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Browsing by Subject "Työmuisti"

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  • Työmuistiharjoittelun behavioraaliset ja hermostolliset vaikutukset 
    Tolonen, Tuija (2018)
    Working memory (WM), the ability to hold information in mind for short periods of time without active presentation of sensory stimuli is a crucial skill for goal-directed behaviour. WM is related to many other higher cognitive skills and specific neuropsychiatric conditions are associated with related deficits. Attempts have been made to improve WM by systematic cognitive training, and through this influence also other related cognitive skills. In this thesis, the behavioural and neuronal effects of WM training are reviewed. Based on current studies, both verbal and visual WM can be improved by training and the effects will last for several months. However, the effects of training on other cognitive skills outside WM, like reasoning and intelligence, have been moderate at best. On neural level, WM training changes the activation in brain areas related to WM, mainly frontal and parietal cortical regions and striatum. WM training also affects the functional and structural connections between these brain regions. WM training seems to improve executive functions rather than affect the size of working memory storages. Improvements in other than trained tasks seem to be based on cognitive functions that are shared between the tasks. On neural level, similar activation patterns between the tasks is related to these transfer effects.
  • Visuaalisen työmuistin neuraalinen perusta ja eri analyysimenetelmien merkitys 
    Luostarinen, Maaria (2017)
    Visual working memory is a cognitive system that is responsible of short term storage and manipulation of visual information. Working memory is divided to memorising, storage and recalling of the stimulus. This review concentrates in visual working memory studies that used functional magnetic resonance imaging (fMRI). FMRI is a spatially accurate and is based on changes in the brains blood circulation. The data from fMRI can be analysed with univariate or multivariate methods. These methods answer different research problems because of their different premises. The premise of univariate analysis is that the neural activation in one part of the brain is directly related to its function. In multivariate analysis, the neural activation is approached by observing the activations distribution, which means that different activation distributions in same parts of the brain can be related to different processes. The visual areas of the brain are located in the occipital lobe but, before multivariate analysis, the visual working memory has been associated with prefrontal cortex. After multivariate pattern analysis (MVPA) has increased in popularity the hypothesis, that visual areas have a part in visual working memory, has also generalised. Because of the activation distribution premise, the MVPA is a more sensitive method to analyse fMRI data. Still there have been different results in different MVPA using studies. Different memory tasks might also be partly responsible of different results. A visual working memory task always activates prefrontal and parietal cortices in addition to sensory cortex. Visual cortex seems to have the principal part and prefrontal and parietal cortices take part most likely in executive functions but they can’t be ruled out from storage either.

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