Browsing by Subject "Memory"

Now showing 1 - 5 of 5
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    Acquiring & forgetting a second language : a study of three children aged 5-11 years
    (1983) Keogh, Susan Elizabeth; Young, Douglas
    This investigation is concerned with what three children remembered or had forgotten of a second language after an interval of two years. An in-depth study, consisting of recognition and recall tests, was made of 13-year-old identical twin girls and their 9-year-old brother, who previously had been English/French bilinguals. A phenomenological approach was taken, which included the children's reaction to the tests, and their description of the personal framework within which the learning and forgetting had taken place. The findings, which are suggestive due to limited data, are: first, cognitive and maturational differences between the children caused the twins to retain more recognition and active recall of French than their brother; second, the twins showed a surprising difference in their recognition of French, pos9ibly caused by affective factors; third, all three children showed strongest recognition in the area of semantics, while in recall they retained phonology best; fourth, in the tests, habit memory and episodic memory were more durable than semantic memory. The investigation is a first step towards understanding how children forget a language in which they have been submersed.
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    Acute psychosocial stress enhances visuospatial in healthy males
    (SAGE Publications, 2013) Human, Robyn; Thomas, Kevin G F; Dreyer, Anna; Amod, Alysaa R; Wolf, Pedro S A; Jacobs, W Jake
    Previous research demonstrates that stress can disrupt a number of different cognitive systems, including verbal memory, working memory, and decision-making. Few previous studies have investigated relations between stress and visuospatial information processing, however, and none have examined relations among stress, visuospatial memory performance, and planning/ organisation of visuospatial information simultaneously. In total, 38 undergraduate males completed the copy trial of the Rey-Osterrieth Complex Figure Test. Those assigned randomly to the Stress group (n = 19) were then exposed to a laboratory-based psychosocial stressor; the others were exposed to an equivalent control condition. All then completed the delayed recall trial of the Rey-Osterrieth Complex Figure Test. Physiological and self-report measures of stress indicated that the induction manipulation was effective. Our predictions that control participants, relative to stressor-exposed participants, (a) take less time to complete the Rey-Osterrieth Complex Figure Test recall trial, (b) reproduce the figure more accurately on that trial, and (c) show better planning and more gestalt-based organisational strategies in creating that reproduction were disconfirmed. At recall, those with higher circulating cortisol levels (measured post-stress-induction) completed the drawing more accurately than those with lower circulating cortisol levels. Otherwise stated, the present data indicated that exposure to an acute psychosocial stressor enhanced visuospatial memory performance in healthy males. This data pattern is consistent with a previously proposed inverted U-shaped relationship between cortisol and cognition: Under this proposal, moderate levels of the hormone (as induced by the current manipulation) support optimal performance, whereas extremely high and extremely low levels impair performance.
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    BDNF polymorphisms are linked to poorer working memory performance, reduced cerebellar and hippocampal volumes and differences in prefrontal cortex in a Swedish elderly population
    (Public Library of Science, 2014) Brooks, Samantha J; Nilsson, Emil K; Jacobsson, Josefin A; Stein, Dan J; Fredriksson, Robert; Lind, Lars; Schiöth, Helgi B
    BACKGROUND: Brain-derived neurotrophic factor (BDNF) links learning, memory and cognitive decline in elderly, but evidence linking BDNF allele variation, cognition and brain structural differences is lacking. METHODS: 367 elderly Swedish men (n = 181) and women (n = 186) from Prospective Investigation of the Vasculature in Uppsala seniors (PIVUS) were genotyped and the BDNF functional rs6265 SNP was further examined in subjects who completed the Trail Making Task (TMT), verbal fluency task, and had a magnetic resonance imaging (MRI) scan. Voxel-based morphometry (VBM) examined brain structure, cognition and links with BDNF. RESULTS: The functional BDNF SNP (rs6265,) predicted better working memory performance on the TMT with positive association of the Met rs6265, and was linked with greater cerebellar, precuneus, left superior frontal gyrus and bilateral hippocampal volume, and reduced brainstem and bilateral posterior cingulate volumes. CONCLUSIONS: The functional BDNF polymorphism influences brain volume in regions associated with memory and regulation of sensorimotor control, with the Met rs6265 allele potentially being more beneficial to these functions in the elderly.
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    Inducible deletion of CD28 prior to secondary nippostrongylus brasiliensis infection impairs worm expulsion and recall of protective memory CD4 (+) T cell responses
    (Public Library of Science, 2014) Ndlovu, Hlumani; Darby, Mathew; Froelich, Monika; Horsnell, William; Lühder, Fred; Hünig, Thomas; Brombacher, Frank
    IL-13 driven Th2 immunity is indispensable for host protection against infection with the gastrointestinal nematode Nippostronglus brasiliensis. Disruption of CD28 mediated costimulation impairs development of adequate Th2 immunity, showing an importance for CD28 during the initiation of an immune response against this pathogen. In this study, we used global CD28−/− mice and a recently established mouse model that allows for inducible deletion of the cd28 gene by oral administration of tamoxifen (CD28−/loxCre+/−+TM) to resolve the controversy surrounding the requirement of CD28 costimulation for recall of protective memory responses against pathogenic infections. Following primary infection with N. brasiliensis, CD28−/− mice had delayed expulsion of adult worms in the small intestine compared to wild-type C57BL/6 mice that cleared the infection by day 9 post-infection. Delayed expulsion was associated with reduced production of IL-13 and reduced serum levels of antigen specific IgG1 and total IgE. Interestingly, abrogation of CD28 costimulation in CD28−/loxCre+/− mice by oral administration of tamoxifen prior to secondary infection with N. brasiliensis resulted in impaired worm expulsion, similarly to infected CD28−/− mice. This was associated with reduced production of the Th2 cytokines IL-13 and IL-4, diminished serum titres of antigen specific IgG1 and total IgE and a reduced CXCR5+ TFH cell population. Furthermore, total number of CD4+ T cells and B220+ B cells secreting Th1 and Th2 cytokines were significantly reduced in CD28−/− mice and tamoxifen treated CD28−/loxCre+/− mice compared to C57BL/6 mice. Importantly, interfering with CD28 costimulatory signalling before re-infection impaired the recruitment and/or expansion of central and effector memory CD4+ T cells and follicular B cells to the draining lymph node of tamoxifen treated CD28−/loxCre+/− mice. Therefore, it can be concluded that CD28 costimulation is essential for conferring host protection during secondary N. brasiliensis infection.
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    Postevent information and the impairment of eyewitness memory : a methodological examination
    (1989) Tredoux, Colin; Du Preez, Peter
    Recent work in the cognitive psychology of memory suggests that misleading information may permanently alter memory for an event. This work, which takes much of its impetus from the prospect of applying itself to the legal question of eyewitness evidence, has recently come under severe criticism. McCloskey & Zaragoza (1985a, 1985b) provide evidence to suggest that the experimental design used by almost all relevant studies is seriously flawed, and that results which appear to indicate the deleterious effect of misinformation on memory are artefactual. An analysis of the misinformation paradigm is presented here, with particular attention being paid to the claim of artifactuality. Two lines of approach are adopted in the analysis. In the first, the misinformation paradigm is assessed for its theoretical basis. The notion of 'application' that informs the paradigm is subjected to conceptual scrutiny, and the body of research that constitutes the paradigm is reviewed in terms of its applied orientation. In the second line of approach, the claim of artifactuality is investigated directly. Three methods are devised to test the claim of artifactuality. In two of these, post-hoc analyses are performed, one of which suggests that the claim of artifactuality is incorrect in at least some respects. The third method is constituted by an experiment which submits the claim of artifactuality to exhaustive empirical test. The results of the experiment support the claim that findings of memorial alteration are artefactual. The two lines of approach are united by showing how the experimental work developed out of the applied basis of the paradigm.· It is argued that the inadequacies in the experimental design reflect the impoverished theoretical basis of the research. It is further argued that the question regarding the effect that false information has on memory for an event is one that is still. eminently worth pursuing. A few preliminary remarks are made regarding applied considerations relevant to this pursuit.