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Fluência semântica, fonêmica e de verbos em indivíduos com comprometimento cognitivo leve; Semantic, phonemic and verb fluency in individuals with mild cognitive impairment

Steiner, Veronique Agnes Guernet
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 11/12/2013 Português
Relevância na Pesquisa
36.39%
INTRODUÇÃO: A identificação precoce de risco de desenvolver processos demenciais é importante para que os indivíduos possam beneficiar-se de ações dirigidas a aspectos cognitivos e funcionais. Provas de fluência verbal são geralmente incluídas nas avaliações para o diagnóstico precoce da doença de Alzheimer, pois contribuem para detectar alterações de linguagem e de funções executivas. As provas de fluência verbal mais frequentemente utilizadas são as de fluência semântica (FS) e fonêmica (FF) que solicitam respectivamente a emissão em um minuto do maior número de palavras que pertencem a uma determinada categoria semântica ou que começam com uma letra específica. Estudos recentes têm mostrado que, com relação à FS e à FF, as provas de fluência de verbos (FVe) "coisas que as pessoas podem fazer" são tarefas mais sensíveis para detectar precocemente alterações cognitivas em indivíduos com comprometimento cognitivo leve (CCL). No entanto, estes dados precisam ser replicados. Em contraste com a maioria das pesquisas que analisa o número total de palavras produzidas em um minuto, o estudo do desempenho segundo o modelo de distribuição temporal do comportamento verifica a variação do número de palavras produzidas nos quartis sucessivos de 15 segundos. Este método pode auxiliar a compreender o papel destas tarefas como instrumento diagnóstico. Como este modelo preconiza que...

A organização hierárquica do conhecimento semântico em pacientes com afasia : o papel da partilha de atributos e função executiva

Martins, Maria Eugénia Canhão, 1985-
Fonte: Universidade de Lisboa Publicador: Universidade de Lisboa
Tipo: Dissertação de Mestrado
Publicado em //2013 Português
Relevância na Pesquisa
26.37%
Tese de mestrado, Ciência Cognitiva, Universidade de Lisboa, Faculdade de Psicologia, Faculdade de Ciências, Faculdade de Medicina, Faculdade de Letras, 2013; Vários estudos têm sido realizados sobre a organização hierárquica da memória semântica pela análise de défices semânticos em pacientes com vários distúrbios neurológicos, tais como pacientes com demência semântica e pacientes com afasia devido a acidente vascular cerebral (AVC) e com défices executivos. Os pacientes com demência semântica apresentam uma degradação do conhecimento semântico com prevalência do conhecimento sobreordenado (ex. animal, veículo) e maior comprometimento do conhecimento de nível básico (ex. elefante, camião). Os pacientes com afasia revelam um desempenho oposto com prevalência do conhecimento de nível básico. Estes últimos casos têm destacado a contribuição de processos executivos para a cognição semântica, nomeadamente para dirigir e controlar a ativação semântica de forma apropriada. Estes dois tipos de défices semânticos, parecem poder ser explicados pela partilha de atributos (Marques, 2011, 2012). Esta dimensão pode explicar a vantagem do nível sobreordenado na demência semântica pois estes conceitos reúnem um maior número absoluto de exemplares que partilham uma característica particular...

A fluência verbal na perturbação do espectro do autismo : processos executivos, análise temporal e tipicidade

Duarte, Elsa Margarida Rodrigues Dias, 1975-
Fonte: Universidade de Lisboa Publicador: Universidade de Lisboa
Tipo: Dissertação de Mestrado
Publicado em //2014 Português
Relevância na Pesquisa
26.32%
Tese de mestrado, Ciência Cognitiva, Universidade de Lisboa, Faculdade de Ciências, Faculdade de Letras, Faculdade de Medicina, Faculdade de Psicologia, 2014; A fluência verbal é uma tarefa cognitiva complexa que envolve processos linguísticos, mnésicos e executivos. As análises quantitativas, qualitativas e temporais da fluência verbal, assim como do nível de tipicidade das respostas produzidas, podem contribuir para a compreensão dos processos cognitivos característicos dos indivíduos com Perturbação do Espectro do Autismo (PEA). No presente estudo foi comparado o desempenho na fluência verbal fonémica (letras “P”, “M”, “R”) e na fluência verbal semântica (“animais”, “frutos”, “vestuário”), em adultos com Perturbação do Espetro do Autismo (n = 20) e um grupo de controlo neurotípico (n = 20). Todos os participantes foram pareados por idade, género, QI verbal e nível de escolaridade. Os resultados mostraram que os participantes com Perturbação do Espetro do Autismo (PEA) foram significativamente comprometidos no seu desempenho em ambos os testes de fluência verbal (fonémica e semântica), com uma produção de palavras inferior ao grupo de controlo. Relativamente às estratégias de agrupamento (semântico) e alternância (não semântico) não ocorreram diferenças estatisticamente significativas entre os grupos de estudo...

WCST and NEUPSILIN: relationships among executive functions, attention, memory and language

Yates,Denise Balem; Zibetti,Murilo Ricardo; Pawlowski,Josiane; Salles,Jerusa Fumagalli; Parente,Maria Alice de Mattos Pimenta; Argimon,Irani de Lima; Fonseca,Rochele Paz; Trentini,Clarissa Marceli
Fonte: Curso de Pós-Graduação em Psicologia da Universidade Federal do Rio Grande do Sul Publicador: Curso de Pós-Graduação em Psicologia da Universidade Federal do Rio Grande do Sul
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2013 Português
Relevância na Pesquisa
46.03%
This study investigated the relationship between measures of the Wisconsin Card Sorting Test (WCST) and a brief battery of cognitive functions (NEUPSILIN) with the goal of providing a better understanding of the association between executive processes and other functions. The sample included 39 people, from 14 to 61 years old, with an average education of 12.38 (SD = 3.65) years of study. The hypothesis that correlations would be moderate to strong between the measures of executive function, working memory, attention and prospective memory from NEUPSILIN and WCST scores was partially corroborated because the intensity of the correlations was below than the expected. Other correlations were also found between the WCST scores and tasks that assess semantic-episodic memory, oral language (inference processing) and writing (reading) components.

Deficits of knowledge vs. executive control in semantic cognition: Insights from cued naming

Jefferies, Elizabeth; Patterson, Karalyn; Lambon Ralph, Matthew A.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
36.23%
Deficits of semantic cognition in semantic dementia and in aphasia consequent on CVA (stroke) are qualitatively different. Patients with semantic dementia are characterised by progressive degradation of central semantic representations, whereas multimodal semantic deficits in stroke aphasia reflect impairment of executive processes that help to direct and control semantic activation in a task-appropriate fashion (Jefferies and Lambon Ralph, 2006). We explored interactions between these two aspects of semantic cognition by examining the effects of cumulative phonemic cueing on picture naming in case series of these two types of patient. The stroke aphasic patients with multimodal semantic deficits cued very readily and demonstrated near-perfect name retrieval when cumulative phonemic cues reached or exceeded the target name’s uniqueness point. Therefore, knowledge of the picture names was largely intact for the aphasic patients, but they were unable to retrieve this information without cues that helped to direct activation towards the target response. Equivalent phonemic cues engendered significant but much more limited benefit to the semantic dementia patients: their naming was still severely impaired even when most of the word had been provided. In contrast to the pattern in the stroke aphasia group...

Semantic and self-referential processing of positive and negative trait adjectives in older adults

Glisky, Elizabeth L.; Marquine, Maria J.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /02/2009 Português
Relevância na Pesquisa
26.15%
The beneficial effects of self-referential processing on memory have been demonstrated in numerous experiments with younger adults but have rarely been studied in older individuals. In the present study we tested young people, younger-older adults, and older-older adults in a self-reference paradigm, and compared self-referential processing to general semantic processing. Findings indicated that older adults over the age of 75 and those with below average episodic memory function showed a decreased benefit from both semantic and self-referential processing relative to a structural baseline condition. However, these effects appeared to be confined to the shared semantic processes for the two conditions, leaving the added advantage for self-referential processing unaffected These results suggest that reference to the self engages qualitatively different processes compared to general semantic processing. These processes seem relatively impervious to age and to declining memory and executive function, suggesting that they might provide a particularly useful way for older adults to improve their memories.

The Modulatory Influence of the Functional COMT Val158Met Polymorphism on Lexical Decisions and Semantic Priming

Reuter, Martin; Montag, Christian; Peters, Kristina; Kocher, Anne; Kiefer, Markus
Fonte: Frontiers Research Foundation Publicador: Frontiers Research Foundation
Tipo: Artigo de Revista Científica
Publicado em 24/08/2009 Português
Relevância na Pesquisa
26.23%
The role of the prefrontal Cortex (PFC) in higher cognitive functions – including working memory, conflict resolution, set shifting and semantic processing – has been demonstrated unequivocally. Despite the great heterogeneity among tasks measuring these phenotypes, due in part to the different cognitive sub-processes implied and the specificity of the stimulus material used, there is agreement that all of these tasks recruit an executive control system located in the PFC. On a biochemical level it is known that the dopaminergic system plays an important role in executive control functions. Evidence comes from molecular genetics relating the functional COMT Val158Met polymorphism to working memory and set shifting. In order determine whether this pattern of findings generalises to linguistic and semantic processing, we investigated the effects of the COMT Val158Met polymorphism in lexical decision making using masked and unmasked versions of the semantic priming paradigm on N = 104 healthy subjects. Although we observed strong priming effects in all conditions (masked priming, unmasked priming with short/long stimulus asynchronies (SOAs), direct and indirect priming), COMT was not significantly related to priming, suggesting no reliable influence on semantic processing. However...

Neural differences in the processing of semantic relationships across cultures

Gutchess, Angela H.; Hedden, Trey; Ketay, Sarah; Aron, Arthur; Gabrieli, John D.E.
Fonte: Oxford University Press Publicador: Oxford University Press
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
36.23%
The current study employed functional MRI to investigate the contribution of domain-general (e.g. executive functions) and domain-specific (e.g. semantic knowledge) processes to differences in semantic judgments across cultures. Previous behavioral experiments have identified cross-cultural differences in categorization, with East Asians preferring strategies involving thematic or functional relationships (e.g. cow-grass) and Americans preferring categorical relationships (e.g. cow-chicken). East Asians and American participants underwent functional imaging while alternating between categorical or thematic strategies to sort triads of words, as well as matching words on control trials. Many similarities were observed. However, across both category and relationship trials compared to match (control) trials, East Asians activated a frontal-parietal network implicated in controlled executive processes, whereas Americans engaged regions of the temporal lobes and the cingulate, possibly in response to conflict in the semantic content of information. The results suggest that cultures differ in the strategies employed to resolve conflict between competing semantic judgments.

Heterogeneity of the Left Temporal Lobe in Semantic Representation and Control: Priming Multiple versus Single Meanings of Ambiguous Words

Whitney, Carin; Jefferies, Elizabeth; Kircher, Tilo
Fonte: Oxford University Press Publicador: Oxford University Press
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
36.29%
Semantic judgments involve both representations of meaning plus executive mechanisms that guide knowledge retrieval in a task-appropriate way. These 2 components of semantic cognition—representation and control—are commonly linked to left temporal and prefrontal cortex, respectively. This simple proposal, however, remains contentious because in most functional neuroimaging studies to date, the number of concepts being activated and the involvement of executive processes during retrieval are confounded. Using functional magnetic resonance imaging, we examined a task in which semantic representation and control demands were dissociable. Words with multiple meanings like “bank” served as targets in a double-prime paradigm, in which multiple meaning activation and maximal executive demands loaded onto different priming conditions. Anterior inferior temporal gyrus (ITG) was sensitive to the number of meanings that were retrieved, suggesting a role for this region in semantic representation, while posterior middle temporal gyrus (pMTG) and inferior frontal cortex showed greater activation in conditions that maximized executive demands. These results support a functional dissociation between left ITG and pMTG, consistent with a revised neural organization in which left prefrontal and posterior temporal areas work together to underpin aspects of semantic control.

Executive control over unconscious cognition: attentional sensitization of unconscious information processing

Kiefer, Markus
Fonte: Frontiers Media S.A. Publicador: Frontiers Media S.A.
Tipo: Artigo de Revista Científica
Publicado em 23/03/2012 Português
Relevância na Pesquisa
26.15%
Unconscious priming is a prototypical example of an automatic process, which is initiated without deliberate intention. Classical theories of automaticity assume that such unconscious automatic processes occur in a purely bottom-up driven fashion independent of executive control mechanisms. In contrast to these classical theories, our attentional sensitization model of unconscious information processing proposes that unconscious processing is susceptible to executive control and is only elicited if the cognitive system is configured accordingly. It is assumed that unconscious processing depends on attentional amplification of task-congruent processing pathways as a function of task sets. This article provides an overview of the latest research on executive control influences on unconscious information processing. I introduce refined theories of automaticity with a particular focus on the attentional sensitization model of unconscious cognition which is specifically developed to account for various attentional influences on different types of unconscious information processing. In support of the attentional sensitization model, empirical evidence is reviewed demonstrating executive control influences on unconscious cognition in the domains of visuo-motor and semantic processing: subliminal priming depends on attentional resources...

Combined Effects of Aging and HIV Infection on Semantic Verbal Fluency: A View of the Cortical Hypothesis Through the Lens of Clustering and Switching

Iudicello, Jennifer E.; Woods, Steven Paul; Deutsch, Reena; Grant, Igor;
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
26.2%
The profile of HIV-associated neurocognitive disorders (HAND) has classically been characterized as “subcortical”, but questions have arisen as to whether aging with HIV in the antiretroviral therapy era has subtlety shifted the expression of HAND into a more “cortical” disorder (e.g., decay of semantic memory stores). We evaluated this hypothesis by examining semantic fluency and its component processes (i.e., clustering and switching) in 257 individuals across four groups stratified by age (<40 and ≥ 50 years) and HIV serostatus. Jonckheere-Terpstra tests revealed significant monotonic trends for the combined effects of HIV and aging on overall semantic (and letter) fluency and switching, but not cluster size, with greatest deficits evident in the older adults with HIV infection. Within the older HIV-infected cohort, poorer switching was uniquely associated with self-reported declines in instrumental activities of daily living and deficits in learning and executive functions, but not semantic memory. Results suggest that HIV infection and aging may confer adverse additive effects on the executive components of semantic fluency (i.e., switching), rather than a degradation of semantic memory stores (i.e., cluster size), which is a profile that is most consistent with combined frontostriatal neuropathological burden of these two conditions.

Differential Trajectories of Age-Related Changes in Components of Executive and Memory Processes

Goh, Joshua O.; An, Yang; Resnick, Susan M.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
26.17%
Several studies have demonstrated age-related declines in general executive function and memory. In this study, we examined cross-sectional and longitudinal age effects in more specific cognitive processes that constitute executive function and memory. We postulated that, whereas some components of executive and memory functions would show age differences and longitudinal declines, other specific abilities would be maintained or even improve with repeated testing. In a sample of individuals ≥55 years old from the Baltimore Longitudinal Study of Aging, we found longitudinal declines in inhibition, manipulation, semantic retrieval, phonological retrieval, switching, and long-term memory over a maximum of 14 years follow-up. In contrast, abstraction, capacity, chunking, discrimination, and short-term memory were maintained or even improved longitudinally, probably due in part to repeated testing. Moreover, whereas several different abilities were correlated across participants’ cross-sectional performance, longitudinal changes in performance showed more heterogeneous trajectories. Finally, compared with cross-sectional performance, longitudinal trajectories showed better distinction between participants with and those without later cognitive impairment. These results show that longitudinal cognitive aging of executive and memory functions is not a uniform process but a heterogeneous one and suggest that certain executive and memory functions remain stable despite age-related declines in other component processes.

Age-related vulnerability in the neural systems supporting semantic processing

Peelle, Jonathan E.; Chandrasekaran, Keerthi; Powers, John; Smith, Edward E.; Grossman, Murray
Fonte: Frontiers Media S.A. Publicador: Frontiers Media S.A.
Tipo: Artigo de Revista Científica
Publicado em 12/09/2013 Português
Relevância na Pesquisa
36.19%
Our ability to form abstract representations of objects in semantic memory is crucial to language and thought. The utility of this information relies both on the representations of sensory-motor feature knowledge stored in long-term memory and the executive processes required to retrieve, manipulate, and evaluate this semantic knowledge in a task-relevant manner. These complementary components of semantic memory can be differentially impacted by aging. We investigated semantic processing in normal aging using functional magnetic resonance imaging (fMRI). Young and older adults were asked to judge whether two printed object names match on a particular feature (for example, whether a tomato and strawberry have the same color). The task thus required both retrieval of relevant visual feature knowledge of object concepts and evaluating this information. Objects were drawn from either natural kinds or manufactured objects, and were queried on either color or shape in a factorial design. Behaviorally, all subjects performed well, but older adults could be divided into those whose performance matched that of young adults (better performers) and those whose performance was worse (poorer performers). All subjects activated several cortical regions while performing this task...

Age-Related Changes in the Functional Network Underlying Specific and General Autobiographical Memory Retrieval: A Pivotal Role for the Anterior Cingulate Cortex

Martinelli, Pénélope; Sperduti, Marco; Devauchelle, Anne-Dominique; Kalenzaga, Sandrine; Gallarda, Thierry; Lion, Stéphanie; Delhommeau, Marion; Anssens, Adèle; Amado, Isabelle; Meder, Jean François; Krebs, Marie-Odile; Oppenheim, Catherine; Piolino,
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 18/12/2013 Português
Relevância na Pesquisa
26.25%
Age-related changes in autobiographical memory (AM) recall are characterized by a decline in episodic details, while semantic aspects are spared. This deleterious effect is supposed to be mediated by an inefficient recruitment of executive processes during AM retrieval. To date, contrasting evidence has been reported on the neural underpinning of this decline, and none of the previous studies has directly compared the episodic and semantic aspects of AM in elderly. We asked 20 young and 17 older participants to recall specific and general autobiographical events (i.e., episodic and semantic AM) elicited by personalized cues while recording their brain activity by means of fMRI. At the behavioral level, we confirmed that the richness of episodic AM retrieval is specifically impoverished in aging and that this decline is related to the reduction of executive functions. At the neural level, in both age groups, we showed the recruitment of a large network during episodic AM retrieval encompassing prefrontal, cortical midline and posterior regions, and medial temporal structures, including the hippocampus. This network was very similar, but less extended, during semantic AM retrieval. Nevertheless, a greater activity was evidenced in the dorsal anterior cingulate cortex (dACC) during episodic...

Substrats neuronaux du traitement visuel et sémantique des mots dans le vieillissement normal : apports de la MEG

Lacombe, Jacinthe
Fonte: Université de Montréal Publicador: Université de Montréal
Tipo: Thèse ou Mémoire numérique / Electronic Thesis or Dissertation
Português
Relevância na Pesquisa
26.35%
Bien que l’on ait longtemps considéré que les substrats cérébraux de la mémoire sémantique (MS) demeuraient intacts au cours du vieillissement normal (VN), en raison d’une préservation de la performance des personnes âgées à des épreuves sémantiques, plusieurs études récentes suggèrent que des modifications cérébrales sous-tendant le traitement sémantique opèrent au cours du vieillissement. Celles-ci toucheraient principalement les régions responsables des aspects exécutifs du traitement sémantique, impliqués dans les processus de recherche, de sélection et de manipulation stratégique de l’information sémantique. Cependant, les mécanismes spécifiques régissant la réorganisation cérébrale du traitement sémantique au cours du VN demeurent méconnus, notamment en raison de divergences méthodologiques entre les études. De plus, des données de la littérature suggèrent que des modifications cérébrales associées au vieillissement pourraient également avoir lieu en relation avec les aspects perceptifs visuels du traitement des mots. Puisque le processus de lecture des mots représente un processus interactif et dynamique entre les fonctions perceptuelles de bas niveau et les fonctions de plus haut niveau tel que la MS...

Changes in cortical and sub-cortical patterns of activity associated with aging during the performance of a lexical set-shifting task

Martins, Ruben
Fonte: Université de Montréal Publicador: Université de Montréal
Tipo: Thèse ou Mémoire numérique / Electronic Thesis or Dissertation
Português
Relevância na Pesquisa
36.09%
Bien que le passage du temps altère le cerveau, la cognition ne suit pas nécessairement le même destin. En effet, il existe des mécanismes compensatoires qui permettent de préserver la cognition (réserve cognitive) malgré le vieillissement. Les personnes âgées peuvent utiliser de nouveaux circuits neuronaux (compensation neuronale) ou des circuits existants moins susceptibles aux effets du vieillissement (réserve neuronale) pour maintenir un haut niveau de performance cognitive. Toutefois, la façon dont ces mécanismes affectent l’activité corticale et striatale lors de tâches impliquant des changements de règles (set-shifting) et durant le traitement sémantique et phonologique n’a pas été extensivement explorée. Le but de cette thèse est d’explorer comment le vieillissement affecte les patrons d’activité cérébrale dans les processus exécutifs d’une part et dans l’utilisation de règles lexicales d’autre part. Pour cela nous avons utilisé l’imagerie par résonance magnétique fonctionnelle (IRMf) lors de la performance d’une tâche lexicale analogue à celle du Wisconsin. Cette tâche a été fortement liée à de l’activité fronto-stritale lors des changements de règles, ainsi qu’à la mobilisation de régions associées au traitement sémantique et phonologique lors de décisions sémantiques et phonologiques...

Rôle des circuits cortico-striataux dans la planification et l'exécution de règles lexicales

Simard, France
Fonte: Université de Montréal Publicador: Université de Montréal
Tipo: Thèse ou Mémoire numérique / Electronic Thesis or Dissertation
Português
Relevância na Pesquisa
36.05%
Des recherches, autant chez l’homme que chez l’animal, proposent qu’il existerait, au sein des réseaux cérébraux, une organisation anatomique parallèle de circuits qui coordonne l’activité des structures qui participent à la planification et à l’exécution d’une action. Dans cette foulée, un modèle émerge qui attribue au cortex préfrontal (CPF) latéral une spécificité anatomo-fonctionnelle basée sur les niveaux de traitement en mémoire de travail (MT). Il s’agit du modèle « niveaux de traitement-dépendant », qui accorde un rôle important au CPF latéral dans l’acquisition et la représentation de règles guidant nos comportements. Des études en neuroimagerie fonctionnelle, utilisant le Wisconsin Card Sorting Task (WCST) ont permis de corroborer ce modèle et de dissocier trois niveaux de traitement en MT non seulement au sein du CPF latéral mais encore aux structures sous- corticales, les ganglions de la base (GB). Ces études suggèrent que certains noyaux des GB seraient topographiquement organisés avec le CPF latéral et contriburaient, sous certaines conditions, à des processus cognitifs et moteurs semblables à leur homologue cortical. Le but de notre étude est d'explorer la généralisation de la contribution des GB et du CPF au modèle niveaux de traitement-dépendant afin de voir si ce dernier est indépendant de la nature des stimuli en mémoire de travail. À cet effet...

Executive deficits are related to the inferior frontal junction in early dementia

Schroeter, Matthias L.; Vogt, Barbara; Frisch, Stefan; Becker, Georg; Barthel, Henryk; Mueller, Karsten; Villringer, Arno; Sabri, Osama
Fonte: Oxford University Press Publicador: Oxford University Press
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
26.16%
Executive functions describe a wide variety of higher order cognitive processes that allow the flexible modification of thought and behaviour in response to changing cognitive or environmental contexts. Their impairment is common in neurodegenerative disorders. Executive deficits negatively affect everyday activities and hamper the ability to cope with other deficits, such as memory impairment in Alzheimer's disease or behavioural disorders in frontotemporal lobar degeneration. Our study aimed to characterize the neural correlates of executive functions by relating respective deficits to regional hypometabolism in early dementia. Executive functions were assessed with two classical tests, the Stroop and semantic fluency test and various subtests of the behavioural assessment of the dysexecutive syndrome test battery capturing essential aspects of executive abilities relevant to daily living. Impairments in executive functions were correlated with reductions in brain glucose utilization as measured by [18F]fluorodeoxyglucose positron emission tomography and analysed voxelwise using statistical parametric mapping in 54 subjects with early dementia, mainly Alzheimer's disease and frontotemporal lobar degeneration, and its prodromal stages: subjective and mild cognitive impairment. Although the analysis revealed task-specific frontoparietal networks...

Executive demands of the Tower of London task in Brazilian teenagers

Dias,Natália Martins; Seabra,Alessandra Gotuzo
Fonte: Pontificia Universidade Católica do Rio de Janeiro; Universidade de Brasília; Universidade de São Paulo Publicador: Pontificia Universidade Católica do Rio de Janeiro; Universidade de Brasília; Universidade de São Paulo
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2012 Português
Relevância na Pesquisa
36.05%
Some executive tasks may require diverse abilities to solve, having implications for the comprehension of an individual's performance. This study investigated the processes involved in the resolution of a complex test of executive function (EF): the Tower of London (ToL) task. One hundred twenty-four healthy teenagers, 11-14 years old (M = 12.5, SD = 1.14) participated in the study. They were tested using the Auditory Working Memory Test, Visual Working Memory Test, Computerized Stroop Test, Semantic Generation Test, Cancellation Attention Test, and Trail Making Test B, in addition to the ToL. Multivariate analysis showed significant effects of age on visual and auditory working memory, interference control, and planning, with a marginal effect on selective attention. A gender effect was found only on visual working memory where boys scored higher than girls. Significant correlations were found between EF measures despite their low and moderate magnitudes. Performance on the ToL task was correlated with some executive ability measures. The most difficult problems that required four and five moves were more correlated with EF measures than the easier problems that required two and three moves. Regression analyses revealed that only auditory working memory integrated the ToL explanation model after controlling for age. However...

Neural changes associated with semantic processing in healthy aging despite intact behavioral performance

Lacombe, Jacinthe; Jolicoeur, Pierre; Grimault, Stephan; Pineault, Jessica; Joubert, Sven
Fonte: Université de Montréal Publicador: Université de Montréal
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
66.2%
Semantic memory recruits an extensive neural network including the left inferior prefrontal cortex (IPC) and the left temporoparietal region, which are involved in semantic control processes, as well as the anterior temporal lobe region (ATL) which is considered to be involved in processing semantic information at a central level. However, little is known about the underlying neuronal integrity of the semantic network in normal aging. Young and older healthy adults carried out a semantic judgment task while their cortical activity was recorded using magnetoencephalography (MEG). Despite equivalent behavioral performance, young adults activated the left IPC to a greater extent than older adults, while the latter group recruited the temporoparietal region bilaterally and the left ATL to a greater extent than younger adults. Results indicate that significant neuronal changes occur in normal aging, mainly in regions underlying semantic control processes, despite an apparent stability in performance at the behavioral level.