940 resultados para cognitive control


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Objectives. Emotional dysregulation in bipolar disorder is thought to arise from dysfunction within prefrontal cortical regions involved in cognitive control coupled with increased or aberrant activation within regions engaged in emotional processing. The aim of this study was to determine the common and distinct patterns of functional brain abnormalities during reward and working memory processing in patients with bipolar disorder. Methods. Participants were 36 euthymic bipolar disorder patients and 37 healthy comparison subjects matched for age, sex and IQ. Functional magnetic resonance imaging (fMRI) was conducted during the Iowa Gambling Task (IGT) and the n-back working memory task. Results. During both tasks, patients with bipolar disorder demonstrated a pattern of inefficient engagement within the ventral frontopolar prefrontal cortex with evidence of segregation along the medial-lateral dimension for reward and working memory processing, respectively. Moreover, patients also showed greater activation in the anterior cingulate cortex during the Iowa Gambling Task and in the insula during the n-back task. Conclusions. Our data implicate ventral frontopolar dysfunction as a core abnormality underpinning bipolar disorder and confirm that overactivation in regions involved in emotional arousal is present even in tasks that do not typically engage emotional systems. © 2012 Informa Healthcare.

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Involuntary episodic memories are memories that come into consciousness without preceding retrieval effort. These memories are commonplace and are relevant to multiple mental disorders. However, they are vastly understudied. We use a novel paradigm to elicit involuntary memories in the laboratory so that we can study their neural basis. In session one, an encoding session, sounds are presented with picture pairs or alone. In session two, in the scanner, sounds-picture pairs and unpaired sounds are reencoded. Immediately following, participants are split into two groups: a voluntary and an involuntary group. Both groups perform a sound localization task in which they hear the sounds and indicate the side from which they are coming. The voluntary group additionally tries to remember the pictures that were paired with the sounds. Looking at neural activity, we find a main effect of condition (paired vs. unpaired sounds) showing similar activity in both groups for voluntary and involuntary memories in regions typically associated with retrieval. There is also a main effect of group (voluntary vs. involuntary) in the dorsolateral prefrontal cortex, a region typically associated with cognitive control. Turning to connectivity similarities and differences between groups again, there is a main effect of condition showing paired > unpaired sounds are associated with a recollection network. In addition, three group differences were found: (1) increased connectivity between the pulvinar nucleus of the thalamus and the recollection network for the voluntary group, (2) a higher association between the voluntary group and a network that includes regions typically found in frontoparietal and cingulo-opercular networks, and (3) shorter path length for about half of the nodes in these networks for the voluntary group. Finally, we use the same paradigm to compare involuntary memories in people with posttraumatic stress disorder (PTSD) to trauma-controls. This study also included the addition of emotional pictures. There were two main findings. (1) A similar pattern of activity was found for paired > unpaired sounds for both groups but this activity was delayed in the PTSD group. (2) A similar pattern of activity was found for high > low emotion stimuli but it occurred early in the PTSD group compared to the control group. Our results suggest that involuntary and voluntary memories share the same neural representation but that voluntary memories are associated with additional cognitive control processes. They also suggest that disorders associated with cognitive deficits, like PTSD, can affect the processing of involuntary memories.

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Genetic and environmental factors interact to influence vulnerability for internalizing psychopathology, including Major Depressive Disorder (MDD). The mechanisms that account for how environmental stress can alter biological systems are not yet well understood yet are critical to develop more accurate models of vulnerability and targeted interventions. Epigenetic influences, and more specifically, DNA methylation, may provide a mechanism by which stress could program gene expression, thereby altering key systems implicated in depression, such as frontal-limbic circuitry and its critical role in emotion regulation. This thesis investigated the role of environmental factors from infancy and throughout the lifespan affecting the serotonergic (5-HT) system in the vulnerability to and treatment of depression and anxiety and potential underlying DNA methylation processes. First, we investigated the contributions of additive genetic vs. environmental factors on an early trait phenotype for depression (negative emotionality) in infants and their stability over time in the first 2 years of life. We provided evidence of the substantial contributions of both genetic and shared environmental factors to this trait, as well as genetically- and environmentally- mediated stability and innovation. Second, we studied how childhood environmental stress is associated with peripheral DNA methylation of the serotonin transporter gene, SLC6A4, as well as long-term trajectories of internalizing behaviours. There was a relationship between childhood psychosocial adversity and SLC6A4 methylation in males, as well as between SLC6A4 methylation and internalizing trajectory in both sexes. Third, we investigated changes in emotion processing and epigenetic modification of the SLC6A4 gene in depressed adolescents before and after Mindfulness-Based Cognitive Therapy (MBCT). The alterations from pre- to post-treatment in connectivity between the ACC and other network regions and SLC6A4 methylation suggested that MBCT may work to optimize the connectivity of brain networks involved in cognitive control of emotion as well as also normalize the relationship between SLC6A4 methylation and activation patterns in frontal-limbic circuitry. Our results from these three studies strengthen the theory that environmental influences are critical in establishing early vulnerability factors for MDD, driving epigenetic processes, and altering brain processes as an individual undergoes treatment, or experiences relapse.

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Adolescence is characterized by dramatic hormonal, physical, and psychological changes, and is a period of risk for affective and anxiety disorders. Pubertal development during adolescence plays a major role in the emergence of these disorders, particularly among girls. Thus, it is critical to identify early biomarkers of risk. One potential biomarker, the error-related negativity (ERN), is an event-related potential following an erroneous response. Individuals with an anxiety disorder demonstrate a greater ERN than healthy comparisons, an association which is stronger in adolescence, suggesting that pubertal development may play a role in the ERN as a predictor of anxiety. One form of anxiety often observed in adolescence, particularly among girls, is social anxiety, which is defined as anxiety elicited by social-evaluative contexts. In adults, enhancements of the ERN in social-evaluative contexts is positively related to social anxiety symptoms, suggesting that the ERN in social contexts may serve as a biomarker for social anxiety. This dissertation examined the ERN in and its relation with puberty and social anxiety among 76 adolescent girls. Adolescent girls completed a flanker task in two different

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Thesis (Ph.D, Psychology) -- Queen's University, 2016-10-04 17:37:07.888

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BACKGROUND: Despite the health benefits of regular physical activity, most children are insufficiently active. Schools are ideally placed to promote physical activity; however, many do not provide children with sufficient in-school activity or ensure they have the skills and motivation to be active beyond the school setting. The aim of this project is to modify, scale up and evaluate the effectiveness of an intervention previously shown to be efficacious in improving children's physical activity, fundamental movement skills and cardiorespiratory fitness. The 'Internet-based Professional Learning to help teachers support Activity in Youth' (iPLAY) study will focus largely on online delivery to enhance translational capacity.

METHODS/DESIGN: The intervention will be implemented at school and teacher levels, and will include six components: (i) quality physical education and school sport, (ii) classroom movement breaks, (iii) physically active homework, (iv) active playgrounds, (v) community physical activity links and (vi) parent/caregiver engagement. Experienced physical education teachers will deliver professional learning workshops and follow-up, individualized mentoring to primary teachers (i.e., Kindergarten - Year 6). These activities will be supported by online learning and resources. Teachers will then deliver the iPLAY intervention components in their schools. We will evaluate iPLAY in two complementary studies in primary schools across New South Wales (NSW), Australia. A cluster randomized controlled trial (RCT), involving a representative sample of 20 schools within NSW (1:1 allocation at the school level to intervention and attention control conditions), will assess effectiveness and cost-effectiveness at 12 and 24 months. Students' cardiorespiratory fitness will be the primary outcome in this trial. Key secondary outcomes will include students' moderate-to-vigorous physical activity (via accelerometers), fundamental movement skill proficiency, enjoyment of physical education and sport, cognitive control, performance on standardized tests of numeracy and literacy, and cost-effectiveness. A scale-up implementation study guided by the RE-AIM framework will evaluate the reach, effectiveness, adoption, implementation, and maintenance of the intervention when delivered in 160 primary schools in urban and regional areas of NSW.

DISCUSSION: This project will provide the evidence and a framework for government to guide physical activity promotion throughout NSW primary schools and a potential model for adoption in other states and countries.

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The topic of this thesis is impulsivity. The meaning and measurement of impulse control is explored, with a particular focus on forensic settings. Impulsivity is central to many areas of psychology; it is one of the most common diagnostic criteria of mental disorders and is fundamental to the understanding of forensic personalities. Despite this widespread importance there is little agreement as to the definition or structure of impulsivity, and its measurement is fraught with difficulty owing to a reliance on self-report methods. This research aims to address this problem by investigating the viability of using simple computerised cognitive performance tasks as complementary components of a multi-method assessment strategy for impulse control. Ultimately, the usefulness of this measurement strategy for a forensic sample is assessed. Impulsivity is found to be a multifaceted construct comprised of a constellation of distinct sub-dimensions. Computerised cognitive performance tasks are valid and reliable measures that can assess impulsivity at a neuronal level. Self-report and performance task methods assess distinct components of impulse control and, for the optimal assessment of impulse control, a multi-method battery of self-report and performance task measures is advocated. Such a battery is shown to have demonstrated utility in a forensic sample, and recommendations for forensic assessment in the Irish context are discussed.

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Objective: Cognitive-behavioural therapy (CBT) has proved effective in treating delusions, both in schizophrenia and delusional disorder (DD). Clinical trials of DD have mostly compared CBT with either treatment as usual, no treatment, or a wait-list control. This current study aimed to assess patients with DD who received CBT, compared with an attention placebo control (APC) group. Method: Twenty-four individuals with DD were randomly allocated into either CBT or APC groups for a 24-week treatment period. Patients were diagnosed on the basis of structured clinical interviews for mental disorders and the Maudsley Assessment of Delusion Schedule (MADS). Results: Completers in both groups (n = 11 for CBT; n = 6 for APC) showed clinical improvement on the MADS dimensions of Strength of Conviction, Insight, Preoccupation, Systematization, Affect Relating to Belief, Belief Maintenance Factors, and Idiosyncrasy of Belief. Conclusion: When compared with APC, CBT produced more impact on the MADS dimensions for Affect Relating to Belief, Strength of Conviction, and Positive Actions on Beliefs.

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In recent years, various efforts have been made in air traffic control (ATC) to maintain traffic safety and efficiency in the face of increasing air traffic demands. ATC is a complex process that depends to a large degree on human capabilities, and so understanding how controllers carry out their tasks is an important issue in the design and development of ATC systems. In particular, the human factor is considered to be a serious problem in ATC safety and has been identified as a causal factor in both major and minor incidents. There is, therefore, a need to analyse the mechanisms by which errors occur due to complex factors and to develop systems that can deal with these errors. From the cognitive process perspective, it is essential that system developers have an understanding of the more complex working processes that involve the cooperative work of multiple controllers. Distributed cognition is a methodological framework for analysing cognitive processes that span multiple actors mediated by technology. In this research, we attempt to analyse and model interactions that take place in en route ATC systems based on distributed cognition. We examine the functional problems in an ATC system from a human factors perspective, and conclude by identifying certain measures by which to address these problems. This research focuses on the analysis of air traffic controllers' tasks for en route ATC and modelling controllers' cognitive processes.

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Awareness of emerging situations in a dynamic operational environment of a robotic assistive device is an essential capability of such a cognitive system, based on its effective and efficient assessment of the prevailing situation. This allows the system to interact with the environment in a sensible (semi)autonomous / pro-active manner without the need for frequent interventions from a supervisor. In this paper, we report a novel generic Situation Assessment Architecture for robotic systems directly assisting humans as developed in the CORBYS project. This paper presents the overall architecture for situation assessment and its application in proof-of-concept Demonstrators as developed and validated within the CORBYS project. These include a robotic human follower and a mobile gait rehabilitation robotic system. We present an overview of the structure and functionality of the Situation Assessment Architecture for robotic systems with results and observations as collected from initial validation on the two CORBYS Demonstrators.

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The aim of the Youth Depression Alleviation-Combined Treatment (YoDA-C) study is to determine whether antidepressant medication should be started as a first-line treatment for youth depression delivered concurrently with psychotherapy. Doubts about the use of medication have been raised by meta-analyses in which the efficacy and safety of antidepressants in young people have been questioned, and subsequent treatment guidelines for youth depression have provided only qualified support.

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Objective To verify the effects of a systematized multimodal exercise intervention program on frontal cognitive function, postural control, and functional capacity components of individuals with Alzheimer's disease (AD).DesignNonrandomized controlled trial with pre- and posttraining tests in a training group and a control group.SettingKinesiotherapy program for seniors with AD, SAo Paulo State University.ParticipantsConvenience sample of older adults with AD (n=30) were assigned to a training (n=14; aged 78.67.1) and a control (n=16; aged 77.06.3) group.InterventionThe intervention program was structured with the aim of simultaneously promoting better balance and frontal cognitive capacity. The participants attended a 1-hour session three times a week for 16weeks, whereas the control group did not participate in any activity during the same period.MeasurementsFrontal cognitive function was evaluated using the Montreal Cognitive Assessment, the Clock Drawing Test, the Frontal Assessment Battery, and the Symbol Search Subtest. Postural control (center of pressure area) was analyzed under four dual-task conditions. Functional capacity components were analyzed using the Timed Up and Go Test, the 30-second sit-to-stand test, the sit-and-reach test, and the Berg Functional Balance Scale.ResultsIntervention group participants showed a significant increase in frontal cognitive function (P<.001, partial (2)=0.838), with less body sway (P=.04, partial (2)=0.04) during the dual tasks, and greater functional capacity (P=.001, partial (2)=0.676) after the 16-week period.ConclusionIntervention participants performed better on dual-task activities and had better postural balance and greater functional capacity than controls.