| 1. |
- Avelar-Pereira, Barbara, et al.
(författare)
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Increased functional homotopy of the prefrontal cortex is associated with corpus callosum degeneration and working memory decline
- 2020
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Ingår i: Neurobiology of Aging. - : Elsevier. - 0197-4580 .- 1558-1497. ; 96, s. 68-78
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Tidskriftsartikel (refereegranskat)abstract
- Functional homotopy reflects the link between spontaneous activity in a voxel and its counterpart in the opposite hemisphere. Alterations in homotopic functional connectivity (FC) are seen in normal aging, with highest and lowest homotopy being present in sensory-motor and higher-order regions, respectively. Homotopic FC relates to underlying structural connections, but its neurobiological underpinnings remain unclear. The genu of the corpus callosum joins symmetrical parts of the prefrontal cortex (PFC) and is susceptible to age-related degeneration, suggesting that PFC homotopic connectivity is linked to changes in white-matter integrity. We investigated homotopic connectivity changes and whether these were associated with white-matter integrity in 338 individuals. In addition, we examined whether PFC homotopic FC was related to changes in the genu over 10 years and working memory over 5 years. There were increases and decreases in functional homotopy, with the former being prevalent in subcortical and frontal regions. Increased PFC homotopic FC was partially driven by structural degeneration and negatively associated with working memory, suggesting that it reflects detrimental age-related changes. (C) 2020 The Author(s). Published by Elsevier Inc.
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| 2. |
- Bäckman, Lars, et al.
(författare)
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Dopamine D(1) receptors and age differences in brain activation during working memory
- 2011
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Ingår i: Neurobiology of Aging. - Fayetteville, N.Y : Elsevier. - 0197-4580 .- 1558-1497. ; 32:10, s. 1849-1856
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Tidskriftsartikel (refereegranskat)abstract
- In an fMRI study, 20 younger and 20 healthy older adults were scanned while performing a spatial working-memory task under two levels of load. On a separate occasion, the same subjects underwent PET measurements using the radioligand [(11)C] SCH23390 to determine dopamine D(1) receptor binding potential (BP) in caudate nucleus and dorsolateral prefrontal cortex (DLPFC). The fMRI study revealed a significant load modulation of brain activity (higher load>lower load) in frontal and parietal regions for younger, but not older, adults. The PET measurements showed marked age-related reductions of D(1) BP in caudate and DLPFC. Statistical control of caudate and DLPFC D(1) binding eliminated the age-related reduction in load-dependent BOLD signal in left frontal cortex, and attenuated greatly the reduction in right frontal and left parietal cortex. These findings suggest that age-related alterations in dopaminergic neurotransmission may contribute to underrecruitment of task-relevant brain regions during working-memory performance in old age.
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| 3. |
- Dintica, Christina S., et al.
(författare)
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Tooth loss is associated with accelerated cognitive decline and volumetric brain differences : a population-based study
- 2018
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Ingår i: Neurobiology of Aging. - : Elsevier BV. - 0197-4580 .- 1558-1497. ; 67, s. 23-30
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Tidskriftsartikel (refereegranskat)abstract
- Tooth loss has been related to cognitive impairment; however, its relation to structural brain differences in humans is unknown. Dementia-free participants (n = 2715) of age >= 60 years were followed up for up to 9 years. A subsample (n = 394) underwent magnetic resonance imaging at baseline. Information on tooth loss was collected at baseline, and cognitive function was assessed using the Mini-Mental State Examination at baseline and at follow-ups. Data were analyzed using linear mixed effects models and linear regression models. At baseline, 404 (14.9%) participants had partial tooth loss, and 206 (7.6%) had complete tooth loss. Tooth loss was significantly associated with a steeper cognitive decline (beta: -0.18, 95% confidence interval [CI]: -0.24 to -0.11) and remained significant after adjusting for or stratifying by potential confounders. In cross-sectional analyses, persons with complete or partial tooth loss had significantly lower total brain volume (beta: -28.89, 95% CI: -49.33 to -8.45) and gray matter volume (beta: -22.60, 95% CI: -38.26 to -6.94). Thus, tooth loss may be a risk factor for accelerated cognitive aging.
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| 4. |
- Karalija, Nina, 1984-, et al.
(författare)
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Sex differences in dopamine integrity and brain structure among healthy older adults : Relationships to episodic memory
- 2021
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Ingår i: Neurobiology of Aging. - : Elsevier. - 0197-4580 .- 1558-1497. ; 105, s. 272-279
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Tidskriftsartikel (refereegranskat)abstract
- Normal brain aging is a multidimensional process that includes deterioration in various brain structures and functions, with large heterogeneity in patterns and rates of decline. Sex differences have been reported for various cognitive and brain parameters, but little is known in relation to neuromodulatory aspects of brain aging. We examined sex differences in dopamine D2-receptor (D2DR) availability in relation to episodic memory, but also, grey-matter volumes, white-matter lesions, and cerebral perfusion in healthy older adults (n = 181, age: 64-68 years) from the Cognition, Brain, and Aging study. Women had higher D2DR availability in midbrain and left caudate and putamen, as well as superior episodic memory performance. Controlling for left caudate D2DR availability attenuated sex differences in memory performance. In men, lower left caudate D2DR levels were associated with lower cortical perfusion and higher burden of white-matter lesions, as well as with episodic memory performance. However, sex was not a significant moderator of the reported links to D2DR levels. Our findings suggest that sex differences in multiple associations among DA receptor availability, vascular factors, and structural connectivity contribute to sex differences in episodic memory. Future longitudinal studies need to corroborate these patterns by lead-lag associations. This manuscript is part of the Special Issue entitled 'Cognitive Neuroscience of Healthy and Pathological Aging' edited by Drs. M. N. Rajah, S. Belleville, and R. Cabeza.
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| 5. |
- Köhncke, Ylva, et al.
(författare)
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Three-year changes in leisure activities are associated with concurrent changes in white matter microstructure and perceptual speed in individuals aged 80 years and older
- 2016
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Ingår i: Neurobiology of Aging. - : Elsevier BV. - 0197-4580 .- 1558-1497. ; 41, s. 173-186
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Tidskriftsartikel (refereegranskat)abstract
- Accumulating evidence suggests that engagement in leisure activities is associated with favorable trajectories of cognitive aging, but little is known about brain changes related to both activities and cognition. White matter microstructure shows experience-dependent plasticity and declines in aging. Therefore, we investigated the role of change in white matter microstructure in the activities-cognition link. We used repeated assessments of engagement, perceptual speed, and white matter microstructure (probed with diffusion tensor imaging) in a population-based sample of individuals over 80 years without dementia (n = 442, M-age = 85.1; n = 70 for diffusion tensor imaging; 2 occasions 3 years apart). Using multivariate latent change modeling, we observed positive correlations among changes in predominantly social activities, white matter microstructure, and perceptual speed. Interindividual differences in change in white matter microstructure statistically accounted for the association between change in leisure activities and change in perceptual speed. However, as analyses are based on observational data from 2 measurement occasions, causality remains unclear.
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| 6. |
- Larsson, Maria, et al.
(författare)
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Olfactory memory in the old and very old : relations to episodic and semantic memory and APOE genotype
- 2016
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Ingår i: Neurobiology of Aging. - : Elsevier BV. - 0197-4580 .- 1558-1497. ; 38, s. 118-126
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Tidskriftsartikel (refereegranskat)abstract
- The neuroanatomical organization that underlies olfactory memory is different from that of other memory types. The present work examines olfactory memory in an elderly population-based sample (Swedish National Study on Aging and Care in Kungsholmen) aged 60-100 years (n = 2280). We used structural equation modeling to investigate whether olfactory memory in old age is best conceptualized as a distinct category, differentiated from episodic and semantic memory. Further, potential olfactory dedifferentiation and genetic associations (APOE) to olfactory function in late senescence were investigated. Results are in support of a 3-factor solution where olfactory memory, as indexed by episodic odor recognition and odor identification, is modeled separately from episodic and semantic memory for visual and verbal information. Increasing age was associated with poorer olfactory memory performance, and observed age-related deficits were further exacerbated for carriers of the APOE epsilon 4 allele; these effects tended to be larger for olfactory memory compared to episodic and semantic memory pertaining to other sensory systems (vision, auditory). Finally, stronger correlations between olfactory and episodic memory, indicating dedifferentiation, were observed in the older age groups.
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| 7. |
- Li, Shu-Chen, et al.
(författare)
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Aging magnifies the effects of dopamine transporter and D2 receptor genes on backward serial memory
- 2013
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Ingår i: Neurobiology of Aging. - : Elsevier BV. - 0197-4580 .- 1558-1497. ; 34:1, s. 358.e1-358.e10
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Tidskriftsartikel (refereegranskat)abstract
- Aging compromises dopamine transporter (DAT) and receptor mechanisms in the frontostriatal circuitry. In a sample of 1288 younger and older adults, we investigated (i) whether individual differences in genotypes of the DAT gene (i.e., SLC6A3, the DAT variable number of tandem repeat 9/9, 9/10, and 10/10) and in the D2 receptor (DRD2) gene (i.e., the C957T [rs6277] CC and any T) interactively contribute to phenotype variations in episodic memory performance; and (ii) whether these genetic effects are magnified in older adults, because of considerable declines in the dopamine functions. Our results showed that carrying genotypes associated with higher levels of striatal synaptic dopamine (DAT 9/9) and higher density of extrastriatal D2 receptors (C957T CC) were associated with better backward serial recall, an episodic memory task with high encoding and retrieval demands. Critically, the gene-gene interaction effect was reliably stronger in older than in younger adults. In line with the resource modulation hypothesis, our findings suggest that aging-related decline in brain phenotypes (e.g., dopamine functions) could alter the relations between genotypes and behavioral phenotypes (e.g., episodic memory).
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| 8. |
- 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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| 9. |
- Li, Yuanjing, et al.
(författare)
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Association of white matter hyperintensity accumulation with domain-specific cognitive decline : a population-based cohort study
- 2023
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Ingår i: Neurobiology of Aging. - 0197-4580 .- 1558-1497. ; 132, s. 100-108
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Tidskriftsartikel (refereegranskat)abstract
- We investigated the association of load and accumulation of white matter hyperintensities (WMHs) with rate of cognitive decline. This population-based study included 510 dementia-free people (age ≥60 years) who had repeated measures of global and regional (lobar, deep, periventricular) WMHs up to 6 years (from 2001–2003 to 2007–2010) and repeated measures of cognitive function (episodic memory, semantic memory, category fluency, letter fluency, executive function, perceptual speed) up to 15 years (from 2001–2004 to 2016–2019). We found that greater baseline loads of global and regional WMHs were associated with faster decline in letter fluency, perceptual speed, and global cognition. Furthermore, faster accumulation of global, deep, and periventricular WMHs was related to accelerated cognitive decline, primarily in perceptual speed. These data show that WMHs are associated with decline in perceptual speed rather than episodic or semantic memory and that cognitive change is more vulnerable to WMH accumulations in deep and periventricular regions.
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| 10. |
- Li, Yuanjing, et al.
(författare)
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Progression of neuroimaging markers of cerebral small vessel disease in older adults : A 6-year follow-up study
- 2022
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Ingår i: Neurobiology of Aging. - : Elsevier BV. - 0197-4580 .- 1558-1497. ; 112, s. 204-211
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Tidskriftsartikel (refereegranskat)abstract
- We investigated progression and interrelationships of cerebral small vessel disease (cSVD) markers. This population-based cohort study included 325 participants (age ≥ 60 years) who had repeated measures of cSVD markers over 6 years: white-matter hyperintensity (WMH), perivascular spaces (PVS), lacunes, and grey-matter (GM) and ventricular volumes. We found that all cSVD markers, except PVS, progressed faster with increasing age. Regional WMH progressed faster in males and less-educated people (p < 0.05). Each 10-point increment in global WMH score was associated with multi-adjusted hazard ratio of 1.78 (95% CI = 1.50‒2.10) for incident lacunes and multi-adjusted β-coefficients of 0.15 (0.08–0.22), -0.37 (-0.58‒-0.16), and 0.11 (0.03‒0.18) for annual changes of global WMH score, GM volume, and ventricular volume, respectively. The corresponding figures associated with per 10-PVS increment were 1.14 (1.01‒1.28), 0.07 (0.03‒0.11), -0.18 (-0.32‒-0.04), and 0.02 (-0.03‒0.07). Prevalent lacunes were related to multi-adjusted β-coefficients of 0.29 (0.00‒0.58), 0.22 (0.05‒0.38), 0.10 (0.01‒0.18), and -0.93 (-1.83‒-0.03) for annual changes of global, deep, and periventricular WMH scores and GM volume, respectively. These results suggest that cSVD progresses faster in older, male, and less-educated people, and that greater loads of WMH, PVS, and lacunes anticipate faster cSVD progression.
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