90 research outputs found

    Identifying the functional architecture underlying multiple representations in visual working memory

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    ABSTRACT This thesis aimed to investigate how visual working memory takes advantage of long-term knowledge in order to allow semantic elaboration in the form of chunking and the role of the central executive in this process. Two leading theoretical frameworks of working memory which both emphasise the role of long-term memory are discussed. One of which views working memory as consisting of multiple discrete, modality specific subsystems (Baddeley, 2000) and one which views working memory as an activated subset of long term memory (Cowan, 2005). Both of these models propose the integration of short- and long-term representations to be attentionally demanding. To investigate this assumption, two forms of visual matrix pattern were generated; a high semantic set which lends itself to long-term memory support and a low semantic set which does so to a lesser extent. The initial block of empirical work aimed to establish the characteristics of the patterns sets. Superiority for the high semantic patterns was observed in terms of greater stability across increasing maintenance intervals. The benefit of increased presentation time was also shown to be greater for the high semantic pattern set indicating the importance of time in the semantic elaboration process. A second block of studies was then conducted to identify the implications of the two patterns sets for the functional architecture of working memory. In a secondary interference paradigm the pattern sets were shown to be differentially dependent on visual and verbal interference with low semantic patterns negatively affected by visual and not verbal interference and the opposite pattern observed for high semantic patterns. The use of executive and attentional interference paradigms demonstrated two levels of binding. Firstly, when attentional resources were continually captured by a secondary task, a degree of chunking was observed for both pattern sets, this is discussed in terms of passive binding on the basis of long-term knowledge in the absence of executive resources. In the absence of interference, effortful elaboration of the pattern sets is observed and this is greater for the high semantic patterns. This is discussed in terms of active binding with the involvement of executive resources. These findings are then discussed in terms of both the Cowan (2005) and Baddeley (2000) models and recent observations made by Baddeley et al (in press) to support a modification of the episodic buffer in Baddeley?s model to allow for both passive and active binding and how this leads to striking similarities between the two theoretical perspectives

    Retrieval and monitoring processes during visual working memory: An ERP study of the benefit of visual semantics

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    In this study we examined electrophysiological indices of episodic remembering whilst participants recalled novel shapes, with and without semantic content, within a visual working memory paradigm. The components of interest were the parietal episodic (PE; 400-800ms) and late posterior negativity (LPN; 500-900ms), as these have previously been identified as reliable markers of recollection and post retrieval monitoring, respectively. Fifteen young adults completed a visual matrix patterns task, assessing memory for low and high semantic visual representations. Matrices with either low semantic or high semantic content (containing familiar visual forms) were briefly presented to participants for study (1500ms), followed by a retention interval (6000ms) and finally a same/different recognition phase. The event-related potentials of interest were tracked from the onset of the recognition test stimuli. Analyses revealed equivalent amplitude for the earlier PE effect for the processing of both low and high semantic stimulus types. However, the LPN was more negative-going for the processing of the low semantic stimuli. These data are discussed in terms of relatively ‘pure’ retrieval of high semantic items, where support can readily be recruited from semantic memory. However, for the low semantic items additional executive resources, as indexed by the LPN, are recruited when memory monitoring and uncertainty exist in order to recall previously studied items more effectively

    New academics’ experiences of induction to teaching: an Activity Theory approach

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    In this article we present findings of a research project investigating the experiences of new academics in the process of becoming effective teachers, using an Activity Theory framework (Engestrom, 2001 ). The research was undertaken in a post-92 university that has shifted from teaching and professional development to prioritise a new emphasis on research. However, all academics have a dual responsibility for teaching and research. The project brought us together as education developers who were involved in the induction of academics into teaching across six departments. We shared a common aim in trying to understand the issues faced by new academics in their various disciplines and departments, in order to improve their induction experience and provide an enhanced CPD offer

    Identifying the functional architecture underlying multiple representations in visual working memory

    Get PDF
    This thesis aimed to investigate how visual working memory takes advantage of long-term knowledge in order to allow semantic elaboration in the form of chunking and the role of the central executive in this process. Two leading theoretical frameworks of working memory which both emphasise the role of long-term memory are discussed. One of which views working memory as consisting of multiple discrete, modality specific subsystems (Baddeley, 2000) and one which views working memory as an activated subset of long term memory (Cowan, 2005). Both of these models propose the integration of short- and long-term representations to be attentionally demanding. To investigate this assumption, two forms of visual matrix pattern were generated; a high semantic set which lends itself to long-term memory support and a low semantic set which does so to a lesser extent. The initial block of empirical work aimed to establish the characteristics of the patterns sets. Superiority for the high semantic patterns was observed in terms of greater stability across increasing maintenance intervals. The benefit of increased presentation time was also shown to be greater for the high semantic pattern set indicating the importance of time in the semantic elaboration process. A second block of studies was then conducted to identify the implications of the two patterns sets for the functional architecture of working memory. In a secondary interference paradigm the pattern sets were shown to be differentially dependent on visual and verbal interference with low semantic patterns negatively affected by visual and not verbal interference and the opposite pattern observed for high semantic patterns. The use of executive and attentional interference paradigms demonstrated two levels of binding. Firstly, when attentional resources were continually captured by a secondary task, a degree of chunking was observed for both pattern sets, this is discussed in terms of passive binding on the basis of long-term knowledge in the absence of executive resources. In the absence of interference, effortful elaboration of the pattern sets is observed and this is greater for the high semantic patterns. This is discussed in terms of active binding with the involvement of executive resources. These findings are then discussed in terms of both the Cowan (2005) and Baddeley (2000) models and recent observations made by Baddeley et al (in press) to support a modification of the episodic buffer in Baddeley's model to allow for both passive and active binding and how this leads to striking similarities between the two theoretical perspectives.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

    Do maternal concerns at delivery predict parenting stress during infancy?

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    Objective: In a previous study,we found that newmothers could andwould express concerns about their parenting, including concerns about maltreatment and poor care. In this study,we examine the utility of early maternal concerns for predicting parenting stress in the first year. Parenting stress is important because it has been shown to be related to maltreatment and poor parent-child relationships. Method: A sample of 246 mothers were interviewed shortly after delivery in a publicly funded hospital about their parenting concerns, and 93% were reinterviewed in their homes about their parenting when the infants were 6 to 12 months old. Standardized measures with demonstrated psychometric properties were employed, including a measure of parenting stress due to the demands of the parenting role, characteristics of the child that make him or her difficult to care for, and stress due to difficult interactions. Results: Multiple regression results indicate that both mothers concerns at delivery and sociodemographic variables are significant predictors of all three types of parenting stress in infancy. Maternal concerns were more powerful than sociodemographics in predicting stress related to the demands of parenting, while sociodemographics were more powerful for the prediction of stress related to difficult child characteristics and difficult mother-infant interaction. Conclusions: These findings suggest that knowledge of new mothers’ parenting concerns might be useful for predicting parenting problems, as well as for engaging mothers in and enhancing the effectiveness of parenting services

    Student Loneliness: The Role of Social Media Through Life Transitions

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    The move to university can be difficult for students- a transition often characterised by a risk of loneliness and poor mental health. Previous work highlights the important role social media can play in this transition. We report findings from a large-scale survey of 510 first year un-dergraduates across the UK, identifying factors that predict student loneliness, and exploring their social media use. Higher levels of social capital, induction satisfaction, and sense of community are significantly associated with lower levels of loneliness. Conversely, those reporting a more ‘liminal self’- the desire to edit and reinvent yourself online - experience greater loneliness- with an indirect relationship between online social information seeking and loneliness, through social capital. We surmise that being ‘true to yourself’ online is important when starting university, and that social media can be a useful tool in facilitating offline relationships and maintaining ties to old friends

    Food for Thought: the Efficiency of Glucose Metabolism Predicts the Self-generation of Temporally Distant Cognition

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    The generation of thought independent of environmental input occupies almost half of mental life and is important for skills such as creativity and planning. To understand how this ubiquitous cognitive process relates to the brain's ‘energy budget’, a cross-sectional study is carried out to examine how the capacity for mental time travel relates to the efficiency with which adults metabolize glucose, the brain’s primary source of fuel. On day 1 the ability of a group of 36 younger and 36 older individuals to metabolize glucose was assessed using the gold standard two-hour glucose tolerance test. Twenty-four hours later, the same group of participants returned to the laboratory to perform a non-demanding choice reaction time task during which experience sampling was used to assess the frequency with which they generated thoughts that were unrelated to the here and now. Analysis indicated that younger individuals who were the most efficient at metabolizing glucose exhibited mental time travel that spanned longer time periods. Given the importance of self-generated thought in daily life these results suggest that the capacity to mentally simulate events not present in the immediate environment is highly dependent on efficient glucose metabolis

    Selective inhibition of protein secretion by abrogating receptor–coat interactions during ER export

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    Protein secretion is an essential process that drives cell growth, movement, and commu-nication. Protein traffic within the secretory pathway occurs via transport intermediatesthat bud from one compartment and fuse with a downstream compartment to delivertheir contents. Here, we explore the possibility that protein secretion can be selectivelyinhibited by perturbing protein–protein interactions that drive capture into transportvesicles. Human proprotein convertase subtilisin/kexin type 9 (PCSK9) is a determi-nant of cholesterol metabolism whose secretion is mediated by a specific cargo adaptorprotein, SEC24A. We map a series of protein–protein interactions between PCSK9, itsendoplasmic reticulum (ER) export receptor SURF4, and SEC24A that mediate secre-tion of PCSK9. We show that the interaction between SURF4 and SEC24A can beinhibited by 4-phenylbutyrate (4-PBA), a small molecule that occludes a cargo-bindingdomain of SEC24. This inhibition reduces secretion of PCSK9 and additional SURF4clients that we identify by mass spectrometry, leaving other secreted cargoes unaffected.We propose that selective small-molecule inhibition of cargo recognition by SEC24 is apotential therapeutic intervention for atherosclerosis and other diseases that are modu-lated by secreted proteins

    Selective inhibition of protein secretion by abrogating receptor–coat interactions during ER export

    Get PDF
    Protein secretion is an essential process that drives cell growth, movement, and commu-nication. Protein traffic within the secretory pathway occurs via transport intermediatesthat bud from one compartment and fuse with a downstream compartment to delivertheir contents. Here, we explore the possibility that protein secretion can be selectivelyinhibited by perturbing protein–protein interactions that drive capture into transportvesicles. Human proprotein convertase subtilisin/kexin type 9 (PCSK9) is a determi-nant of cholesterol metabolism whose secretion is mediated by a specific cargo adaptorprotein, SEC24A. We map a series of protein–protein interactions between PCSK9, itsendoplasmic reticulum (ER) export receptor SURF4, and SEC24A that mediate secre-tion of PCSK9. We show that the interaction between SURF4 and SEC24A can beinhibited by 4-phenylbutyrate (4-PBA), a small molecule that occludes a cargo-bindingdomain of SEC24. This inhibition reduces secretion of PCSK9 and additional SURF4clients that we identify by mass spectrometry, leaving other secreted cargoes unaffected.We propose that selective small-molecule inhibition of cargo recognition by SEC24 is apotential therapeutic intervention for atherosclerosis and other diseases that are modu-lated by secreted proteins
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