Browsing by Author "Luostarinen, Maaria"

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.