| 1. |
- Bäckman, Lars, et al.
(författare)
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Attentional demands and recall of verbal and color information in action events
- 1993
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Ingår i: Scandinavian Journal of Psychology. - : Blackwell Publishing. - 0036-5564 .- 1467-9450. ; 34:3, s. 246-254
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Tidskriftsartikel (refereegranskat)abstract
- Two experiments addressed the influence of secondary task performance at encoding on recall of different features of subject‐performed tasks (SPTs) involving objects (e.g., turn the wallet). In Experiment 1, memory for verbs and colors of objects was assessed, with object names serving as cues. In Experiment 2, object and color memory were assessed, with verbs serving as cues. Results from both experiments indicated a greater deterioration of memory performance under divided attention for verbal features than for colors. In addition, intention to remember did not affect performance for any feature in either experiment. The overall pattern of outcome is discussed relative to the view that encoding of verbal features of SPTs is more attention‐demanding than encoding of physical task features, such as color.
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| 2. |
- Kormi-Nouri, Reza, 1954-, et al.
(författare)
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The dual-conception view reexamined : attentional demands and the encoding of verbal and physical information in action events
- 1994
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Ingår i: Psychological Research. - : Springer-Verlag New York. - 0340-0727 .- 1430-2772. ; 57:1, s. 42-46
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Tidskriftsartikel (refereegranskat)abstract
- In two experiments the influence of attentional demands at encoding on recall of different features of subject-performed tasks (SPTs) was studied. In Experiment 1, memory of verbs and colors of objects was tested, with object names serving as cues. In Experiment 2, object and color memory were tested, with verbs serving as cues. Results from both experiments indicated that SPTs were affected by divided attention at encoding. In contrast to previous research, verbal and physical properties of SPTs were not differently affected by the requirements of dual-task performance (i.e., the combination of an SPT task and a secondary task). The results are discussed in terms of the nature of the secondary task.
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| 3. |
- Falk, Lars, et al.
(författare)
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Genotyping of Chlamydia trachomatis would improve contact tracing
- 2003
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Ingår i: Sexually Transmitted Diseases. - : Ovid Technologies (Wolters Kluwer Health). - 0148-5717 .- 1537-4521. ; 30:3, s. 205-210
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Tidskriftsartikel (refereegranskat)abstract
- Background: The reported number of genital Chlamydia trachomatis infections has increased 15% annually since 1997 in Sweden. Inaccurate partner notification might be one reason.Goal: The goals were to determine if genotyping of C trachomatis would improve partner notification and to study the duration of infection.Study Design: Sexual networks were constructed. C trachomatis isolates from 231 individuals attending the Örebro STD clinic during 1 year were typed by sequencing of the omp1 gene.Results: All individuals were traced and diagnoses were established in 30 of 161 networks. More than one genotype was seen in seven networks. The mean duration of C trachomatis infection in each network was calculated to be 23 weeks.Conclusion: Genotyping could be a useful tool in partner notification when there are discrepant or uncommon genotypes. Limited clinic catchment areas create information difficulties that obstruct accurate contact tracing.
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| 4. |
- Jurstrand, Margaretha, et al.
(författare)
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Characterization of Chlamydia trachomatis omp1 genotypes among sexually transmitted disease patients in Sweden
- 2001
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Ingår i: Journal of Clinical Microbiology. - 0095-1137 .- 1098-660X. ; 39:11, s. 3915-3919
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Tidskriftsartikel (refereegranskat)abstract
- A method for detection and genotyping of genital Chlamydia trachomatis infections based on omp1 gene amplification and sequencing was developed. DNA was extracted from urogenital or urine samples using a Chelex-based method, and an approximately 1,100-bp-long fragment from the omp1 gene was directly amplified and sequenced. Genotyping was performed by BLAST similarity search, and phylogenetic tree analysis was used to illustrate the evolutionary relationships between clinical isolates and reference strains. The method was used to determine the genotypes of C. trachomatis in 237 positive urogenital and/or urine specimens collected at a Swedish sexually transmitted disease clinic during 1 year. The most common genotypes corresponded to serotypes E (47%) and F (17%). The omp1 gene was highly conserved for genotype E (106 of 112 samples without any mutation) and F (41 of 42 samples without any mutation) strains but appear slightly less conserved for genotypes G (n = 6) and H (n = 6), where the sequences displayed one to four nucleotide substitutions relative to the reference sequence. Genotyping of samples collected at the follow-up visit indicated that two patients had become reinfected, while three other patients suffered treatment failure or reinfection. One woman appeared to have a mixed infection with two different C. trachomatis strains. This omp1 genotyping method had a high reproducibility and could be used for epidemiological characterization of sexually transmitted Chlamydia infections.
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| 5. |
- Kalpouzos, Grégoria, et al.
(författare)
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Higher Striatal Iron Concentration is Linked to Frontostriatal Underactivation and Poorer Memory in Normal Aging
- 2017
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Ingår i: Cerebral Cortex. - : Oxford University Press. - 1047-3211 .- 1460-2199. ; 27:6, s. 3427-3436
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Tidskriftsartikel (refereegranskat)abstract
- In the brain, intracellular iron is essential for cellular metabolism. However, an overload of free iron is toxic, inducing oxidative stress and cell death. Although an increase of striatal iron has been related to atrophy and impaired cognitive performance, the link between elevated iron and altered brain activity in aging remains unexplored. In a sample of 37 younger and older adults, we examined whether higher striatal iron concentration could underlie age-related differences in frontostriatal activity induced by mental imagery of motor and non-motor scenes, and poorer recall of the scenes. Higher striatal iron concentration was linked to underrecruitment of frontostriatal regions regardless of age and striatal volume, the iron-activity association in right putamen being primarily driven by the older adults. In older age, higher striatal iron was related to poorer memory. Altered astrocytic functions could account for the link between brain iron and brain activity, as astrocytes are involved in iron buffering, neurovascular coupling, and synaptic activity. Our preliminary findings, which need to be replicated in a larger sample, suggest a potential frontostriatal target for intervention to counteract negative effects of iron accumulation on brain function and cognition.
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| 6. |
- Li, Xin, et al.
(författare)
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Influence of the DRD2/ANKK1 Taq1A polymorphism on caudate volume in older adults without dementia
- 2018
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Ingår i: Brain Structure and Function. - : Springer. - 1863-2653 .- 1863-2661. ; 223:6, s. 2653-2662
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Tidskriftsartikel (refereegranskat)abstract
- Dopaminergic neuromodulation is critically important for brain and cognitive integrity. The DRD2/ANKK1 Taq1A polymorphism is associated with striatal dopamine (DA) D2 receptor availability. Some previous studies have found that the A allele of the Taq1A polymorphism influences brain structure, but the results are inconsistent, likely due to population heterogeneity and small sample sizes. We investigated the genetic effect on caudate volume in a large sample of older adults without dementia. Results show that A-allele carriers have smaller caudate volume compared to non-carriers in relatively older adults (n = 167; Mage = 77.8 years), whereas the genotype did not influence caudate volume in a younger age group (n = 220; Mage = 62.8 years). Cognitive performance was not significantly affected by the DRD2 gene. Our findings extend previous observations by showing magnified genetic effects on brain volume in old age, and provide evidence for a link between a DA-related genetic polymorphism and grey matter volume in a brain region within the nigrostriatal dopaminergic pathway.
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| 7. |
- Li, Xin, et al.
(författare)
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The relationship of age and DRD2 polymorphisms to frontostriatal brain activity and working memory performance
- 2019
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Ingår i: Neurobiology of Aging. - : Elsevier. - 0197-4580 .- 1558-1497. ; 84, s. 189-199
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Tidskriftsartikel (refereegranskat)abstract
- Dopamine (DA) in both prefrontal cortex (PFC) and caudate nucleus is critical for working memory (WM) function. The C957T and Taq1A polymorphisms of the DRD2 gene are related to DA D2 receptor densities in PFC and striatum. Using functional MRI, we investigated the relationship of age and these 2 DRD2 gene polymorphisms to WM function and examined possible age by gene interactions. Results demonstrated less caudate activity for older adults (70-80 years; n = 112) compared with the younger age group (25-65 years; n = 191), suggesting age-related functional differences in this region. Importantly, there was a gene-related difference regarding WM performance and frontostriatal brain activity. Specifically, better WM performance and greater activity in PFC were found among C957T C allele carriers. Combined genetic markers for increased DA D2 receptor density were associated with greater caudate activity and higher WM updating performance. The genetic effects on blood oxygen level-dependent activity were only observed in older participants, suggesting magnified genetic effects in aging. Our findings emphasize the importance of DA-related genes in regulating WM functioning in aging and demonstrate a positive link between DA and brain activation in the frontostriatal circuitry.
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| 8. |
- Li, Xin, et al.
(författare)
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White-matter integrity and working memory : Links to aging and dopamine-related genes
- 2022
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Ingår i: eNeuro. - : Society for Neuroscience. - 2373-2822. ; 9:2
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Tidskriftsartikel (refereegranskat)abstract
- Working memory, a core function underlying many higher-level cognitive processes, requires cooperation of multiple brain regions. White matter refers to myelinated axons, which are critical to inter-regional brain communication. Past studies on the association between white-matter integrity and working memory have yielded mixed findings. Using voxel-wise tract-based spatial statistics analysis, we investigated this relationship in a sample of 328 healthy adults from 25 to 80 years of age. Given the important role of dopamine (DA) in working-memory functioning and white matter, we also analyzed the effects of dopamine-related genes on them. There were associations between white-matter integrity and working memory in multiple tracts, indicating that working-memory functioning relies on global connections between different brain areas across the adult lifespan. Moreover, a mediation analysis suggested that white-matter integrity contributes to age-related differences in working memory. Finally, there was an effect of the COMT Val158Met polymorphism on white-matter integrity, such that Val/Val carriers had lower fractional anisotropy (FA) values than any Met carriers in the internal capsule, corona radiata, and posterior thalamic radiation. As this polymorphism has been associated with dopaminergic tone in the prefrontal cortex (PFC), this result provides evidence for a link between DA neurotransmission and white matter. Taken together, the results support a link between white-matter integrity and working memory and provide evidence for its interplay with age and DA-related genes.
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| 9. |
- Papenberg, Goran, et al.
(författare)
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Genetics and Functional Imaging : Effects of APOE, BDNF, COMT, and KIBRA in Aging
- 2015
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Ingår i: Neuropsychology Review. - : Springer. - 1040-7308 .- 1573-6660. ; 25:1, s. 47-62
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Forskningsöversikt (refereegranskat)abstract
- Increasing evidence from cross-sectional and longitudinal molecular-genetic studies suggests that effects of common genetic variations on cognitive functioning increase with aging. We review the influence of candidate genes on brain functioning in old age, focusing on four genetic variations that have been extensively investigated: APOE, BDNF, COMT, and KIBRA. Similar to the behavioral evidence, there are reports from age-comparative studies documenting stronger genetic effects on measures of brain functioning in older adults compared to younger adults. This pattern suggests disproportionate impairments of neural processing among older individuals carrying disadvantageous genotypes. We discuss various factors, including gene-gene interactions, study population characteristics, lifestyle factors, and diseases, that need to be considered in future studies and may help understand inconsistent findings in the extant literature.
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| 10. |
- Persson, Jonas, 1971-, et al.
(författare)
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A positive influence of basal ganglia iron concentration on implicit sequence learning
- 2020
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Ingår i: Brain Structure and Function. - : Springer. - 1863-2653 .- 1863-2661. ; 225:2, s. 735-749
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Tidskriftsartikel (refereegranskat)abstract
- Iron homeostasis is important for maintaining normal physiological brain functioning. In two independent samples, we investigate the link between iron concentration in the basal ganglia (BG) and implicit sequence learning (ISL). In Study 1, we used quantitative susceptibility mapping and task-related fMRI to examine associations among regional iron concentration measurements, brain activation, and ISL in younger and older adults. In Study 2, we examined the link between brain iron and ISL using a metric derived from fMRI in an age-homogenous sample of older adults. Three main findings were obtained. First, BG iron concentration was positively related to ISL in both studies. Second, ISL was robust for both younger and older adults, and performance-related activation was found in fronto-striatal regions across both age groups. Third, BG iron was positively linked to task-related BOLD signal in fronto-striatal regions. This is the first study investigating the relationship among brain iron accumulation, functional brain activation, and ISL, and the results suggest that higher brain iron concentration may be linked to better neurocognitive functioning in this particular task.
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