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Showing papers by "Karl Magnus Petersson published in 2003"


Journal ArticleDOI
TL;DR: It is demonstrated that younger adults show increased activity during memory encoding in occipito-parietal and frontal brain regions after learning the mnemonic, which suggests that age-related differences in cognitive reserve capacity may reflect both a frontal processing deficiency and a posterior production deficiency.
Abstract: Cognitive studies show that both younger and older adults can increase their memory performance after training in using a visuospatial mnemonic, although age-related memory deficits tend to be magnified rather than reduced after training. Little is known about the changes in functional brain activity that accompany training-induced memory enhancement, and whether age-related activity changes are associated with the size of training-related gains. Here, we demonstrate that younger adults show increased activity during memory encoding in occipito-parietal and frontal brain regions after learning the mnemonic. Older adults did not show increased frontal activity, and only those elderly persons who benefited from the mnemonic showed increased occipito-parietal activity. These findings suggest that age-related differences in cognitive reserve capacity may reflect both a frontal processing deficiency and a posterior production deficiency.

264 citations


Journal ArticleDOI
TL;DR: Compared the activation patterns associated with tests of working memory, semantic memory and episodic memory, the results converged on a general involvement of four regions across memory tests, providing evidence that some PFC regions are engaged during many different memory tests.

258 citations


Journal ArticleDOI
TL;DR: The results suggest that episodic source memory is related to a functional network including the posterior precuneus and the left lateral prefrontal cortex that is activated during explicit retrieval of imagined pictures and results from the retrieval of item-context associations.

200 citations


Journal ArticleDOI
TL;DR: The results indicate that naming and identification of real objects, verbal fluency using ecologically relevant semantic criteria, verbal memory, and orientation are not affected by literacy or level of formal education, and verbal working memory assessed with digit span, verbal abstraction, long-term semanticMemory, and calculation are significantly affected by the level of literacy.
Abstract: The objectives of this article are to characterize the performance and to discuss the performance differences between literate and illiterate participants in a well-defined study population. We de- scribe the participant-selection procedure used to investigate this population. Three groups with similar sociocultural backgrounds living in a relatively homogeneous fishing community in southern Portugal were characterized in terms of socioeconomic and sociocultural background variables and compared on a simple neuropsychological test battery; specifically, a literate group with more than 4 years of education (n = 9), a literate group with 4 years of education (n = 26), and an illiterate group (n = 31) were included in this study. We compare and discuss our re- sults with other similar studies on the effects of literacy and illiteracy. The results indicate that naming and identification of real objects, verbal fluency using ecologically relevant semantic criteria, verbal memory, and orientation are not affected by literacy or level of formal education. In contrast, verbal working memory assessed with digit span, verbal abstraction, long-term se- mantic memory, and calculation (i.e., multiplication) are significantly affected by the level of lit- eracy. We indicate that it is possible, with proper participant-selection procedures, to exclude general cognitive impairment and to control important sociocultural factors that potentially could introduce bias when studying the specific effects of literacy and level of formal education on cognitive brain function.

60 citations


Journal ArticleDOI
TL;DR: The results suggest that the irrelevant speech effect is correlated with and thus tentatively may be explained in terms of a suppression of components of the verbal working memory network as outlined.

45 citations


Journal ArticleDOI
TL;DR: The levels-of-processing (LOP) effect using visual material in a behavioral and a corresponding PET study is investigated and it is suggested that the anterior medial superior frontal region is related to aspects of self-referential semantic processing and the inferior parts of the anterior cingulate as well as the medial orbitofrontal cortex are related to affective processing.

22 citations


01 Jan 2003
TL;DR: For instance, the authors found no significant link between socioeconomic status and aphasia severity and recovery, while no significant relationship between socio-economic status and severity has been established in studies of the influence of educational level and literacy (or illiteracy).
Abstract: Is there a relation between socioeconomic factors and aphasia severity and recovery? Connor, Obler, Tocco, Fitzpatrick, and Albert (2001) describe correlations between the educational level and socioeconomic status of aphasic subjects with aphasia severity and subsequent recovery. As stated in the introduction by Connor et al. (2001), studies of the influence of educational level and literacy (or illiteracy) on aphasia severity have yielded conflicting results, while no significant link between socioeconomic status and aphasia severity and recovery has been established. In this brief note, we will comment on their findings and conclusions, beginning first with a brief review of literacy and aphasia research, and complexities encountered in these fields of investigation. This serves as a general background to our specific comments on Connor et al. (2001), which will be focusing on methodological issues and the importance of taking normative values in consideration when subjects with different socio-cultural or socio-economic backgrounds are assessed. 2003 Elsevier Science (USA). All rights reserved.

11 citations


Journal ArticleDOI
TL;DR: Commenting on the correlations between the educational level and socioeconomic status of aphasic subjects with aphasia severity and subsequent recovery focuses on methodological issues and the importance of taking normative values in consideration when subjects with different socio-cultural or socio-economic backgrounds are assessed.

9 citations