l'hippocampe dorsal un rôle dans la mémoire spatiale et dans les processus de navigation, nous avons focalisé notre recherche sur cette région chez la souris C57BL/6. L'ensemble des résultats a montré que cette région est impliquée dans l'acquisition et surtout dans le traitement d'une information spatiale lors de la consolidation mnésique mais pas lors de la phase de rappel. De plus, ces études ont montré que les facteurs de transcription CREB, et les molécules d'adhésion cellulaire (PSA-NCAM) sont impliqués lors de la consolidation mnésique d'une information spatiale, certainement en agissant sur des modifications ou des réorganisations synaptiques au niveau de cette région CA3This work comes within the framework of research on the nervous support of cognitive activities in relation to the knowledge of the space, as well as the forms of plasticity which are the basis of these memory processes. This research work was focused on the dorsal hippocampal CA3-region study in C57BL/6 mouse because many computational models confer to this region a role in spatial memory and navigation processes. The combined results showed that this area is involved in the acquisition and particularly in the treatment of spatial information occuring memory consolidation, but not in the recall phase. Moreover, these studies showed that both CREB transcription factors and cellular adhesion molecules (PSA-NCAM) are involved during spatial memory consolidation, certainly by acting on synaptic modifications or reorganization in the CA3-region
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Lee, Aletheia. "Site-directed monoclonal antibodies : developing a tool for manipulating AMPA-type ionotropic glutamate receptor subunits in the mouse brain." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:aa83582e-d096-4b0b-be6f-55a74fb16014.
Full textAbstract:
Ionotropic glutamate AMPA-type receptors mediate fast excitatory neurotransmission in the central nervous system and are essential for synaptic plasticity. Expression of the receptor subunits varies with cell type, stage of development and brain region. Subunit composition determines functional properties of the receptor, including gating kinetics and synaptic trafficking. The research aimed to selectively disrupt the GluA1 subunit abundantly expressed in the hippocampus of the wild-type mouse, so as to examine its role in learning and memory. Site-directed monoclonal antibodies were engineered to target the extracellular amino-terminal domain of GluA1 for subunit-selective manipulation. The antibody-binding region was selected for heterogeneity and accessibility based on the amino acid sequences and crystal structures solved for the AMPA receptor subunits. Immunisations of peptide antigen in mice generated serum antibodies that recognise the equivalent epitope on the fully folded GluA1 subunit. The antigen-binding Fab fragment of the monoclonal anti-GluA1 antibody was cloned from hydridoma mRNA and purified from large-scale transient expression in mammalian cells. Biophysical characterisations of anti-GluA1 Fab immunoglobulin showed high specificity and affinity for the target subunit. Acute bilateral intrahippocampal administration of anti-GluA1 Fab protein into awake, behaving wild-type mice produced dissociations in spatial memory performance that resembled GluA1-/- knockout mice. Impaired short-term spatial working memory but intact long-term spatial reference memory observed with anti-GluA1 Fab infusions suggested that the immunoglobulin reagent exerted an acute, reversible, localised, GluA1-specific antagonism in the brain. The findings argue for a critical involvement of the hippocampal GluA1 subunit in certain short-term memory processes, but not in other distinct long-term memory processes. Temporal resolution of the antibody-mediated disruption revealed novel fractionations of short-term memory performance never before observed in the GluA1-/- knockout mice, demonstrating the strength of the monoclonal anti-GluA1 antibodies as an investigative tool.
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Auffarth, Benjamin. "Machine Learning Techniques with Specific Application to the Early Olfactory System." Doctoral thesis, KTH, Beräkningsbiologi, CB, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-90474.
Full textAbstract:
This thesis deals with machine learning techniques for the extraction of structure and the analysis of the vertebrate olfactory pathway based on related methods. Some of its main contributions are summarized below. We have performed a systematic investigation for classification in biomedical images with the goal of recognizing a material in these images by its texture. This investigation included (i) different measures for evaluating the importance of image descriptors (features), (ii) methods to select a feature set based on these evaluations, and (iii) classification algorithms. Image features were evaluated according to their estimated relevance for the classification task and their redundancy with other features. For this purpose, we proposed a framework for relevance and redundancy measures and, within this framework, we proposed two new measures. These were the value difference metric and the fit criterion. Both measures performed well in comparison with other previously used ones for evaluating features. We also proposed a Hopfield network as a method for feature selection, which in experiments gave one of the best results relative to other previously used approaches. We proposed a genetic algorithm for clustering and tested it on several realworld datasets. This genetic algorithm was novel in several ways, including (i) the use of intra-cluster distance as additional optimization criterion, (ii) an annealing procedure, and (iii) adaptation of mutation rates. As opposed to many conventional clustering algorithms, our optimization framework allowed us to use different cluster validation measures including those which do not rely on cluster centroids. We demonstrated the use of the clustering algorithm experimentally with several cluster validity measures as optimization criteria. We compared the performance of our clustering algorithm to that of the often-used fuzzy c-means algorithm on several standard machine learning datasets from the University of California/Urvine (UCI) and obtained good results. The organization of representations in the brain has been observed at several stages of processing to spatially decompose input from the environment into features that are somehow relevant from a behavioral or perceptual standpoint. For the perception of smells, the analysis of such an organization, however, is not as straightforward because of the missing metric. Some studies report spatial clusters for several combinations of physico-chemical properties in the olfactory bulb at the level of the glomeruli. We performed a systematic study of representations based on a dataset of activity-related images comprising more than 350 odorants and covering the whole spatial array of the first synaptic level in the olfactory system. We found clustered representations for several physico-chemical properties. We compared the relevance of these properties to activations and estimated the size of the coding zones. The results confirmed and extended previous studies on olfactory coding for physico-chemical properties. Particularly of interest was the spatial progression by carbon chain that we found. We discussed our estimates of relevance and coding size in the context of processing strategies. We think that the results obtained in this study could guide the search into olfactory coding primitives and the understanding of the stimulus space. In a second study on representations in the olfactory bulb, we grouped odorants together by perceptual categories, such as floral and fruity. By the application of the same statistical methods as in the previous study, we found clustered zones for these categories. Furthermore, we found that distances between spatial representations were related to perceptual differences in humans as reported in the literature. This was possibly the first time that such an analysis had been done. Apart from pointing towards a spatial decomposition by perceptual dimensions, results indicate that distance relationships between representations could be perceptually meaningful. In a third study, we modeled axon convergence from olfactory receptor neurons to the olfactory bulb. Sensory neurons were stimulated by a set of biologically-relevant odors, which were described by a set of physico-chemical properties that covaried with the neural and glomerular population activity in the olfactory bulb. Convergence was mediated by the covariance between olfactory neurons. In our model, we could replicate the formation of glomeruli and concentration coding as reported in the literature, and further, we found that the spatial relationships between representational zones resulting from our model correlated with reported perceptual differences between odor categories. This shows that natural statistics, including similarity of physico-chemical structure of odorants, can give rise to an ordered arrangement of representations at the olfactory bulb level where the distances between representations are perceptually relevant.QC 20120224
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Cara, Michel. "Stratégies d'apprentissage de la lecture musicale à court-terme : mémoire de travail et oculométrie cognitive." Thesis, Dijon, 2013. http://www.theses.fr/2013DIJOL013.
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Tout au long de cette thèse, l’évaluation musicale est traitée comme un objet d’étude latent visant à donner des outils pour l’apprentissage de la lecture musicale. Grâce à l’analyse des mouvements oculaires et les variables provenant de la performance, nous avons défini certaines variables qui rendent compte de l’expertise et des interactions entre différents groupes de niveaux d’expertise musicale lors de l’apprentissage d’un nouveau morceau de musique. De façon plus détaillée, nous avons observé la mise en œuvre de différentes stratégies de prise d’information, de traitement et de récupération de l’information musicale en fonction du niveau pianistique et souligné l’importance d’apprendre en interaction avec la classe et le professeur. Les stratégies sont en même temps ajustées par rapport à la confiance acquise au cours du processus d'acquisition de compétences (Bandura, 1997 ; McPherson et McCormick, 2006). En référence au débat actuel concernant la nature de la lecture de partitions, nous avons comparé les traitements musicaux et verbaux pendant une tâche de lecture « compréhensive » de textes et de partitions. Dans l’ensemble et au regard du modèle de Baddeley (1990), les ressources cognitives des musiciens pendant la lecture musicale seraient mobilisées en fonction de l’expertise et du type de style musicalThroughout this thesis, evaluation of music performance is viewed as a latent object of study in order to provide tools for learning to read music. We have defined some variables from eye movements and music performance accounting for expert performance and interactions between skill groups when learning a new piece of music. In more details, we have observed the use of different strategies for music information intake, processes and information retrieval depending on musicians’ expertise and we have stressed the importance of learning through interaction. In the process of skill acquisition, when self-confidence is gained strategies are simultaneously adjusted (Bandura, 1997; McPherson and McCormick, 2006). In reference to the current debate about the nature of music reading, we have compared musical and verbal processing during comprehensive reading of texts and scores. On the whole, considering the model of Baddeley (1990), musicians’ cognitive resources during music reading would be mobilized depending on the expertise and the music style