867 resultados para WORKING MEMORY


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In this study we aim to evaluate the impact of ageing and gender on different visual mental imagery processes. Two hundred and fifty-one participants (130 women and 121 men; age range = 18–77 years) were given an extensive neuropsychological battery including tasks probing the generation, maintenance, inspection, and transformation of visual mental images (Complete Visual Mental Imagery Battery, CVMIB). Our results show that all mental imagery processes with the exception of the maintenance are affected by ageing, suggesting that other deficits, such as working memory deficits, could account for this effect. However, the analysis of the transformation process, investigated in terms of mental rotation and mental folding skills, shows a steeper decline in mental rotation, suggesting that age could affect rigid transformations of objects and spare non-rigid transformations. Our study also adds to previous ones in showing gender differences favoring men across the lifespan in the transformation process, and, interestingly, it shows a steeper decline in men than in women in inspecting mental images, which could partially account for the mixed results about the effect of ageing on this specific process. We also discuss the possibility to introduce the CVMIB in clinical assessment in the context of theoretical models of mental imagery.

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The representation of serial position in sequences is an important topic in a variety of cognitive areas including the domains of language, memory, and motor control. In the neuropsychological literature, serial position data have often been normalized across different lengths, and an improved procedure for this has recently been reported by Machtynger and Shallice (2009). Effects of length and a U-shaped normalized serial position curve have been criteria for identifying working memory deficits. We present simulations and analyses to illustrate some of the issues that arise when relating serial position data to specific theories. We show that critical distinctions are often difficult to make based on normalized data. We suggest that curves for different lengths are best presented in their raw form and that binomial regression can be used to answer specific questions about the effects of length, position, and linear or nonlinear shape that are critical to making theoretical distinctions. © 2010 Psychology Press.

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The insomnia disorder is defined as a difficulty initiating or maintaining sleep or waking up earlier than expected unable to return to sleep, followed by a feeling of nonrestorative and poor quality sleep, present for at least three months, with consequences on daytime functioning. Studies have shown that insomnia affects cognitive function, especially executive functions. However, researches that sought to investigate the relationship between primary insomnia and executive functioning were quite inconsistent from a methodological point of view, especially in regard to the variability of the used methods, the heterogeneity of diagnostic criteria for insomnia and the control of sleep altering drugs. In this sense, the present study aimed to investigate the relationship between insomnia and executive functions in adults. The participants were 29 people, from both genders, aged 20-55 years old. Participants were divided into three groups, one composed of 10 people with primary insomnia who used sleep medication (GIM), nine people with primary insomnia who did not use medication (GInM) and 10 healthy people who composed the control group (CG). The research was conducted in two stages. The first one involved a diagnostic evaluation for insomnia disorder through a clinical interview and the application of the following protocols: the Athens Insomnia Scale, the Insomnia Severity Index, Sleep Journal (for 14 days), Pittsburgh Sleep Quality Index (PSQI), the Stanford Sleepiness Test, depression and anxiety Beck inventories, and Lipp’s Iventory of stress symptoms for adults. After this stage, the evaluation of executive functions was performed by applying a battery of neuropsychological tests composed by the following tests: Wisconsin, Stoop Test, Colored trails Test, the Tower of London Test, Iowa Gambling Task (IGT) and WAIS III subtest digit span, which measured selective attention, inhibitory control, cognitive flexibility, planning, problem solving, decision making and working memory, respectively. The results showed that insomniacs (GIM and GInM) showed higher sleep latency, shorter sleep duration and lower sleep efficiency compared to the CG. In regard to the performance in executive functions, no statistically significant difference between groups was observed in the evaluated modalities. However, the data show evidence that, compared to GInM and GC, the performance of GIM was lower on tasks that required quick responses and changes in attention focus. On the other hand, GInM, when compared to GIM and GC, showed a better performance on tasks involving cognitive flexibility. Furthermore, impaired sleep measures were correlated with the worst performance of insomniacs in all components evaluated. In conclusion, people with the insomnia disorder showed a performance similar to healthy people’s in components of the executive functioning. Thus, one can infer that there is a relationship between primary insomnia and executive functions in adults.

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The time perception is critical for environmental adaptation in humans and other species. The temporal processing, has evolved through different neural systems, each responsible for processing different time scales. Among the most studied scales is that spans the arrangement of seconds to minutes. Evidence suggests that the dorsolateral prefrontal (DLPFC) cortex has relationship with the time perception scale of seconds. However, it is unclear whether the deficit of time perception in patients with brain injuries or even "reversible lesions" caused by transcranial magnetic stimulation (TMS) in this region, whether by disruption of other cognitive processes (such as attention and working memory) or the time perception itself. Studies also link the region of DLPFC in emotional regulation and specifically the judgment and emotional anticipation. Given this, our objective was to study the role of the dorsolateral prefrontal cortex in the time perception intervals of active and emotionally neutral stimuli, from the effects of cortical modulation by transcranial direct current stimulation (tDCS), through the cortical excitation (anodic current), inhibition (cathode current) and control (sham) using the ranges of 4 and 8 seconds. Our results showed that there is an underestimation when the picture was presented by 8 seconds, with the anodic current in the right DLPFC, there is an underestimation and with cathodic current in the left DLPFC, there is an overestimation of the time reproduction with neutral ones. The cathodic current over the left DLPFC leads to an inverse effect of neutral ones, an underestimation of time with negative pictures. Positive or negative pictures improved estimates for 8 second and positive pictures inhibited the effect of tDCS in DLPFC in estimating time to 4 seconds. With this work, we conclude that the DLPFC plays a key role in the o time perception and largely corresponds to the stages of memory and decision on the internal clock model. The left hemisphere participates in the perception of time in both active and emotionally neutral contexts, and we can conclude that the ETCC and an effective method to study the cortical functions in the time perception in terms of cause and effect.

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Reading and writing are essential rights, which involve individual and social aspects; in addition, these skills are important when it comes to socio economic and political development, critical thinking and an active participation in society (UNESCO 2005). From a neurobiological standpoint, our brain is not prepared for reading, and this practice must be deliberately acquired via instructional guidance (DEHAENE 2009). However, reading disorders and deficits within executive functions, such as low working memory capacity, can make reading arduous. The aim of this study is to investigate the development of reading skills within 45 third grade students from public schools in the city of Natal – RN and its connection to working memory capacity, through information gathered from the Provinha Brasil, data generated from working memory tasks (Portuguese version of AWMA - Automated Working Memory Assessment) and fluid intelligence measures RAVEN. Based on this main objective, we attempted to answer the following research questions: (a) What are the correlations between working memory and reading scores?; (b) What characterizes the relationship between working memory capacity and the risk of reading disabilities amongst the participants in this study?; Following a quantitative research methodology, the Provinhas Brasil from 3rd grade students belonging to the six public schools members of Project ACERTA - Avaliação de Crianças em Risco de Transtornos de Aprendizagem (CAPES/OBEDUC)- were analyzed and compared to the scores from the working memory tests and the fluid intelligence ones. Results indicate that reading skills within children at risk of reading disabilities are directly linked to working memory capacity, especially with regards to the phonological component. It is also evident that the participants with less working memory capacity show more difficulties in the reading abilities that demand interpretation skills. Thus, we intend to contribute to the discussion regarding the diagnosis of reading disabilities and possible intervention strategies.

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Reading and writing are essential rights, which involve individual and social aspects; in addition, these skills are important when it comes to socio economic and political development, critical thinking and an active participation in society (UNESCO 2005). From a neurobiological standpoint, our brain is not prepared for reading, and this practice must be deliberately acquired via instructional guidance (DEHAENE 2009). However, reading disorders and deficits within executive functions, such as low working memory capacity, can make reading arduous. The aim of this study is to investigate the development of reading skills within 45 third grade students from public schools in the city of Natal – RN and its connection to working memory capacity, through information gathered from the Provinha Brasil, data generated from working memory tasks (Portuguese version of AWMA - Automated Working Memory Assessment) and fluid intelligence measures RAVEN. Based on this main objective, we attempted to answer the following research questions: (a) What are the correlations between working memory and reading scores?; (b) What characterizes the relationship between working memory capacity and the risk of reading disabilities amongst the participants in this study?; Following a quantitative research methodology, the Provinhas Brasil from 3rd grade students belonging to the six public schools members of Project ACERTA - Avaliação de Crianças em Risco de Transtornos de Aprendizagem (CAPES/OBEDUC)- were analyzed and compared to the scores from the working memory tests and the fluid intelligence ones. Results indicate that reading skills within children at risk of reading disabilities are directly linked to working memory capacity, especially with regards to the phonological component. It is also evident that the participants with less working memory capacity show more difficulties in the reading abilities that demand interpretation skills. Thus, we intend to contribute to the discussion regarding the diagnosis of reading disabilities and possible intervention strategies.

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Peer reviewed

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Attention-deficit hyperactivity disorder (ADHD) is the most prevalent and impairing neurodevelopmental disorder, with worldwide estimates of 5.29%. ADHD is clinically characterized by hyperactivity-impulsivity and inattention, with neuropsychological deficits in executive functions, attention, working memory and inhibition. These cognitive processes rely on prefrontal cortex function; cognitive training programs enhance performance of ADHD participants supporting the idea of neuronal plasticity. Here we propose the development of an on-line puzzle game based assessment and training tool in which participants must deduce the ‘winning symbol’ out of N distracters. To increase ecological validity of assessments strategically triggered Twitter/Facebook notifications will challenge the ability to ignore distracters. In the UK, significant cost for the disorder on health, social and education services, stand at £23m a year. Thus the potential impact of neuropsychological assessment and training to improve our understanding of the pathophysiology of ADHD, and hence our treatment interventions and patient outcomes, cannot be overstated.

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Pour être performant au plus haut niveau, les athlètes doivent posséder une capacité perceptivo-cognitive supérieure à la moyenne. Cette faculté, reflétée sur le terrain par la vision et l’intelligence de jeu des sportifs, permet d’extraire l’information clé de la scène visuelle. La science du sport a depuis longtemps observé l’expertise perceptivo-cognitive au sein de l’environnement sportif propre aux athlètes. Récemment, des études ont rapporté que l’expertise pouvait également se refléter hors de ce contexte, lors d’activités du quotidien par exemple. De plus, les récentes théories entourant la capacité plastique du cerveau ont amené les chercheurs à développer des outils pour entraîner les capacités perceptivo-cognitives des athlètes afin de les rendre plus performants sur le terrain. Ces méthodes sont la plupart du temps contextuelles à la discipline visée. Cependant, un nouvel outil d’entraînement perceptivo-cognitif, nommé 3-Dimensional Multiple Object Tracking (3D-MOT) et dénué de contexte sportif, a récemment vu le jour et a fait l’objet de nos recherches. Un de nos objectifs visait à mettre en évidence l’expertise perceptivo-cognitive spécifique et non-spécifique chez des athlètes lors d’une même étude. Nous avons évalué la perception du mouvement biologique chez des joueurs de soccer et des non-athlètes dans une salle de réalité virtuelle. Les sportifs étaient systématiquement plus performants en termes d’efficacité et de temps de réaction que les novices pour discriminer la direction du mouvement biologique lors d’un exercice spécifique de soccer (tir) mais également lors d’une action issue du quotidien (marche). Ces résultats signifient que les athlètes possèdent une meilleure capacité à percevoir les mouvements biologiques humains effectués par les autres. La pratique du soccer semble donc conférer un avantage fondamental qui va au-delà des fonctions spécifiques à la pratique d’un sport. Ces découvertes sont à mettre en parallèle avec la performance exceptionnelle des athlètes dans le traitement de scènes visuelles dynamiques et également dénuées de contexte sportif. Des joueurs de soccer ont surpassé des novices dans le test de 3D-MOT qui consiste à suivre des cibles en mouvement et stimule les capacités perceptivo-cognitives. Leur vitesse de suivi visuel ainsi que leur faculté d’apprentissage étaient supérieures. Ces résultats confirmaient des données obtenues précédemment chez des sportifs. Le 3D-MOT est un test de poursuite attentionnelle qui stimule le traitement actif de l’information visuelle dynamique. En particulier, l’attention sélective, dynamique et soutenue ainsi que la mémoire de travail. Cet outil peut être utilisé pour entraîner les fonctions perceptivo-cognitives des athlètes. Des joueurs de soccer entraînés au 3D-MOT durant 30 sessions ont montré une amélioration de la prise de décision dans les passes de 15% sur le terrain comparés à des joueurs de groupes contrôles. Ces données démontrent pour la première fois un transfert perceptivo-cognitif du laboratoire au terrain suivant un entraînement perceptivo-cognitif non-contextuel au sport de l’athlète ciblé. Nos recherches aident à comprendre l’expertise des athlètes par l’approche spécifique et non-spécifique et présentent également les outils d’entraînements perceptivo-cognitifs, en particulier le 3D-MOT, pour améliorer la performance dans le sport de haut-niveau.

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For over 50 years, the Satisfaction of Search effect, and more recently known as the Subsequent Search Miss (SSM) effect, has plagued the field of radiology. Defined as a decrease in additional target accuracy after detecting a prior target in a visual search, SSM errors are known to underlie both real-world search errors (e.g., a radiologist is more likely to miss a tumor if a different tumor was previously detected) and more simplified, lab-based search errors (e.g., an observer is more likely to miss a target ‘T’ if a different target ‘T’ was previously detected). Unfortunately, little was known about this phenomenon’s cognitive underpinnings and SSM errors have proven difficult to eliminate. However, more recently, experimental research has provided evidence for three different theories of SSM errors: the Satisfaction account, the Perceptual Set account, and the Resource Depletion account. A series of studies examined performance in a multiple-target visual search and aimed to provide support for the Resource Depletion account—a first target consumes cognitive resources leaving less available to process additional targets.

To assess a potential mechanism underlying SSM errors, eye movements were recorded in a multiple-target visual search and were used to explore whether a first target may result in an immediate decrease in second-target accuracy, which is known as an attentional blink. To determine whether other known attentional distractions amplified the effects of finding a first target has on second-target detection, distractors within the immediate vicinity of the targets (i.e., clutter) were measured and compared to accuracy for a second target. To better understand which characteristics of attention were impacted by detecting a first target, individual differences within four characteristics of attention were compared to second-target misses in a multiple-target visual search.

The results demonstrated that an attentional blink underlies SSM errors with a decrease in second-target accuracy from 135ms-405ms after detection or re-fixating a first target. The effects of clutter were exacerbated after finding a first target causing a greater decrease in second-target accuracy as clutter increased around a second-target. The attentional characteristics of modulation and vigilance were correlated with second- target misses and suggest that worse attentional modulation and vigilance are predictive of more second-target misses. Taken together, these result are used as the foundation to support a new theory of SSM errors, the Flux Capacitor theory. The Flux Capacitor theory predicts that once a target is found, it is maintained as an attentional template in working memory, which consumes attentional resources that could otherwise be used to detect additional targets. This theory not only proposes why attentional resources are consumed by a first target, but encompasses the research in support of all three SSM theories in an effort to establish a grand, unified theory of SSM errors.

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Background: It is well documented that children with Specific Language Impairment (SLI) experience significant grammatical deficits. While much of the focus in the past has been on their morphosyntactic difficulties, less is known about their acquisition of complex syntactic structures such as relative clauses. The role of memory in language performance has also become increasingly prominent in the literature. Aims: This study aims to investigate the control of an important complex syntactic structure, the relative clause, by school age children with SLI in Ireland, using a newly devised sentence recall task. It also aims to explore the role of verbal and short-termworking memory in the performance of children with SLI on the sentence recall task, using a standardized battery of tests based on Baddeley’s model of working memory. Methods and Procedures: Thirty two children with SLI, thirty two age matched typically developing children (AM-TD) between the ages of 6 and 7,11 years and twenty younger typically developing (YTD) children between 4,7 and 5 years, completed the task. The sentence recall (SR) task included 52 complex sentences and 17 fillers. It included relative clauses that are used in natural discourse and that reflect a developmental hierarchy. The relative clauses were also controlled for length and varied in syntactic complexity, representing the full range of syntactic roles. There were seven different relative clause types attached to either the predicate nominal of a copular clause (Pn), or to the direct object of a transitive clause (Do). Responses were recorded, transcribed and entered into a database for analysis. TheWorkingMemory Test Battery for children (WMTB-C—Pickering & Gathercole, 2001) was administered in order to explore the role of short-term memory and working memory on the children’s performance on the SR task. Outcomes and Results: The children with SLI showed significantly greater difficulty than the AM-TD group and the YTD group. With the exception of the genitive subject clauses, the children with SLI scored significantly higher on all sentences containing a Pn main clause than those containing a transitive main clause. Analysis of error types revealed the frequent production of a different type of relative clause than that presented in the task—with a strong word order preference in the NVN direction indicated for the children with SLI. The SR performance for the children with SLI was most highly correlated with expressive language skills and digit recall. Conclusions and Implications: Children with SLI have significantly greater difficulty with relative clauses than YTD children who are on average two years younger—relative clauses are a delay within a delay. Unlike the YTD children they show a tendency to simplify relative clauses in the noun verb noun (NVN) direction. They show a developmental hierarchy in their production of relative clause constructions and are highly influenced by the frequency distribution of the relative clauses in the ambient language.

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Duchenne muscular dystrophy (DMD) is an X chromosome-linked disease characterized by progressive physical disability, immobility, and premature death in affected boys. Underlying the devastating symptoms of DMD is the loss of dystrophin, a structural protein that connects the extracellular matrix to the cell cytoskeleton and provides protection against contraction-induced damage in muscle cells, leading to chronic peripheral inflammation. However, dystrophin is also expressed in neurons within specific brain regions, including the hippocampus, a structure associated with learning and memory formation. Linked to this, a subset of boys with DMD exhibit nonprogressing cognitive dysfunction, with deficits in verbal, short-term, and working memory. Furthermore, in the genetically comparable dystrophin-deficient mdx mouse model of DMD, some, but not all, types of learning and memory are deficient, and specific deficits in synaptogenesis and channel clustering at synapses has been noted. Little consideration has been devoted to the cognitive deficits associated with DMD compared with the research conducted into the peripheral effects of dystrophin deficiency. Therefore, this review focuses on what is known about the role of full-length dystrophin (Dp427) in hippocampal neurons. The importance of dystrophin in learning and memory is assessed, and the potential importance that inflammatory mediators, which are chronically elevated in dystrophinopathies, may have on hippocampal function is also evaluated.

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Currently there is no consensus as to the specific cognitive impairments that characterize mathematical disabilities (MD) or specific subtypes such as an arithmetic disability (AD). The present study sought to address this concern by examining cognitive processes that might undergird AD in children. The present study utilized archival data to conduct two investigations. The first investigation examined the executive functioning and working memory of children with AD. An age-matched achievement-matched design was employed to explore whether children with AD exhibit developmental lags or deficits in these cognitive domains. While children with AD did not exhibit impairments in verbal working memory or colour word inhibition, they did demonstrate impairments in shifting attention, visual-spatial working memory, and quantity inhibition. As children with AD did not perform more poorly than their younger achievement-matched peers on any of these tasks, impairments in specific areas of executive functioning and working memory appeared to reflect a developmental lag rather than a cognitive deficit. The second study examined the phonological processing performance of children with AD compared to children with comorbid disabilities in arithmetic and word recognition (AD/WRD) and to typically achieving (TA) children. Results indicated that, while children with AD did demonstrate impairments on all isolated naming speed tasks, trail making digits, and memory for digits, they did not demonstrate impairments on measures of phonological awareness, nonword repetition, serial processing speed, or serial naming speed. In contrast, children with AD/WRD demonstrated impairments on measures of phonological awareness, phonological short-term memory, isolated naming speed, serial processing speed, and the alphabet a-z task. Overall, results suggested that phonological processing impairments are more prominent in children with a WRD than children with an AD. Together, these studies further our understanding of the nature of the cognitive processes that underlie AD by focusing upon rarely used methods (i.e., age-matched achievement-matched design) and under-examined cognitive domains (i.e., phonological processing).

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Scientific reading research has produced substantial evidence linking specific reading components to a range of constructs including phonological awareness (PA), morphological awareness, orthographic processing (OP), rapid automatized naming, working memory and vocabulary. There is a paucity of research on Arabic, although 420 million people around the world (Gordon, 2005) speak Arabic. As a Semitic language, Arabic differs in many ways from Indo-European languages. Over the past three decades, literacy research has begun to elucidate the importance of morphological awareness (MA) in reading. Morphology is a salient aspect of Arabic word structure. This study was designed to (a) examine the dimensions underlying MA in Arabic; (b) determine how well MA predicts reading; (c) investigate the role of the standard predictors in different reading outcomes; and (d) investigate the construct of reading in Arabic. This study was undertaken in two phases. In Phase I, 10 MA measures and two reading measures were developed, and tested in a sample of 102 Grade 3 Arabic-speaking children. Factor analysis of the 10 MA tasks yielded one predominant factor supporting the construct validity of MA in Arabic. Hierarchical regression analyses, controlling for age and gender, indicated that the MA factor solution accounted for 41– 43% of the variance in reading. In Phase II, the widely studied predictor measures were developed for PA and OP in addition to one additional measure of MA (root awareness), and three reading measures In Phase II, all measures were administered to another sample of 201 Grade 3 Arabic-speaking children. The construct of reading in Arabic was examined using factor analysis. The joint and unique effects of all standard predictors were examined using different sets of hierarchical regression analyses. Results of Phase II showed that: (a) all five reading measures loaded on one factor; (b) MA consistently accounted for unique variance in reading, particularly in comprehension, above and beyond the standard predictors; and (c) the standard predictors had differential contributions. These findings underscore the contribution of MA to all components of Arabic reading. The need for more emphasis on including morphology in Arabic reading instruction and assessment is discussed.

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This paper focuses on two basic issues: the anxiety-generating nature of the interpreting task and the relevance of interpreter trainees’ academic self-concept. The first has already been acknowledged, although not extensively researched, in several papers, and the second has only been mentioned briefly in interpreting literature. This study seeks to examine the relationship between the anxiety and academic self-concept constructs among interpreter trainees. An adapted version of the Foreign Language Anxiety Scale (Horwitz et al., 1986), the Academic Autoconcept Scale (Schmidt, Messoulam & Molina, 2008) and a background information questionnaire were used to collect data. Students’ t-Test analysis results indicated that female students reported experiencing significantly higher levels of anxiety than male students. No significant gender difference in self-concept levels was found. Correlation analysis results suggested, on the one hand, that younger would-be interpreters suffered from higher anxiety levels and students with higher marks tended to have lower anxiety levels; and, on the other hand, that younger students had lower self-concept levels and higher-ability students held higher self-concept levels. In addition, the results revealed that students with higher anxiety levels tended to have lower self-concept levels. Based on these findings, recommendations for interpreting pedagogy are discussed.