Browsing by Subject "Working memory"

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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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    Paradoxical facilitation of working memory after basolateral amygdala damage
    (Public Library of Science, 2012) Morgan, Barak; Terburg, David; Thornton, Helena B; Stein, Dan J; van Honk, Jack
    Working memory is a vital cognitive capacity without which meaningful thinking and logical reasoning would be impossible. Working memory is integrally dependent upon prefrontal cortex and it has been suggested that voluntary control of working memory, enabling sustained emotion inhibition, was the crucial step in the evolution of modern humans. Consistent with this, recent fMRI studies suggest that working memory performance depends upon the capacity of prefrontal cortex to suppress bottom-up amygdala signals during emotional arousal. However fMRI is not well-suited to definitively resolve questions of causality. Moreover, the amygdala is neither structurally or functionally homogenous and fMRI studies do not resolve which amygdala sub-regions interfere with working memory. Lesion studies on the other hand can contribute unique causal evidence on aspects of brain-behaviour phenomena fMRI cannot "see". To address these questions we investigated working memory performance in three adult female subjects with bilateral basolateral amygdala calcification consequent to Urbach-Wiethe Disease and ten healthy controls. Amygdala lesion extent and functionality was determined by structural and functional MRI methods. Working memory performance was assessed using the Wechsler Adult Intelligence Scale-III digit span forward task. State and trait anxiety measures to control for possible emotional differences between patient and control groups were administered. Structural MRI showed bilateral selective basolateral amygdala damage in the three Urbach-Wiethe Disease subjects and fMRI confirmed intact functionality in the remaining amygdala sub-regions. The three Urbach-Wiethe Disease subjects showed significant working memory facilitation relative to controls. Control measures showed no group anxiety differences. Results are provisionally interpreted in terms of a 'cooperation through competition' networks model that may account for the observed paradoxical functional facilitation effect.
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    Using working memory to predict other domains within the learner profiler in an older adolescent sample
    (2023) Petersen, Asheeqa; Schrieff-Brown, Leigh
    Learning difficulties and disabilities (LDD) are the most frequently diagnosed of childhood developmental disorders. In South Africa (SA), however, a standard and nationally accepted tool has not yet been established for assessing LDDs and thus, specific incidence rates are not known. An underlying factor which may be important to consider in the context of LDDs is working memory (WM) which has been reported as playing a crucial role in learning and WM deficits appear to be higher in the context of LDDs. Thus, it may be imperative to adopt, and adapt to, new technologies that are both cost-effective and easily accessible, addressing the gap in resource availability. The Learner Profiler (LP) is an example of one such computerised test, being relatively cost effective and accessible. It should be noted, however, that research on the LP test method is particularly limited due to both a scarcity in the literature and the use of small sample sizes in said literature. The aim of this research was to investigate whether a computerised tool of WM on the LP could predict scores on other computerised cognitive domains on the LP. This quantitative study used a within-subjects experimental design to investigate the predictive value of LP WM module in other LP modules, namely, Visuospatial, Spelling, Missing Word, Word Choice, and New Word Spelling. The sample comprised of 1175 participants aged between 16 to 19 years old. At the time, participants attended a Technical Vocational Education and Training college (TVET) situated in an urban area in Gauteng, SA. The LP modules were administered during normal admissions processes at the college. To assess the predictive value of the LP WM module, the scores of the modules were analysed using multiple regression analyses.