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Neonatal Methamphetamine Administration Induces Region-Specific Long-Term Neuronal Morphological Changes in the Rat Hippocampus, Nucleus Accumbens and Parietal CortexWilliams, Michael T., Brown, Russell W., Vorhees, Charles V. 01 June 2004 (has links)
Previous studies have demonstrated that rats exposed to methamphetamine (MA) during the neonatal period display deficits in spatial learning and memory. The underlying correlates are; therefore, this study was devised to determine whether neuronal changes occur in the dentate gyrus (DG), nucleus accumbens (NAcc) and cortex of adult rats exposed to 10 mg/kg MA administered four times daily from P11-20 using Golgi-Cox staining [Gibb, R. & Kolb, B. (1998) J. Neurosci. Meth., 79, 1-4]. The DG and NAcc demonstrated a decrease in the number of spines per neuron and the NAcc showed an associated decrease in dendritic length. Selective changes in cortex were observed because increased dendritic length in the parietal cortex occurred with no change in the number of spines, and no differences were noted for either dendritic length or spines in the medial frontal cortex. The data suggest a potential cause for the learning and memory deficits induced by neonatal MA exposure; however, the underlying mechanism that produces these neuronal changes is.
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Mind wandering regulation by non-invasive brain stimulation / 非侵襲脳刺激法によるマインドワンダリング制御Kajimura, Shogo 23 March 2017 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(教育学) / 甲第20127号 / 教博第204号 / 新制||教||167(附属図書館) / 京都大学大学院教育学研究科教育科学専攻 / (主査)准教授 野村 理朗, 教授 齊藤 智, 教授 Emmanuel MANALO / 学位規則第4条第1項該当 / Doctor of Philosophy (Education) / Kyoto University / DGAM
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How We Know When We Don't Know Enough: Neural Representations of Probabilistic Inference and Information DemandSingletary, Nicholas Martin January 2023 (has links)
In real-world settings, decision-making typically resembles a stepwise process in which one decides which information to sample before deciding to which decision option to commit. The former step is called instrumental information-seeking, and theoretical and empirical findings indicate that it is mediated by the value of information (VOI), the extent to which obtaining information increases the expected value of future actions and decisions. Economic theory predicts that to estimate VOI, decision-makers conduct a preposterior analysis in which they prospect what they would expect to know about the decision options after observing the information—or, in terms of Bayesian inference, they should prospect the future posterior probabilities. But the neural mechanisms underlying this early step of the computation of VOI remain an open question.
Therefore, to further investigate the neural substrates of instrumental information-seeking, we used functional magnetic resonance imaging (fMRI) in conjunction with two interrelated behavioral tasks in humans. With one task, we examined the demand for instrumental information, but since preposterior analysis relies on the prospection of potential future posterior beliefs, we included another task to examine how people form posterior beliefs after receiving information. We found that regions of posterior parietal cortex and occipital fusiform gyrus appear to support a preposterior analysis through the prospection of expected posterior certainty. This aligned with our finding of a region of parieto-occipital cortex that appears to support Bayesian inference by integrating the prior probability of a hypothesis with the likelihood of observed information. These results imply that parietal cortex plays a key role in Bayesian inference, supporting preposterior analysis during information-seeking in addition to Bayesian inference during categorical decision-making.
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Parietal cell regeneration in rat gastric mucosal wounds : a quantitative light and electron microscopical studyBlom, Håkan January 1982 (has links)
The aims of the study were to obtain a method with which it would be possible to produce standardized wounds in the gastric mucosa, and to follow the regeneration of the acid producing parietal cells in those lesions during different experimental conditions. Quantitative methods applied to light and electron microscopy were used. Wounds were cauterized in the corpus mucosa in Sprague-Dawley rats and in addition, pyloroplasty, truncal vagotomy with pyloroplasty or ant- rectoiriy were performed. Other groups of rats with wounds were given long-term treatment with pentagastrin or cimetidine. Stimulation tests were carried out in two groups of wound operated rats. After different periods of time the animals were perfusion fixed and specimens from the wounds and normal mucosa beside the wounds were prepared for light and electron microscopy. By means of stereological techniques, different mucosal and cellular structures were then measured. Parietal cells were found in 90 days old wounds. At this stage they were immature with large nuclei and few specialized cell organelles. In spite of this appearance they were able to respond morphologically to stimulation and to secrete acid. With further healing the morphology of the parietal cells became normal, but their volume fraction in the mucosa remained subnormal. The fraction of mucosa occupied by epithelial cells also stayed lower than normal. Pyloroplasty resulted in decreased cell and nuclear size of both normal and regenerating parietal cells. In the latter, there was also a decrease in the mitochondrial volume density. If a truncal vagotomy was added to the pyloroplasty these changes disappeared and, in addition, an increase in parietal cell volume density was noticed in the normal mucosa. Antrectorny produced smaller parietal cells, and their maturation was delayed. Furthermore, mucosal thickness decreased. If pentagastrin was given to rats with wounds an increase in the number of parietal cells was noted, but maturation and morphology remained unaffected. Cimetidine treatment did not affect the parietal cell volume density in wounds or normal mucosa. However, a large increase in the secretory surface density was noticed when the effect of the last dose had ceased. / <p>S. 1-45: sammanfattning, s. 47-121 utgörs av 5 uppsatser</p> / digitalisering@umu
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Associative recognition : exploring the contributions of recollection and familiarityMurray, Jamie G. January 2014 (has links)
Episodic memory refers to the storage and retrieval of information about events in our past. According to dual process models, episodic memory is supported by familiarity which refers to the rapid and automatic sense of oldness about a previously encoded stimulus, and recollection which refers to the retrieval of contextual information, such as spatial, temporal or other contextual details that bring a specific item to mind. To be clear, familiarity is traditionally assumed to support recognition of item information, whereas recollection supports the recognition of associative information. Event Related Potential (ERP) studies provide support for dual process models, by demonstrating qualitatively distinct patterns of neural activity associated with familiarity (Mid-Frontal old/new effect) and recollection (Left-Parietal old/new effect). In the current thesis, ERPs were used to address two important questions regarding associative recognition – namely, the function of the neural signal supporting recollection and whether familiarity can contribute to the retrieval of novel associative information. The first series of experiments was aimed at addressing how recollection operates by employing a recently developed continuous source task designed to directly measure the accuracy of retrieval success. To date, the function of recollection has been fiercely debated, with some arguing that recollection reflects the operation of a continuous retrieval process, whereby test cues always elicit some information from memory. Alternatively, recollection may reflect the operation of a thresholded process that allows for retrieval failure, whereby test cues sometimes elicit no information from memory at all. In the current thesis, the Left Parietal effect was found to be sensitive to the precision of memory responses when recollection succeeded, but was entirely absent when recollection failed. The result clarifies the nature of the neural mechanism underlying successful retrieval whilst also providing novel evidence in support of threshold models of recollection. The second series of experiments addressed whether familiarity could contribute to the retrieval of novel associative information. Recent associative recognition studies have suggested that unitization (whereby multi-component stimuli are encoded as a single item rather than as a set of associated parts) can improve episodic memory by increasing the availability of familiarity during retrieval. To date, however, ERP studies have failed to provide any evidence of unitization for novel associations, whereas behavioural support for unitization is heavily reliant on model specific measures such as ROC analysis. Over three separate associative recognition studies employing unrelated word pairs, the magnitude of the Mid-Frontal old/new effect was found to be modulated by encoding instructions designed to manipulate the level of unitization. Importantly, the results also suggest that different encoding strategies designed to manipulate the level of unitization may be more successful than others. Finally, the results also revealed that differences in behavioural performance and modulation of the Mid-Frontal old/new effect between unitized and non-unitized instructions is greater for unrelated compared to related word pairs. In essence, the results suggest that unitization is better suited to learning completely novel associations as opposed to word pairs sharing a pre-existing conceptual relationship. Overall, the data presented in this thesis supports dual process accounts of episodic memory, suggesting that at a neural level of analysis, recollection is both thresholded and variable, whilst also supporting the assumption that familiarity can contribute to successful retrieval of novel associative information. The results have important implications for our current understanding of cognitive decline and the development of behavioural interventions aimed at alleviating associative deficits.
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Beeinflussung der deklarativen Gedächtnisleistung mittels bilateraler transkranieller Gleichstromstimulation (tDCS) über dem parietalen sowie temporalen Kortex / Effects on declarative memory via bilateral transcranial direct current stimulation (tDCS) over parietal and temporal corticesRaithel, Almuth Marianne 15 August 2016 (has links)
Die transkranielle Gleichstromstimulation (tDCS) erwies sich in der bisherigen Grundlagenforschung als bewährte Methode zur Aufschlüsselung von komplexen kognitiven Funktionen. Bisher deuten bildgebende Verfahren auf ein Zusammenwirken parietaler und temporaler Kortizes beim Rekognitionsprozess deklarativer Gedächtnisinhalte hin. In der vorliegenden Arbeit sollten nun die Auswirkungen einer bilateral temporal und parietal applizierten tDCS auf die deklarative Gedächtnisleistung während der Rekognition untersucht werden. Unter Verwendung eines einfach-blinden, kontrollierten und randomisierten Studiendesigns wurden junge, gesunde Probanden drei voneinander unabhängigen, hinsichtlich der individuellen Gedächtniskapazität ausgeglichenen Studiengruppen für Placebo-, parietale und temporale Stimulation zugeordnet. Während der Bearbeitung eines computergestützten Alt-Neu-Rekognitions-Paradigmas erhielten zwei Gruppen bilaterale tDCS mit linkshemisphärischer a-tDCS über dem parietalen bzw. temporalen Kortex und eine Gruppe Placebo-Stimulation. Zielsetzend wurde die Einflussnahme der tDCS auf die deklarative Rekognitionsleistung bezüglich verbaler Gedächtnisinformationen gemessen. Eine Verbesserung der deklarativen Rekognitionsleistung äußerte sich in höheren Trennschärfeindex- und Treffgenauigkeitswerten der beiden verumstimulierten Gruppen im Vergleich zur Placebo-stimulierten Gruppe. Ein konträres Dissoziationsmuster zeigte sich insofern, als die temporale Stimulationsgruppe eine signifikant höhere Treffgenauigkeit bei der Rekognition alter Items im Vergleich zu neuen aufwies und die parietale Stimulationsgruppe mit einer signifikant höheren Treffgenauigkeit neue Items im Vergleich zu alten wiedererkannte. Diese Ergebnisse unterstreichen die Involvierung der temporalen und parietalen Hirnareale in möglicherweise unterschiedliche Stadien des Rekognitionsprozesses deklarativer Gedächtnisinhalte.
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"What" and "Where" in the intraparietal sulcus : an fMRI study of object identity and location in visual short-term memoryHarrison, Amabilis Helen January 2008 (has links)
Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal.
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Contrôle du regard : mécanismes et substrats neuronaux de l’adaptation des mouvements oculaires saccadiques chez l’homme / Control of gaze : mechanisms and neural substrates of saccadic adaptation in HumanPanouillères, Muriel 12 July 2011 (has links)
« - Comment apprécions-nous la complexité du monde qui nous entoure ?- En bougeant nos yeux !- Pourquoi ?- Parce qu’une perception visuelle efficace (avec une acuité maximale !) nécessite de placer l’image des éléments pertinents du champ visuel au niveau d’une petite partie de notre rétine : la fovéa. » Les saccades oculaires sont les mouvements les plus rapides que peut produire notre organisme et sont malgré tout très précises. Le contrôle de ces mouvements représente un défi pour notre cerveau. En effet, ces saccades sont tellement rapides qu’aucune information visuelle ne peut modifier leur trajectoire en cours d’exécution. Mais alors, de quels moyens dispose notre cerveau pour maintenir ces performances tout au long de notre vie? En cas d’imprécision répétée, des mécanismes vont progressivement modifier l’amplitude de nos saccades oculaires afin d’en rétablir la précision. Cette adaptation saccadique repose sur des modifications centrales plastiques. Ce travail de thèse a comme vocation d’élucider les caractéristiques de l’adaptation saccadique chez l’homme. Des approches complémentaires ont permis d’étudier d’une part, l’adaptation des deux grandes catégories de saccades, réactives et volontaires, et d’autre part, l’adaptation en diminution et en augmentation d’amplitude. Nos données permettent de disséquer les mécanismes d’adaptation saccadique dans leur complexité et de mettre en évidence des structures neuronales indispensables à leur mise en place. Notre travail constitue également le support pour le développement de nouvelles procédures de rééducation, basées sur la plasticité oculomotrice. / “- How can we appreciate the complexity of the surrounding word? - By moving our eyes! - Why? - Because an efficient visual perception (with a maximal acuity!) necessitates placing the image of pertinent element from the visual scene at the level of a small part of our retina: the fovea.” Ocular saccades are the fastest movements our organism can produce and they are also highly precise. The control of these movements is a challenge for our brain. Indeed, these saccades are so fast that no visual information can be used during their execution to modify their trajectory. But then, what means does our brain have to maintain these performances all life long? In case of repeated inaccuracies, some mechanisms will progressively modify the amplitude of our ocular saccades in order to restore accuracy. This saccadic adaptation relies on central plastic modifications. The work of this doctorate has the vocation to elucidate the characteristics of saccadic adaptation in Human. Complimentary approaches allowed to study on one side, the adaptation of the two main saccade categories, reactive saccades and voluntary saccades, and on another side, the adaptation decreasing and increasing saccade amplitude. Our data dissects the complexity of mechanisms underlying saccadic adaptation and highlights the neural substrates necessary for these adaptive changes to take place. Our work constitutes also the basis for the development of new rehabilitation procedures, usingoculomotor plasticity.
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Étude per-opératoire par stimulation électrique directe des représentation sensorimotrices corticales et cérébelleuses chez l'homme / Per-operative investigation with direct electrical stimulation of cortical and cerebellar sensorimotor representations in humansMottolese, Carmine 21 December 2013 (has links)
Durant les dernières décennies, le système moteur a été largement étudié. Pourtant, bien des zones d'incertitudes persistent concernant d'une part la nature des circuits neuronaux de haut niveau impliqués dans l'émergence des sentiments d'intention ou de conscience motrice et d'autre part l'organisation des structures cérébrales de bas-niveau impliquées dans l'expression de ces sentiments. Il a été suggéré que le cortex pariétal et l'aire motrice supplémentaire pourraient jouer un rôle dans la génération des intentions motrices, alors que le cortex prémoteur pourrait plutôt sous-tendre la conscience du geste. Cela étant, les processus exacts implémentés dans chacune de ces régions, la façon dont elles interagissent fonctionnellement et la nature des signaux qu'elles échangent avec les structures sensorimotrices considérées de bas-niveau demeurent méconnus. Il est établi que ces structures bas-niveau, dont le cortex moteur primaire et le cervelet, contiennent des cartes sensorimotrices organisées de manière topographique. Cependant, l'organisation fine de cette topographie et la nature des interactions entre les différentes cartes restent à définir. Dans ce travail de thèse, j'ai utilisé la stimulation électrique directe chez des patients opérés de tumeurs et malformations cérébrales pour explorer la manière dont les multiples représentations motrices sont organisées et pour identifier les régions responsables de l'émergence des sentiments d'intention et de conscience motrice. J'ai alors pu montrer, en particulier, l'existence de cartes motrices multiples au sein des cortex moteur primaire et cérébelleux. Par ailleurs, j'ai pu identifier le rôle critique du cortex pariétal pour l'émergence du sentiment d'intention motrice et -sur la base de processus prédictifs- de la conscience d'agir. Par rapport à ce point, j'ai aussi pu mettre en évidence que le cortex prémoteur était impliqué, à travers un contrôle continu des prédictions pariétales, dans l'émergence d'une conscience d'agir non plus inférée mais véritable / During the last five decades, the motor system has been widely studied. Yet, little is known about the neural substrate of high-level aspects of movement such as intention and awareness and how these functions are related to low-level movement execution processes. It has been suggested that the parietal cortex and supplementary motor area are involved in generating motor intentions, while premotor cortex may play a role in the emergence of motor awareness. However, the precise mechanisms implemented within each of these areas, the way they interact functionally and the nature of the signals conveyed to primary sensory and motor regions is far from being understood. Furthermore, intention and awareness of movement are also influenced by peripheral information coming from the skin, muscles and joints, and this information must be integrated to produce smooth, accurate and coordinated motor actions. Cortical and subcortical structures such as the primary motor cortex and the cerebellum are known to contain motor maps thought to contribute to motor control, learning and plasticity, but the intrinsic organization of these maps and the nature of their reciprocal relations are still unknown. In this thesis I used Direct Electrical Stimulation in patients undergoing brain surgeries to investigate how multiple motor representations are organized and identify the regions responsible for the emergence of conscious motor intention and awareness. I showed, in particular, the existence of multiple efferent maps within the cerebellum and the precentral gyrus. Furthermore, I identified the critical role of the parietal cortex for the emergence of conscious intention and -based on predictive processes- motor awareness. I also provided evidence that the premotor cortex is involved in "checking" parietal estimations, thus leading to a sense of "veridical awareness"
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Os quadros parietais nas escolas do Sudeste brasileiro (1890-1970)Faria, Joana Borges de 31 July 2017 (has links)
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Previous issue date: 2017-07-31 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The wall chart is type of didactic material used to transmit school knowledge. It is the graphic representation on a flat surface of a determined subject matter. They are called wall charts because they are hung on the wall or within other apparatuses so that they can be viewed by all students simultaneously. Upon taking into consideration that these wall charts were widely utilized in schools across Brazil and in other occidental countries from the second half of the 19th Century until the middle of the 20th century, this research seeks to discover the history of this kind of didactic material in Brazil, focusing on how they were circulated, the individuals and companies involved in their production and distribution, their materiality, and their pedagogical functions, taking into consideration the school subjects of reference, the subject matter broached, and the visual language employed. For this purpose, the research used as source material the wall charts found in the following archives: CRE Mario Covas - Acervo da E.E. Caetano de Campos; Memorial do Colégio São Luís; Colégio Marista Glória e Centro de Memória da Educação Brasileira do Instituto Superior de Educação do Rio de Janeiro. Additional sources included the catalogues of companies that sold wall charts, mainly the French company Maison Deyrolle; manuals explaining the use of wall charts; work done by students of the Intituto de Educação do Rio de Janeiro from the 1950s and 1960s; photographs of classrooms, natural history, physics and chemistry classrooms, educational museums in schools, libraries, and dental clinics from schools in São Paulo; official documents like legislation and teaching programs for the primary and secondary schools of São Paulo and Rio de Janeiro, inventory logs as well as annual reports from directors and school inspectors; guides and visitors logs to universal expositions that occured in the second half of the 19th century; educational periodicals like Revista Pedagógica, Revista de Ensino, Revista Escolar, and Revista do Ensino do Rio Grande do Sul; and online databases related to scientific and educational heritage. The wall chart is an artefact and a visual image at the same time. For this reason, the study considers its principle theoretical references to be studies in material culture, in the material culture of schools, and in visual culture / O quadro parietal é um material didático usado para a transmissão de conhecimentos escolares. É uma representação gráfica de determinados conteúdos numa superfície plana. São chamados de parietais, pois são pendurados nas paredes ou em outros dispositivos para serem observados por todos os alunos simultaneamente. Ao levar em consideração que os parietais foram amplamente utilizados nas escolas brasileiras e dos países ocidentais em geral a partir da metade do século XIX até meados do século XX, esta pesquisa tem como objetivo conhecer a história deste material didático no Brasil, enfocando como se deu a sua circulação, os sujeitos e empresas envolvidos em sua produção e distribuição, a sua materialidade, suas funções pedagógicas levando em consideração as disciplinas escolares de referência, os conteúdos abordados e as linguagens visuais empregadas. Para tanto, a pesquisa utilizou como fontes os próprios quadros parietais localizados em quatro acervos escolares: CRE Mario Covas - Acervo da E.E. Caetano de Campos, Memorial do Colégio São Luís, Colégio Marista Glória e Centro de Memória da Educação Brasileira do Instituto Superior de Educação do Rio de Janeiro; catálogos de empresas que vendiam quadros parietais, principalmente da francesa Maison Deyrolle; manuais explicativos dos usos dos parietais; trabalhos de alunos do Instituto de Educação do Rio de Janeiro das décadas de 1950 e 1960; fotografias de salas de aula, gabinetes ou salas de história natural, física e química, Museu Pedagógico, Biblioteca e gabinetes dentários de escolas paulistas; documentos oficiais, como legislação e programas de ensino das escolas primárias e secundárias paulistas e cariocas, livros de inventário e relatório anuais de diretores e de inspetores de ensino; guias e relatórios de visitas às exposições universais que ocorreram na segunda metade do século XIX; periódicos educacionais, como: Revista Pedagógica, Revista do Ensino, Revista Escolar, e Revista do Ensino do Rio Grande do Sul; e banco de dados online relacionados à patrimônio científico e educativo. O quadro parietal é ao mesmo tempo um artefato e uma imagem visual, por isso, o estudo tem como principais referenciais teóricos os estudos da cultura material, cultura material escolar e da cultura visual
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