936 resultados para working memory capacity


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Background: Many school-based interventions are being delivered in the absence of evidence of effectiveness (Snowling & Hulme, 2011, Br. J. Educ. Psychol., 81, 1).Aim: This study sought to address this oversight by evaluating the effectiveness of the commonly used the Lexia Reading Core5 intervention, with 4- to 6-year-old pupils in Northern Ireland.Sample: A total of 126 primary school pupils in year 1 and year 2 were screened on the Phonological Assessment Battery 2nd Edition (PhAB-2). Children were recruited from the equivalent year groups to Reception and Year 1 in England and Wales, and Pre-kindergarten and Kindergarten in North America.
Methods: A total of 98 below-average pupils were randomized (T0) to either an 8-week block (inline image = 647.51 min, SD = 158.21) of daily access to Lexia Reading Core5 (n = 49) or a waiting-list control group (n = 49). Assessment of phonological skills was completed at post-intervention (T1) and at 2-month follow-up (T2) for the intervention group only.
Results: Analysis of covariance which controlled for baseline scores found that the Lexia Reading Core5 intervention group made significantly greater gains in blending, F(1, 95) = 6.50, p = .012, partial η2 = .064 (small effect size) and non-word reading, F(1, 95) = 7.20, p = .009, partial η2 = .070 (small effect size). Analysis of the 2-month follow-up of the intervention group found that all group treatment gains were maintained. However, improvements were not uniform among the intervention group with 35% failing to make progress despite access to support. Post-hoc analysis revealed that higher T0 phonological working memory scores predicted improvements made in phonological skills.
Conclusions: An early-intervention, computer-based literacy program can be effective in boosting the phonological skills of 4- to 6-year-olds, particularly if these literacy difficulties are not linked to phonological working memory deficits.

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L’objectif principal de cette thèse était d’obtenir, via l’électrophysiologie cognitive, des indices de fonctionnement post-traumatisme craniocérébral léger (TCCL) pour différents niveaux de traitement de l’information, soit l’attention sélective, les processus décisionnels visuoattentionnels et les processus associés à l’exécution d’une réponse volontaire. L’hypothèse centrale était que les mécanismes de production des lésions de même que la pathophysiologie caractérisant le TCCL engendrent des dysfonctions visuoattentionnelles, du moins pendant la période aiguë suivant le TCCL (i.e. entre 1 et 3 mois post-accident), telles que mesurées à l’aide d’un nouveau paradigme électrophysiologique conçu à cet effet. Cette thèse présente deux articles qui décrivent le travail effectué afin de rencontrer ces objectifs et ainsi vérifier les hypothèses émises. Le premier article présente la démarche réalisée afin de créer une nouvelle tâche d’attention visuospatiale permettant d’obtenir les indices électrophysiologiques (amplitude, latence) et comportementaux (temps de réaction) liés aux processus de traitement visuel et attentionnel précoce (P1, N1, N2-nogo, P2, Ptc) à l’attention visuelle sélective (N2pc, SPCN) et aux processus décisionnels (P3b, P3a) chez un groupe de participants sains (i.e. sans atteinte neurologique). Le deuxième article présente l’étude des effets persistants d’un TCCL sur les fonctions visuoattentionelles via l’obtention des indices électrophysiologiques ciblés (amplitude, latence) et de données comportementales (temps de réaction à la tâche et résultats aux tests neuropsychologiques) chez deux cohortes d’individus TCCL symptomatiques, l’une en phase subaigüe (3 premiers mois post-accident), l’autre en phase chronique (6 mois à 1 an post-accident), en comparaison à un groupe de participants témoins sains. Les résultats des articles présentés dans cette thèse montrent qu’il a été possible de créer une tâche simple qui permet d’étudier de façon rapide et peu coûteuse les différents niveaux de traitement de l’information impliqués dans le déploiement de l’attention visuospatiale. Par la suite, l’utilisation de cette tâche auprès d’individus atteints d’un TCCL testés en phase sub-aiguë ou en phase chronique a permis d’objectiver des profils d’atteintes et de récupération différentiels pour chacune des composantes étudiées. En effet, alors que les composantes associées au traitement précoce de l’information visuelle (P1, N1, N2) étaient intactes, certaines composantes attentionnelles (P2) et cognitivo-attentionnelles (P3a, P3b) étaient altérées, suggérant une dysfonction au niveau des dynamiques spatio-temporelles de l’attention, de l’orientation de l’attention et de la mémoire de travail, à court et/ou à long terme après le TCCL, ceci en présence de déficits neuropsychologiques en phase subaiguë surtout et d’une symptomatologie post-TCCL persistante. Cette thèse souligne l’importance de développer des outils diagnostics sensibles et exhaustifs permettant d’objectiver les divers processus et sous-processus cognitifs susceptible d’être atteints après un TCCL.

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TORT, A. B. L. ; SCHEFFER-TEIXEIRA, R ; Souza, B.C. ; DRAGUHN, A. ; BRANKACK, J. . Theta-associated high-frequency oscillations (110-160 Hz) in the hippocampus and neocortex. Progress in Neurobiology , v. 100, p. 1-14, 2013.

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Several lines of evidence converge to the idea that rapid eye movement sleep (REMS) is a good model to foster our understanding of psychosis. Both REMS and psychosis course with internally generated perceptions and lack of rational judgment, which is attributed to a hyperlimbic activity along with hypofrontality. Interestingly, some individuals can become aware of dreaming during REMS, a particular experience known as lucid dreaming (LD), whose neurobiological basis is still controversial. Since the frontal lobe plays a role in self-consciousness, working memory and attention, here we hypothesize that LD is associated with increased frontal activity during REMS. A possible way to test this hypothesis is to check whether transcranial magnetic or electric stimulation of the frontal region during REMS triggers LD. We further suggest that psychosis and LD are opposite phenomena: LD as a physiological awakening while dreaming due to frontal activity, and psychosis as a pathological intrusion of dream features during wake state due to hypofrontality. We further suggest that LD research may have three main clinical implications. First, LD could be important to the study of consciousness, including its pathologies and other altered states. Second, LD could be used as a therapy for recurrent nightmares, a common symptom of depression and post-traumatic stress disorder. Finally, LD may allow for motor imagery during dreaming with possible improvement of physical rehabilitation. In all, we believe that LD research may clarify multiple aspects of brain functioning in its physiological, altered and pathological states.

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RESUMO Objetivos. O défice mnésico é uma das alterações cognitivas que mais afeta as pessoas idosas. A idade é considerada um dos fatores de relevo nas alterações de memória, inclusivamente pelas próprias pessoas idosas. A investigação tem mostrado que existem outros fatores além da idade que afetam a memória das pessoas idosas. Contudo, fica por esclarecer qual o real papel da idade sobre a memória quando é controlada a influência de outras variáveis. Assim, o presente estudo pretende analisar o impacto da idade no funcionamento mnésico de pessoas idosas e verificar se, ao controlar o papel de outras variáveis (sexo, escolaridade, profissão, situação civil, situação residencial e situação clínica), esse potencial impacto se mantém. Métodos. A amostra global foi constituída por 1126 participantes (283 homens e 843 mulheres; 226 residentes na comunidade e 900 em resposta social dirigida à população idosa) com idades compreendidas entre os 60 e os 100 anos. A avaliação foi realizada com recurso aos itens do Mini-Mental State Examination (memória de trabalho), o fator do Montreal Cognitive Assessment (memória declarativa verbal) e Figura Complexa de ReyOsterrieth (memória visuoespacial). Resultados. Globalmente, a idade, escolaridade, profissão, situação civil, residencial e clínica influenciaram a memória de forma diferenciada consoante o tipo de memória. As análises de regressão hierárquica mostraram que a idade é um fator preditivo em todos os tipos de memória. Emergiram ainda outros fatores preditivos com coeficientes de regressão superiores à idade conforme o tipo de memória (exceto na memória de trabalho). Conclusões. A idade, a escolaridade e a profissão influenciam a memória, assim como os fatores que potencialmente estimulam cognitiva e socialmente (como ter um companheiro e residir na comunidade). Os resultados apontam para a importância de intervir em pessoas em respostas sociais, mais idosas, sem companheiro, com baixa escolaridade e profissão manual. ABSTRACT Goals. Memory impairment is one of the types of cognitive impairment that most affects the elderly. Age is considered one of the major factors in memory impairment, including by the elderly themselves. Research has shown that there are other factors affecting memory of elderly persons. It remains, however, unclear what is the real impact of age in memory when controlling the influence of other variables. Thus, this study aims to analyze the impact of age on memory functioning of elderly persons and check if the potential impact remains when controlling the role of other variables (sex, education, profession, marital status, residential status, and clinical situation). Methods. The global sample comprised 1126 subjects (283 men and 843 women, 226 residents in the community and 900 institutionalized elderly) aged from 60 to 100 years. The assessment included items from the MiniMental State Examination (working memory), the Montreal Cognitive Assessment factor (verbal declarative memory), and Rey-Osterrieth Complex Figure (visuospatial memory). Results. Overall, age, education, profession, marital, residential, and clinical condition have differently influenced memory, depending on the type of memory. The hierarchical regression analysis showed that age is a predictive factor in all types of memory. However, other predictors have emerged with higher regression coefficients compared to age, according to the type of memory (except in working memory). Conclusions. Age, education and profession influence memory, as well as factors that potentially stimulate cognitively and socially (like having a partner and living in the community). The results indicate the importance of intervening, especially among institutionalized elderly, older, unmarried, with low education, and manual profession.

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TORT, A. B. L. ; SCHEFFER-TEIXEIRA, R ; Souza, B.C. ; DRAGUHN, A. ; BRANKACK, J. . Theta-associated high-frequency oscillations (110-160 Hz) in the hippocampus and neocortex. Progress in Neurobiology , v. 100, p. 1-14, 2013.

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The main purpose of the current study was to examine the role of vocabulary knowledge (VK) and syntactic knowledge (SK) in L2 listening comprehension, as well as their relative significance. Unlike previous studies, the current project employed assessment tasks to measure aural and proceduralized VK and SK. In terms of VK, to avoid under-representing the construct, measures of both breadth (VB) and depth (VD) were included. Additionally, the current study examined the role of VK and SK by accounting for individual differences in two important cognitive factors in L2 listening: metacognitive knowledge (MK) and working memory (WM). Also, to explore the role of VK and SK more fully, the current study accounted for the negative impact of anxiety on WM and L2 listening. The study was carried out in an English as a Foreign Language (EFL) context, and participants were 263 Iranian learners at a wide range of English proficiency from lower-intermediate to advanced. Participants took a battery of ten linguistic, cognitive and affective measures. Then, the collected data were subjected to several preliminary analyses, but structural equation modeling (SEM) was then used as the primary analysis method to answer the study research questions. Results of the preliminary analyses revealed that MK and WM were significant predictors of L2 listening ability; thus, they were kept in the main SEM analyses. The significant role of WM was only observed when the negative effect of anxiety on WM was accounted for. Preliminary analyses also showed that VB and VD were not distinct measures of VK. However, the results also showed that if VB and VD were considered separate, VD was a better predictor of L2 listening success. The main analyses of the current study revealed a significant role for both VK and SK in explaining success in L2 listening comprehension, which differs from findings from previous empirical studies. However, SEM analysis did not reveal a statistically significant difference in terms of the predictive power of the two linguistic factors. Descriptive results of the SEM analysis, along with results from regression analysis, indicated to a more significant role for VK.

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Dissertação de Mestrado, Ciências Biomédicas, 28 de Junho de 2016, Universidade dos Açores.

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Several lines of evidence converge to the idea that rapid eye movement sleep (REMS) is a good model to foster our understanding of psychosis. Both REMS and psychosis course with internally generated perceptions and lack of rational judgment, which is attributed to a hyperlimbic activity along with hypofrontality. Interestingly, some individuals can become aware of dreaming during REMS, a particular experience known as lucid dreaming (LD), whose neurobiological basis is still controversial. Since the frontal lobe plays a role in self-consciousness, working memory and attention, here we hypothesize that LD is associated with increased frontal activity during REMS. A possible way to test this hypothesis is to check whether transcranial magnetic or electric stimulation of the frontal region during REMS triggers LD. We further suggest that psychosis and LD are opposite phenomena: LD as a physiological awakening while dreaming due to frontal activity, and psychosis as a pathological intrusion of dream features during wake state due to hypofrontality. We further suggest that LD research may have three main clinical implications. First, LD could be important to the study of consciousness, including its pathologies and other altered states. Second, LD could be used as a therapy for recurrent nightmares, a common symptom of depression and post-traumatic stress disorder. Finally, LD may allow for motor imagery during dreaming with possible improvement of physical rehabilitation. In all, we believe that LD research may clarify multiple aspects of brain functioning in its physiological, altered and pathological states.

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The Internet has grown in size at rapid rates since BGP records began, and continues to do so. This has raised concerns about the scalability of the current BGP routing system, as the routing state at each router in a shortest-path routing protocol will grow at a supra-linearly rate as the network grows. The concerns are that the memory capacity of routers will not be able to keep up with demands, and that the growth of the Internet will become ever more cramped as more and more of the world seeks the benefits of being connected. Compact routing schemes, where the routing state grows only sub-linearly relative to the growth of the network, could solve this problem and ensure that router memory would not be a bottleneck to Internet growth. These schemes trade away shortest-path routing for scalable memory state, by allowing some paths to have a certain amount of bounded “stretch”. The most promising such scheme is Cowen Routing, which can provide scalable, compact routing state for Internet routing, while still providing shortest-path routing to nearly all other nodes, with only slightly stretched paths to a very small subset of the network. Currently, there is no fully distributed form of Cowen Routing that would be practical for the Internet. This dissertation describes a fully distributed and compact protocol for Cowen routing, using the k-core graph decomposition. Previous compact routing work showed the k-core graph decomposition is useful for Cowen Routing on the Internet, but no distributed form existed. This dissertation gives a distributed k-core algorithm optimised to be efficient on dynamic graphs, along with with proofs of its correctness. The performance and efficiency of this distributed k-core algorithm is evaluated on large, Internet AS graphs, with excellent results. This dissertation then goes on to describe a fully distributed and compact Cowen Routing protocol. This protocol being comprised of a landmark selection process for Cowen Routing using the k-core algorithm, with mechanisms to ensure compact state at all times, including at bootstrap; a local cluster routing process, with mechanisms for policy application and control of cluster sizes, ensuring again that state can remain compact at all times; and a landmark routing process is described with a prioritisation mechanism for announcements that ensures compact state at all times.

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L’objectif principal de cette thèse était d’obtenir, via l’électrophysiologie cognitive, des indices de fonctionnement post-traumatisme craniocérébral léger (TCCL) pour différents niveaux de traitement de l’information, soit l’attention sélective, les processus décisionnels visuoattentionnels et les processus associés à l’exécution d’une réponse volontaire. L’hypothèse centrale était que les mécanismes de production des lésions de même que la pathophysiologie caractérisant le TCCL engendrent des dysfonctions visuoattentionnelles, du moins pendant la période aiguë suivant le TCCL (i.e. entre 1 et 3 mois post-accident), telles que mesurées à l’aide d’un nouveau paradigme électrophysiologique conçu à cet effet. Cette thèse présente deux articles qui décrivent le travail effectué afin de rencontrer ces objectifs et ainsi vérifier les hypothèses émises. Le premier article présente la démarche réalisée afin de créer une nouvelle tâche d’attention visuospatiale permettant d’obtenir les indices électrophysiologiques (amplitude, latence) et comportementaux (temps de réaction) liés aux processus de traitement visuel et attentionnel précoce (P1, N1, N2-nogo, P2, Ptc) à l’attention visuelle sélective (N2pc, SPCN) et aux processus décisionnels (P3b, P3a) chez un groupe de participants sains (i.e. sans atteinte neurologique). Le deuxième article présente l’étude des effets persistants d’un TCCL sur les fonctions visuoattentionelles via l’obtention des indices électrophysiologiques ciblés (amplitude, latence) et de données comportementales (temps de réaction à la tâche et résultats aux tests neuropsychologiques) chez deux cohortes d’individus TCCL symptomatiques, l’une en phase subaigüe (3 premiers mois post-accident), l’autre en phase chronique (6 mois à 1 an post-accident), en comparaison à un groupe de participants témoins sains. Les résultats des articles présentés dans cette thèse montrent qu’il a été possible de créer une tâche simple qui permet d’étudier de façon rapide et peu coûteuse les différents niveaux de traitement de l’information impliqués dans le déploiement de l’attention visuospatiale. Par la suite, l’utilisation de cette tâche auprès d’individus atteints d’un TCCL testés en phase sub-aiguë ou en phase chronique a permis d’objectiver des profils d’atteintes et de récupération différentiels pour chacune des composantes étudiées. En effet, alors que les composantes associées au traitement précoce de l’information visuelle (P1, N1, N2) étaient intactes, certaines composantes attentionnelles (P2) et cognitivo-attentionnelles (P3a, P3b) étaient altérées, suggérant une dysfonction au niveau des dynamiques spatio-temporelles de l’attention, de l’orientation de l’attention et de la mémoire de travail, à court et/ou à long terme après le TCCL, ceci en présence de déficits neuropsychologiques en phase subaiguë surtout et d’une symptomatologie post-TCCL persistante. Cette thèse souligne l’importance de développer des outils diagnostics sensibles et exhaustifs permettant d’objectiver les divers processus et sous-processus cognitifs susceptible d’être atteints après un TCCL.

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Little is known about the functional and neural architecture of social reasoning, one major obstacle being that we crucially lack the relevant tools to test potentially different social reasoning components. In the case of belief reasoning, previous studies tried to separate the processes involved in belief reasoning per se from those involved in the processing of the high incidental demands such as the working memory demands of typical belief tasks (e.g., Stone et al., 1998; Samson et al., 2004). In this study, we developed new belief tasks in order to disentangle, for the first time, two perspective taking components involved in belief reasoning: (1) the ability to inhibit one’s own perspective (self-perspective inhibition) and (2) the ability to infer someone else’s perspective as such (other-perspective taking). The two tasks had similar demands in other-perspective taking as they both required the participant to infer that a character has a false belief about an object’s location. However, the tasks varied in the self-perspective inhibition demands. In the task with the lowest self-perspective inhibition demands, at the time the participant had to infer the character’s false belief, he or she had no idea what the new object’s location was. In contrast, in the task with the highest self-perspective inhibition demands, at the time the participant had to infer the character’s false belief, he or she knew where the object was actually located (and this knowledge had thus to be inhibited). The two tasks were presented to a stroke patient, WBA, with right prefrontal and temporal damage. WBA performed well in the low-inhibition false belief task but showed striking difficulty in the task placing high self-perspective inhibition demands, showing a selective deficit in inhibiting self-perspective. WBA also made egocentric errors in other social and visual perspective taking tasks, indicating a difficulty with belief attribution extending to the attribution of emotions, desires and visual experiences to other people. The case of WBA, together with the recent report of three patients impaired in belief reasoning even when self-perspective inhibition demands were reduced (Samson et al., 2004), provide the first neuropsychological evidence that (a) the inhibition of one’s own point of view and (b) the ability to infer someone else’ s point of view, rely on distinct neural and functional processes.

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Objetivos: O presente estudo teve como primeiro objetivo estudar Funcionamento Executivo na Perturbação de Hiperatividade e Défice de Atenção (PHDA) e, como segundo, analisar o potencial das vinhetas como instrumento de avaliação ecológica nas Funções Executivas. Métodos: Neste estudo participaram 15 Pais de crianças com PHDA, com idades compreendidas entre o 6 e os 16 anos. As crianças foram avaliadas quantitativamente e qualitativamente pelos Pais. Quantitativamente foram avaliados nos 8 domínios específicos do Funcionamento Executivo: Controlo Inibitório, Flexibilidade, Controlo Emocional, Iniciativa, Memória de Trabalho, Planeamento/Organização, Organização de Materiais e Monitorização e nas subescalas do instrumento de avaliação. Qualitativamente foram avaliados a partir de vinhetas com situações do dia-a-dia. Para a avaliação das Funções Executivas foi utilizado o instrumento de avaliação ICAFE – P - Inventário Comportamental de Avaliação das Funções Executivas – Versão para Pais. Resultados: Os resultados sugerem que as maiores dificuldades no quotidiano se relacionam com vulnerabilidades na Memória de Trabalho. Parecem não existir grandes diferenças nas respostas dos pais em função do género. Já no que refere à faixa etária, os pais apresentam respostas diferentes. Conclusões: Constatou-se que a amostra apresenta, de um modo geral, problemas em todos os domínios presentes nas Funções Executivas. Destacando-se dificuldades acrescidas em situações de memória de trabalho e de planeamento. São necessários mais estudos sobre esta temática e com amostras superiores.

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Dissertação de Mestrado, Neurociências Cognitivas e Neuropsicologia, Faculdade de Ciências Humanas e Sociais, Universidade do Algarve, 2016

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Des études récentes ont rapporté que les individus âgés avec un trouble cognitif léger (TCL) ont de plus grandes activations en lien avec la réalisation d’une tâche cognitive que des personnes âgées saines. Des auteurs ont proposé que ces hyperactivations pourraient refléter des processus de plasticité cérébrale compensatoires ayant lieu pendant la phase précoce de la maladie d’Alzheimer. Des processus de compensations fonctionnelles pourraient émerger en réponse à une perte d’intégrité structurelle dans les régions du cerveau normalement requises pour compléter une tâche. Dans ce mémoire, j’ai évalué cette hypothèse chez des personnes avec TCL en faisant appel à une tâche de mémoire de travail comportant plusieurs niveaux de difficulté ainsi qu’aux techniques d’imagerie par résonnance magnétique (IRM) structurelle et fonctionnelle. Des analyses de régression multiples ont été utilisées afin d’identifier les régions cérébrales dont l’activité variait en fonction de l’intégrité neuronale telle que définie par le volume de l’hippocampe. Les valeurs estimées des paramètres du signal de ces régions furent ensuite extraites afin de procéder à des analyses corrélationnelles sur la performance ainsi que sur le volume de différentes structures cérébrales. Les résultats indiquent des hyperactivations dans les régions frontales droites chez les participants TCL souffrant d’une plus grande atteinte neuronale. De plus, le niveau d’activation est négativement corrélé au volume de structures frontales et pariétales. Ces résultats indique la présence d’une hyperactivation compensatoire dans la phase du TCL associée à la réalisation d’une tâche de mémoire de travail.