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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

L'utilisation de la musique comme support de nouveaux apprentissages dans le vieillisement normal et la maladie d'Alzheimer / Using music as a mnemonic in normal aging and Alzheimer’s disease

Moussard, Aline 22 May 2012 (has links)
L’objectif de ce travail de thèse est d’évaluer le potentiel de la musique comme support mnémotechnique pour l’acquisition de nouvelles informations chez des personnes âgées saines et atteintes de la maladie d’Alzheimer (MA). Les bénéfices de la musique sur la cognition ont souvent été mis en évidence, y compris chez des populations âgées ou atteintes de démence. Parallèlement, chez des sujets jeunes, l’idée que la musique peut servir de support pour la mémoire a été largement débattue. Pourtant, très peu d’études ont posé cette question auprès de populations âgées ou dans la démence, malgré le besoin persistant de stratégies d’intervention dans ce domaine. Dans le présent travail, deux études sont menées dans une cohorte de 8 participants atteints d’un stade léger de la maladie d’Alzheimer, et 7 participants âgés sains appariés en âge et niveau de scolarité. La première étude porte sur la mémoire verbale, et compare l’apprentissage et la rétention de paroles (textes inconnus) présentées de manière récitée ou chantée. Lorsque les paroles sont chantées, différents degrés de familiarité de la mélodie sont contrastés. Aussi, l’action motrice étant intimement liée à l’écoute musicale, nous contrastons deux procédures d’apprentissage impliquant (ou non) la production synchronisée des paroles à mémoriser pendant l’encodage : le participant est invité à chanter à l’unisson avec un modèle (ou à écouter simplement sans chanter). Les résultats de cette étude sont présentés et discutés dans les deux premiers articles de la partie expérimentale. Ils suggèrent globalement que la musique n’aide pas l’apprentissage en rappel immédiat ; un effet délétère est même observé lorsque la mélodie utilisée est non familière. Par contre, la musique favorise la rétention à long terme des paroles, principalement pour les participants MA. Elle ne semble cependant pas interagir avec la procédure d’apprentissage impliquant le chant à l’unisson. La seconde étude porte sur l’apprentissage de séquences de gestes. Suivant la même logique que dans la première étude, nous explorons l’influence d’un accompagnement musical (versus apprentissage en silence) et d’une procédure d’apprentissage avec production synchronisée (versus observation) des gestes durant l’encodage. Les résultats (article 3) ne montrent pas non plus d’interaction entre l’accompagnement et la procédure d’apprentissage, mais différents effets de chaque composante sur les deux groupes de participants. Effectuer les gestes en synchronie avec un modèle lors de l’encodage est bénéfique pour les sujets Contrôles, mais plutôt délétère pour les participants MA. Par contre, l’accompagnement musical favorise davantage l’apprentissage chez les sujet MA que chez les Contrôles. En discussion générale, nous discutons les implications de ces résultats pour la neuropsychologie fondamentale et clinique, et proposons notamment différentes recommandations visant à maximiser ces effets et à les rendre pertinents pour l’usage thérapeutique en stimulation cognitive. / This thesis research aims to test the potential of music as a mnemonic support for new learning in normal elderly and Alzheimer’s disease (AD) participants. Several studies have highlighted the beneficial effects of music on cognition in aging and dementia. At the same time, in young adults, the idea that music could serve as a mnemonic support is highly debated. Yet, very few studies addressed this question in aging or dementia. In the present work, we conduct two studies in a cohort of 8 mild Alzheimer’s disease and 7 matched control participants. The first study concerns verbal memory, and compares learning and different retention delays of lyrics (unknown texts) that are either spoken or sung. When lyrics are sung, different degrees of melody familiarity are contrasted. Moreover, as motor activity is strongly related to music, we compare two learning procedures that are either synchronized or not with the production of these lyrics during encoding: 1) participants sing in unison with the model or 2) participants hear the model without singing. Results of this study are presented and discussed in the first two articles of the experimental section. Globally, music does not show aid for learning measured in immediate recall; we even observed a harmful effect when lyrics are sung on a non-familiar melody. But music helps long-term retention of lyrics, particularly for AD participants. Nevertheless, music does not clearly interact with learning procedure involving unison singing. The second study of the thesis investigates the learning of gesture sequences. Similarly to the first study, we explore influence of music versus silence as background accompaniment, and synchronized production versus observation of gestures during encoding. Results (article 3) showed again no interaction between background accompaniment and learning procedure, but different effects of each variable on both groups. Learning gestures with synchronized production is beneficial for normal controls, but harmful for AD participants. On the other hand, musical accompaniment led to greater benefit for AD participants than for controls. In the general discussion, we present the implications of these results for fundamental and clinical neuropsychology. We propose some recommendations to maximize these effects and make them relevant for therapeutic care.
72

EFEITO DA ESPERMIDINA SOBRE A PERSISTÊNCIA DA MEMÓRIA EM RATOS / EFFECT OF THE SPERMIDINE IN THE MEMORY PERSISTENCE IN RATS

Signor, Cristiane 22 February 2013 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The long-term memory involves three stages: acquisition, consolidation and extinction. However was recently described a new phase of consolidation, called the persistence of memory. At this stage, crucial events occur 12 hours after the acquisition, in which the synthesis of new proteins and brain derived neurotrophic factor, are essential. The polyamines putrescine, spermidine and spermine, they act as endogenous modulators of various ion channels, including the glutamatergic receptor subtype N-methyl-D-aspartate. Systemic and intra-cerebral spermidine, immediately after training, improves memory in various tasks in rats. However, no studies demonstrating the effect of spermidine on the persistent memory. Thus, we investigated the effect of systemic administration of spermidine, and arcaine, antagonist of polyamine site on the N-methyl-D-aspartate, the persistence of memory, through the task of contextual fear conditioning. For this study, were used adult male Wistar rats, which underwent a training session on the task of contextual fear conditioning, and 12 hours after training, received a systemic administration of spermidine (0.1-30 mg/kg ), arcaine (0.1-10 mg/ kg) or the combination of spermidine and arcaine. In the second or the seventh day after training the mice were tested. Systemic administration of spermidine improved, whereas systemic administration of impaired arcaine the persistence of memory, when the rats were tested in the second and seventh day after training. The arcaine (0.1 mg / kg) in a dose that has no effect per se prevented improved starry induced by spermidine (10 mg/kg), whereas spermidine (1 mg/kg) dose not effect per se has prevented the worsening of starry arcaine induced (10 mg/kg), when the rats were tested in the second and seventh day after training. These results suggest the involvement of spermidine in persistent memory in rats. / A memória de longa duração envolve três fases: aquisição, consolidação e evocação. No entanto, recentemente foi descrita uma nova fase de consolidação, denominada de persistência da memória. Nesta fase, ocorrem eventos cruciais 12 horas após a aquisição, na qual a síntese de novas proteínas e do fator neurotrófico derivado do encéfalo, são essenciais. As poliaminas putrescina, espermidina e espermina, atuam como moduladores endógenos de diversos canais iônicos, incluindo o subtipo de receptor glutamatérgico N-metil-D-aspartato. A administração sistêmica e intra-cerebral de espermidina, imediatamente após o treino, melhora a memória em diversas tarefas em ratos. Entretanto, não há estudos demonstrando o efeito da espermidina sobre a persistência da memória. Assim, nós investigamos o efeito da administração sistêmica de espermidina, e de arcaína, antagonista do sítio das poliaminas no receptor N-metil-D-aspartato, na persistência da memória, através da tarefa de medo condicionado contextual. Para este estudo, foram utilizados ratos Wistar machos adultos, os quais, foram submetidos a uma sessão de treino na tarefa de medo condicionado contextual, e 12 horas após o treinamento, receberam uma administração sistêmica de espermidina (0,1-30 mg/kg), arcaína (0,1-10 mg/kg) ou a associação de espermidina e arcaína. No segundo ou no sétimo dia após o treino os ratos foram submetidos ao teste. A administração sistêmica de espermidina melhorou, enquanto que a administração sistêmica de arcaína prejudicou a persistência da memória, quando os ratos foram testados no segundo e no sétimo dia após o treino. A arcaína (0,1 mg/kg) na dose que não possui efeito per se, preveniu a melhora da persistência da memória induzida pela espermidina (10 mg/kg), enquanto que a espermidina (1 mg/kg) na dose que não possui efeito per se, preveniu a piora da persistência da memória induzida pela arcaína (10 mg/kg), quando os ratos foram testados no segundo e no sétimo dia após o treino. Estes resultados sugerem o envolvimento da espermidina na persistência da memória em ratos.
73

Avaliação da memória de longo prazo em idosos nas condições háptica e visual

Ferreira, Cyntia Diógenes 27 April 2015 (has links)
Submitted by Viviane Lima da Cunha (viviane@biblioteca.ufpb.br) on 2016-01-25T15:20:09Z No. of bitstreams: 1 arquivototal.pdf: 1612344 bytes, checksum: f0cfaa677e2c9ebbc56a8c6814476d5f (MD5) / Made available in DSpace on 2016-01-25T15:20:09Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 1612344 bytes, checksum: f0cfaa677e2c9ebbc56a8c6814476d5f (MD5) Previous issue date: 2015-04-27 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The ratings used for the memory studies may vary from the nature of the encoding of stimuli, as to the time when the information remains stored for later retrieval and as the form of engaged learning. Thus, studies that evaluate the coded memory through active manipulation of objects, the haptic memory, are scarce, in particular the assessment of long-term oblivion rates. In the healthy aging process subsystems memory have different significant decline in its components. Therefore, the present study aimed to evaluate the real objects oblivion rates and family processed in the haptic and visual modality in two time slots to recall memories and recognition in a sample of 104 elderly people, of both sexes, without commitment cognitive. For this, a wooden box and a turntable for the presentation of haptic and visual stimuli, respectively were used. The procedure consisted of two phases, one phase of study (stimulus presentation) and another test (recall or recognition tasks), at intervals of 1 hour or 1 day. The Mann-Whitney test for independent samples showed significant differences in the recall task only at 1 day interval, with a superior visual recall of information (U = 55.50, p = 0.029, r =-0,60). In the assessment of the accuracy of recognition revealed that only 1 day interval was no significant difference, however, by superior to haptic condition (U = 55.50, p = 0.029, r =-0,55). In summary, the results show that for different memory tasks evaluation condition influences the forgetting rates over time. So it is necessary that new designs, with the addition of more extended periods of time, may bring further clarification. / As classificações utilizadas para os estudos da memória podem variar em relação a natureza da codificação dos estímulos, quanto ao tempo em que as informações permanecem armazenadas para posterior evocação e quanto a forma de aprendizado envolvida. Dessa forma, os estudos que avaliam a memória codificada através manipulação ativa dos objetos, a memória háptica, são escassos, em especial a avaliação das taxas de esquecimento a longo prazo. No processo de envelhecimento saudável os subsistemas da memória apresentam declínio significativo diferenciado em seus componentes. Diante disso, a presente pesquisa teve por objetivo avaliar as taxas de esquecimento de objetos reais e familiares processadas na modalidade háptica e visual em dois intervalos de tempo para memórias de recordação e reconhecimento em uma amostra de 104 idosos, de ambos os sexos, sem comprometimento cognitivo. Para isso, foi utilizada uma caixa de madeira e uma plataforma giratória para a apresentação dos estímulos hápticos e visuais, respectivamente. O procedimento consistiu em duas fases, uma fase de estudo (apresentação dos estímulos) e outra de teste (tarefas de recordação ou reconhecimento), realizada após os intervalos de 1 hora ou 1 dia. Foram encontradas diferenças significativas na tarefa de recordação apenas no intervalo de 1 dia, com uma superioridade na recordação visual das informações (U=55,50, p=0,029, r=-0,60). E na avaliação da acurácia do reconhecimento revelou que apenas no intervalo de 1 dia houve diferenças significativas, no entanto, com superioridade para a condição háptica (U=55,50, p=0,029, r=-0,55). Em resumo, os resultados mostram que para as diferentes tarefas de avaliação da memória a condição influencia nas taxas de esquecimento ao longo do tempo. Assim é necessário que novos delineamentos, com o acréscimo de intervalos de tempo mais prolongados, possam trazem maiores esclarecimentos.
74

Fractais e redes neurais artificiais aplicados à previsão de retorno de ativos financeiros brasileiros / Fractals and artificial neural networks applied to return forecasting of Brazilian financial assets

João Nunes de Mendonça Neto 13 August 2014 (has links)
Este estudo tem como problema de pesquisa a previsão de retorno de ativos financeiros. Buscou verificar a existência de relação entre memória ou dependência de longo prazo em séries temporais fractais e erro de previsão de retornos de ativos financeiros obtida por meio de Redes Neurais Artificiais (RNA). Espera-se que séries temporais fractais com maior memória de longo prazo permitam obter previsões com menor nível de erro, na medida em que a correlação entre os elementos da série favoreça a qualidade de previsão de RNA. Como medida de memória de longo prazo, foi calculado o expoente de Hurst de cada série temporal, o qual sofreu uma transformação para atuar como um índice de previsibilidade. Para medir o erro de previsão, foi utilizada a Raiz do Erro Quadrado Médio (REQM) produzida pela RNA em cada série temporal. O cálculo do expoente de Hurst foi realizado por meio do algoritmo da análise Rescaled Range (R/S). A arquitetura de RNA utilizada foi a de Rede Neural com Atraso Alimentada Adiante (TLFN), tendo como processo de aprendizagem supervisionada o modelo de retropropagação com gradiente descendente para minimização do erro. A amostra foi composta por ativos financeiros brasileiros negociados na Bolsa de Valores, Mercadorias e Futuros de São Paulo (BM&FBovespa), especificamente ações de companhias abertas e fundos de investimentos imobiliários em um período de 10 anos. Os resultados mostraram que a relação entre as variáveis foi significativa para previsões de retornos médios diários de 126 e 252 dias úteis e não significativa para previsão de retorno de 1 dia útil. Quando a análise foi realizada em somente ativos financeiros com expoentes de Hurst persistentes, a relação foi significativa para previsão de 1 dia útil e ainda mais significativa para previsão de 126 e 252 dias úteis, não sendo significativa quando realizada a análise em somente os ativos financeiros antipersistentes. A amostra foi também particionada entre os ativos que participaram e os que não participaram do índice Bovespa (IBOVESPA) no terceiro quadrimestre de 2013. Quando analisados somente os ativos que participaram do IBOVESPA, não houve relação significativa entre as variáveis estudadas, havendo relação significativa somente quando analisados os ativos não participantes. A participação no IBOVESPA apresentou relação significativa com memória de longo prazo e não foi encontrada relação significativa dessa participação com o erro de previsão de RNA. Os resultados encontrados sugerem que o expoente de Hurst pode ser utilizado previamente para selecionar séries temporais de retornos de ativos financeiros que são mais viáveis de serem previstos, particularmente escolhendo aqueles ativos com retornos mais persistentes e que não participem do IBOVESPA. Um gestor que deseje imprimir uma administração mais ativa de seus investimentos poderia utilizá-lo para selecionar uma carteira de ativos com essas características e realizar previsões com qualidade superior ao utilizar RNA. Um investidor que execute uma administração passiva de investimentos deveria compô-la com ativos com expoentes de Hurst característicos de processos em passeio aleatório, a fim de que não seja prejudicado por movimentos não aleatórios do mercado contra os quais não esteja se protegendo. / This study has the research problem of forecasting financial assets return. It aimed to verify the existence of relationship between long-term memory or dependence in fractal time series and prediction error of financial assets returns obtained by Artificial Neural Networks (ANN). It is expected that fractal time series with larger memory could achieve predictions with lower error, since the correlation between the elements of the series favors the quality of ANN prediction. As a long-term memory measure, the Hurst exponent of each time series was calculated, which has undergone a transformation to act as an index of predictability. To measure the prediction error, the Root Mean Square Error (RMSE) produced by ANN in each time series was used. The Hurst exponent computation was conducted through the rescaled range analysis (R/S) algorithm. The ANN architecture was Time Lagged Feedforward Neural Network (TLFN), with backpropagation supervised learning process and gradient descent for error minimization. The sample was composed of Brazilian financial assets traded in the Securities, Commodities & Futures Exchange of Sao Paulo (BM&FBovespa), more specifically public companies shares and real estate investment funds. The results showed that the relationship between the variables was significant for forecasting daily average returns of 126 and 252 business days, and not significant for predicting returns of 1 business day. When the analysis was performed only in financial assets with persistent Hurst exponents, the relationship was significant for predicting returns of 1 business day and even more significant for prediction returns of 126 and 252 business days. The relationship was not significant when the analysis was performed in only antipersistent financial assets. The sample was also partitioned among the assets participating and not participating in the Bovespa Index (IBOVESPA) of the third quarter of 2013. When only assets that participated in the IBOVESPA are considered, there was no significant relationship between the variables studied, existing significant correlation only when no participants are considered. Participation in IBOVESPA showed a significant relationship with long-term memory and no significant relationship of such participation with ANN prediction error was found. The results suggest that the Hurst exponent can be used to previously select time series of financial assets returns that are most feasible to predict, particularly choosing those assets with more persistent returns and not participating in the IBOVESPA. A manager who wishes to make a more active investment management could use it to select a portfolio with these characteristics and make predictions with superior quality when using artificial neural networks. An investor who accomplishes a passive investment management should compound his portfolio with assets that follows Hurst exponents characteristic of random walk processes, so that his is not impaired by no random market movement that he is not protected.
75

Manipulation in Newspaper Articles : A Political Discourse Analysis of Lexical Choice and Manipulation in Japanese Newspaper Crisis Reporting in the case of North Korea

Zouave, Sonia January 2014 (has links)
This paper analyzes some forms of linguistic manipulation in Japanese in newspapers when reporting on North Korea and its nuclear tests. The focus lies on lexical ambiguity in headlines and journalist’s voices in the body of the articles, that results in manipulation of the minds of the readers. The study is based on a corpus of nine articles from two of Japan’s largest newspapers Yomiuri Online and Asahi Shimbun Digital. The linguistic phenomenon that contribute to create manipulation are divided into Short Term Memory impact or Long Term Memory impact and examples will be discussed under each of the categories.The main results of the study are that headlines in Japanese newspapers do not make use of an ambiguous, double grounded structure. However, the articles are filled with explicit and implied attitudes as well as attributed material from people of a high social status, which suggests that manipulation of the long term memory is a tool used in Japanese media. / この論文は日本語の新聞中の北朝鮮と核実験に関する報告記事の曖昧さと操作的な態度についてである。この研究は特に北朝鮮について新聞の記事中の計画的で無意識に言語的な操作態度についてである。記事の見出しと読者の心意を関わる曖昧さについてである。全部の記事は読売新聞と朝日新聞に取ったが、全部の中に、多大態度がある。調査は日本の最大の新聞読売オンラインと朝日新聞デジタルの九の記事のコーパスに基づいてである。研究の主な結果は、日本の新聞の見出しがあいまいな構造を利用していないことだが、記事は明示的な態度だけでなく、多大な引用文で満たされている
76

Zapamatovatelnost a nápadnost změn - vztah paměti a vnímání / Scene memorability and change salience: memory-perception relationship

Ptáčková, Barbora January 2017 (has links)
In the thesis, I focus on the relationship between visual memory and the ability to detect changes in photographs. In the theoretical part I introduce the change detection and "change blindness" phenomenon. Next, this work explores visual memory and refers to studies that focused on visual long-term memory and its role in change detection. The objective of the empirical part of this thesis is to map the relation between visual memory (scene memorability) and change detection illustrated on the ability to recognize changes in photographs of indoor and outdoor scenes. Research was conducted by means of an experiment devised in PsychoPy using flicker paradigm. The research sample comprised 42 respondents, mainly university students. Research results did not confirm the existence of a relation between visual memory and change detection. No correspondence was found between these variables, not even at the level of each category, suggesting that change detection depends on other factors than visual long-term memory. KEYWORDS: Change blindness, visual long-term memory, change detection, memorability, perception, experiment
77

Cross-cultural normative indicators on the Wechsler Memory Scale (WMS) associate learning and visual reproduction subtests

Fike, Lauren January 2008 (has links)
A comprehensive battery of commonly used neuropsychological tests, including the WMS Associate Learning and Visual Reproduction subtests, forming the focus of this study, were administered to a southern African sample (n = 33, age range 18-40). This sample composed of black South African, IsiXhosa speakers with an educational level of Grade 11 and 12, derived through DET and former DET schooling. The gender demographics were as follows; females n = 21 and males n = 12. This sample was purposefully selected based on current cross-cultural research which suggests that individuals matching these above-mentioned demographics are significantly disadvantaged when compared to available neuropsychological norms. This is due to the fact that current norms have been created in contexts with socio-cultural influences; including culture, language and quantity and quality of education distinctly dissimilar to individuals like that composed in the sample. Hence the purpose of this study was fourfold namely; 1) Describe and consider socio-cultural factors and the influence on test performance 2) Provide descriptive and preliminary normative data on this neuropsychologically underrepresented population 3) Compare test performance between age and gender through stratification of the sample and finally to 4) Evaluate the current norms of the two WMS subtests and assess their validity for black South Africans with DET and former DET schooling with comparisons to the results found in the study. Information derived from the statistical analyses indicated that a higher performance in favour of the younger group over the older age range was consistently found for both WMS subtests. With regards to gender, some higher means were evident for the male population in the sample than was produced by the female group. Lastly, due to the fact that most scores derived from the sample were considerably lower when compared to the available norms, it is felt that socio-cultural factors prevalent to this population are a significant cause of lower test performance and thus warrant the development of appropriate normative indicators.
78

Effets promnésiants de l'activation des récepteurs sérotoninergiques de type 4 (5-HT4) dans des modèles rongeurs (rats, souris) de vieillissement normal et pathologiques

Jacquet, Marlyse 02 December 2014 (has links)
Chez les rongeurs, la mémoire procédurale est préservée alors que la mémoire « déclarative » est profondément altérée au cours du vieillissement normal ou pathologique.L’injection d’un agoniste partiel des récepteurs 5-HT4 (SL 65.0155. 0.01mg/kg) permet aux rongeurs de récupérer leurs facultés dans une tâche de discrimination olfactive, le labyrinthe olfactif par exemple.L’activation des récepteurs 5-HT4 par un agoniste pourrait être utilisée pour lutter contre les dysfonctionnements mnésiques rencontrés dans certaines pathologies neurodégénératives telle que la maladie d’Alzheimer. L’injection d’un agoniste partiel des récepteurs 5-HT4 (SL 65.0155. 0.01mg/kg) permet aux rongeurs de récupérer leurs facultés dans une tâche de discrimination olfactive, le labyrinthe olfactif par exemple.L’activation des récepteurs 5-HT4 par un agoniste pourrait être utilisée pour lutter contre les dysfonctionnements nésiques rencontrés dans certaines pathologies neurodégénératives telle que la maladie d’Alzheimer. / In normal aging or pathological brain diseases in rodents procedural memory is spared while reference memory is deeply impaired.Injection of a partial selective 5-HT4 agonist (SL65.0155. 0.01mg/kg) enabled complete recovery of association learning performance in an olfactory associative discrimination task, the olfactory tubing maze for exemple.Activation of 5-HT4 receptors by a selective agonist could be useful for the symptomatic treatment of memory dysfunctions related to pathological aging such as Alzheimer’disease.
79

Found Things: Variations in information density in long-form narrative

Bohannon, Catherine Ridder January 2022 (has links)
This dissertation makes the case that treating digitized corpora of literary works as cognitive artifacts can provide particular insight into how the reading mind apprehends events within an imagined world and, thereby, provide potentially useful functional models for event perception, emotional memory, and determining what’s “real.” Most essentially, it will make the case that the deepest feature of narrative cognition may involve an “information distribution” assessment, wherein the variation of information density over time cues the mind to attend to denser events with increased attention, potentially saving more of their content for long-term memory. This mimics what cognitive research has frequently established for real-world processing of emotionally stimulating events, wherein emotional memory tends to be better retained over time, with more detail, fewer conflations, and more resistance to fading, while neutral events tend to be relegated to gist or forgotten. Put together, this produces an ordering of autobiographical memory that resembles a glimmering string of pearls: densely detailed memories strung together over time, separated by thinner, looser memories and gist, with a particular cluster of these “pearls” towards the middle for the memory bump of the mid-teens to mid-twenties. While many have argued for larger schemas or socially influenced self-regard as the major driver for memory emphasis in one’s Life Story, if autobiographical memory is anything like a novel, it may prove a bit simpler: most of the bigger pearls mark where one’s sensory array “dilated” in moments of arousal, and their lustrous, persistent “shine” may be a matter of how likely it was that one returned to those memories over time. Chapter 1 examines what we do and don’t know about the reading mind, settling on a narrower definition of immersive narrative reading as an exceptional cognitive state which moves in and out of what cognitive psychologists call “flow” and a more passive, vivid “daydream.” This is an inherently unstable activity that requires a great deal of assistance from the text, thereby providing useful targets of analysis for researchers interested in perception, emotion, and memory, with a particular eye towards embodied cognition. It then discusses key gaps in the scientific literature and literary scholarship around event perception and narrative cognition, some of which this project aims to partially fill through quantitative analysis of literary texts. This chapter will also discuss the promise and perils of treating literary corpora like the novels in Project Gutenberg as cognitive artifacts: the known limitations of using “canon” texts as a representative sample of literature in general, the rarity of reading, and what it means to “backsolve” cognition through its artifacts. Chapter 2 describes a series of experiments conducted on a corpus of a few thousand novels and nonfiction narratives contained in Project Gutenberg and the Nickels and Dimes Project. Leaning on the “string of pearls” metaphor for autobiographical memory organization, this chapter will promote a model of long-form narrative’s fundamental mnemonics as something that mimics that organizational pattern: information density that varies over time, predicting not only the pace of in-narrative time passing, but which “moments” or features of the narrative will be important for the reader to remember over multiple reading events, while others will be forgotten or relegated to gist. This pattern closely mimics models of autobiographical memory in cognitive psychology, not only of so-called “flashbulb memory” or surprising, high-affect events, but also of Life Story in general: vast periods of fleeting detail, with dense memory clusters around events that were encoded in moments of arousal, with curious memory affects just before and after those events, possibility illustrating what Jefferey Zacks presents as a “gating” model of event perception. Drawing on the scientific literature on event segmentation, arousal and memory, and time perception, and likewise drawing on literary scholarship on time and stylistics in the novel, this chapter will explore the implications and limitations of using POS tagging to try and tease out quantifiable units of “information” from large corpora of novels utilizing one-way repeated measures MANOVA. Applications for these findings in literary scholarship will be discussed throughout—for instance, while scenes involving sex or violence are predictably information-dense in most texts in the corpus that were hand-scored for accuracy (and subsequently used as training texts for the algorithm), in-book variation from the norm and from nearby passages is more predictive than a raw density score alone. For example, when Stephen Dedalus has sex in Portrait of the Artist as a Young Man, imagistic detail goes down compared to nearby scenes and compared to the more detail-dense passages in the text, which seems to be typical of Joyce: while he does vary density according to temporality and that maps roughly to “significant” scenes, the most emotional scenes tend to be written more sparely (spare for that author, that is—Joyce is not Hemingway). That may be an authorial quirk, or it may be that he relies upon a second strategy to stimulate a reader’s emotional response: semantic content that’s normally cued to a strong negative or positive valence. Chapter 3 will attend to the ways some authors resist narrative’s “ease of use” in order to prompt their readers to interrogate what’s Real. This chapter zooms in on a specific period of American and British literature, and a genre within that brief time: the rise of Creative Nonfiction and/or New Journalism, with a close read or “case study” of George Orwell’s Homage to Catalonia and James Agee’s Let Us Now Praise Famous Men. This chapter proposes that the authors set out to create narratives that would reflect the “real” lives of their subjects, with an objective of making those lives feel real to their readership. But were they successful? Drawing on cognitive psychology research in psychosis, metacognition, and temporal sense, this chapter aims to elucidate how literary narratives like these may “aim to fail” at certain features of deep narrative form (as discussed in the prior chapters) in order to “startle” their readers into a less passive state, in order to better mimic the qualia of witnessing something in the real world, and thereby produce a sense that the subjects within the text are Real. These embedded structural failures are often more subtle than anything Brechtian, but nevertheless can be found both quantitatively and in close reading, which may indicate that when a long-form narrative text purposefully aims to make a reader uncomfortably aware of Reality--especially when motivated by known, deep ethical concerns--it may “work” in ways that have less to do with the subject or content of the text and more to do with form.
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Role of Context in Episodic Memory : A Bayesian-Hebbian Neural Network Model of Episodic Recall

Raj, Rohan January 2022 (has links)
Episodic memory forms a fundamental aspect of human memory that accounts for the storage of events as well as the spatio-temporal relations between events during a lifetime. These spatio-temporal relations in which episodes are embedded can be understood as their contexts. Contexts play a crucial role in episodic memory retrieval. Despite this, little work has been done in the computational neuroscience literature on trying to investigate this relationship further. These interactions can be modelled with attractor neural networks such as the Bayesian Confidence Propagation Neural Network (BCPNN). In this project, the interaction between contextual aspects and memory items are studied by developing an abstract computational model of episodic memory retrieval. The effect of increasing the number of items associated with a particular context on the overall recall performance is examined. Finally, the role of synaptic plasticity modulation of certain item-context associations on recall is also analysed. It is found that an inverse relationship exists between the number of items associated with a context and their subsequent recall rates, i.e. as the number of items associated with an episodic context increase, the recall rates of the corresponding items decrease. Furthermore, it is found that the item-context pairs for which the synaptic plasticity is modulated during learning, have a significantly higher recall rate than the remaining unmodulated associations. / Episodiskt minne utgör en grundläggande aspekt av det mänskliga minnet som står för lagring av händelser samt de spatio-temporala relationerna mellan dem under en livstid. De spatio-temporala relationer i vilka episoderna är inbäddade kan betraktas som deras kontexter, vilka spelar en avgörande roll i episodisk minnesåterkallande. Trots detta har inte mycket forskning inom beräkningsneurovetenskapi gjorts för att närmare undersöka bakomliggande neurala mekanismer. Minnesåterkallandet inklusive interaktioner mellan kontext och minnesobjekt kan modelleras med återkopplade neurala nätverk, s k attraktornät, t ex av typen för Bayesian Confidence Propagation Neural Network (BCPNN). I det här projektet studeras interaktionen mellan kontextuella aspekter och minnesobjekt genom att utveckla en abstrakt BCPNN-modell av episodisk återkallande. Effekten av att variera antalet objekt-kontextassociationer på återkallningsbeteende undersöks. Slutligen analyseras också effekten av synaptisk plasticitetsmodulering av vissa minnesobjekt-kontext-associationer på korrekt minnesåterkallelse. Det observeras att när antalet objekt associerade med ett sammanhang ökar, minskar återkallningsfrekvensen för motsvarande objekt. Vidare är det konstaterat att minnesobjektföremålet-kontextpar för vilka den synaptiska plasticiteten moduleras under lärande, har en betydligt högre återkallningsgrad än de återstående omodulerade föreningarna.

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