| 11. |
- Bäckman, Lars, et al.
(författare)
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Linking cognitive aging to alterations in dopamine neurotransmitter functioning : Recent data and future avenues
- 2010
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Ingår i: Neuroscience and Biobehavioral Reviews. - : Elsevier BV. - 0149-7634 .- 1873-7528. ; 34:5, s. 670-677
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Forskningsöversikt (refereegranskat)abstract
- Molecular-imaging studies of dopaminergic neurotransmission measure biomarkers of dopamine (DA), such as the DA transporter and D(1) and D(2) receptor densities in the living brain. These studies indicate that individual differences in DA functions are linked to cognitive performance irrespective of age, and serve as powerful mediators of age-related decline in executive functioning, episodic memory, and perceptual speed. This focused review targets several recent findings pertaining to these relationships. Specifically, we discuss novel evidence concerning (a) the role of DA in within-person cognitive variability; (b) age-related differences in DA release during cognitive processing; (c) DA release following cognitive training in younger and older adults; and (d) the relationship between DA and task-induced functional brain activity. Based on these lines of empirical inquiry, we outline a series of avenues for future research on aging, DA, and cognition.
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| 12. |
- Bäckman, Lars, et al.
(författare)
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The correlative triad among aging, dopamine, and cognition : current status and future prospects.
- 2006
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Ingår i: Neuroscience and Biobehavioral Review. - : Elsevier BV. - 0149-7634. ; 30:6, s. 791-807
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The brain neuronal systems defined by the neurotransmitter dopamine (DA) have since long a recognized role in the regulation of motor functions. More recently, converging evidence from patient studies, animal research, pharmacological intervention, and molecular genetics indicates that DA is critically implicated also in higher-order cognitive functioning. Many cognitive functions and multiple markers of striatal and extrastriatal DA systems decline across adulthood and aging. Research examining the correlative triad among adult age, DA, and cognition has found strong support for the view that age-related DA losses are associated with age-related cognitive deficits. Future research strategies for examining the DA-cognitive aging link include assessing (a) the generality/specificity of the effects; (b) the relationship between neuromodulation and functional brain activation; and (c) the release of DA during actual task performance.
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| 13. |
- Cabeza, Roberto, et al.
(författare)
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Maintenance, reserve and compensation : the cognitive neuroscience of healthy ageing
- 2018
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Ingår i: Nature Reviews Neuroscience. - : Nature Publishing Group. - 1471-003X .- 1471-0048. ; 19:11, s. 701-710
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Forskningsöversikt (refereegranskat)abstract
- Cognitive ageing research examines the cognitive abilities that are preserved and/or those that decline with advanced age. There is great individual variability in cognitive ageing trajectories. Some older adults show little decline in cognitive ability compared with young adults and are thus termed ‘optimally ageing’. By contrast, others exhibit substantial cognitive decline and may develop dementia. Human neuroimaging research has led to a number of important advances in our understanding of the neural mechanisms underlying these two outcomes. However, interpreting the age-related changes and differences in brain structure, activation and functional connectivity that this research reveals is an ongoing challenge. Ambiguous terminology is a major source of difficulty in this venture. Three terms in particular — compensation, maintenance and reserve — have been used in a number of different ways, and researchers continue to disagree about the kinds of evidence or patterns of results that are required to interpret findings related to these concepts. As such inconsistencies can impede progress in both theoretical and empirical research, here, we aim to clarify and propose consensual definitions of these terms.
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| 14. |
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| 15. |
- Czernochowski, Daniela, et al.
(författare)
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When binding matters: An ERP analysis of the development of recollection and familiarity in childhood
- 2004
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Ingår i: Bound in Memory: Insights from behavioral and neuropsychological research. - 3832228713 ; , s. 93-128
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Dual process models of recognition memory assume that memory retrieval can be based on two distinct processes: an assessment of a context-free feeling of familiarity or on the reinstatement of specific context attributes that have been bound together to form a representation of the study episode during encoding (recollection). Recent neurophysiological evidence suggests that familiarity and recollection are mediated by different medial temporal lobe circuitries and accomplished by different binding mechanisms. The assessment of familiarity has been associated with intra-item binding mechanisms of the perirhinal cortex, whereas the explicit retrieval of specific details of a study episode depends on inter-item binding mechanisms mediated by the hippocampal formation and the prefrontal cortex. A related line of evidence for the independence of these memory processes comes from the examination of patients with selective lesions: Vargha-Khadem et al. (1997) reported three cases of early bilateral hypoxic lesions restricted to the hippocampus. Although these patients were unable to acquire and to retrieve episodic information, they were unlike most adult amnesics clearly able to acquire semantic knowledge after their injury. We examined the developmental aspects of recollection and familiarity by means of an event-related potential (ERP) study in two groups of children (6–8 years, 10–12 years) and young adults (20–29 years). Topographical differences of ERP components between the age groups were found in the memory task, but not in an auditory discrimination (oddball) task, suggesting that ERP differences between groups can be ascribed to differential memory processes rather than to general age differences. Our findings support the view of a differential development of recollection and familiarity. We discuss these findings in the light of different memory strategies in children as indicated by a generally lower performance level and a more conservative response criterion.
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| 16. |
- de Frias, Cindy, et al.
(författare)
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Revisiting the dedifferebtion hypothesis with longitudinal multi-cohort data
- 2007
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Ingår i: Intelligence. ; 35, s. 381-392
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Tidskriftsartikel (refereegranskat)abstract
- The present longitudinal multi-cohort study examines whether interindividual variability in cognitive performance and change increases in old age, and whether associations among developments of different cognitive functions increase with adult age. Multivariate multiple-group latent growth modeling was applied to data from narrow cohorts separated by five years of age. Tests assessing episodic recall, semantic knowledge, semantic fluency, and visuospatial ability were administered to 1000 non-demented adults (initially aged 35–80 years), participating in the Betula Project at three occasions over a 10-year period. Greater interindividual differences in change were noted in older age groups. Age-related increases in correlations among performance scores were noted for different cognitive measures beginning in old age, but not earlier. Our study supports a dynamic view of dedifferentiation of cognitive aging.
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| 17. |
- Filevich, Elisa, et al.
(författare)
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Day2day : Investigating daily variability of magnetic resonance imaging measures over half a year
- 2017
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Ingår i: BMC Neuroscience. - : Springer Science and Business Media LLC. - 1471-2202. ; 18:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Most studies of brain structure and function, and their relationships to cognitive ability, have relied on inter-individual variability in magnetic resonance (MR) images. Intra-individual variability is often ignored or implicitly assumed to be equivalent to the former. Testing this assumption empirically by collecting enough data on single individuals is cumbersome and costly. We collected a dataset of multiple MR sequences and behavioural covariates to quantify and characterize intra-individual variability in MR images for multiple individuals. Methods and design: Eight participants volunteered to undergo brain scanning 40-50 times over the course of 6 months. Six participants completed the full set of sessions. T1-weighted, T2*-weighted during rest, T2-weighted high-resolution hippocampus, diffusion-tensor imaging (DTI), and proton magnetic resonance spectroscopy sequences were collected, along with a rich set of stable and time-varying physical, behavioural and physiological variables. Participants did not change their lifestyle or participated in any training programs during the period of data collection. Conclusion: This imaging dataset provides a large number of MRI scans in different modalities for six participants. It enables the analysis of the time course and correlates of intra-individual variability in structural, chemical, and functional aspects of the human brain.
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| 18. |
- Fjell, Anders M., et al.
(författare)
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Poor Self-Reported Sleep is Related to Regional Cortical Thinning in Aging but not Memory Decline-Results From the Lifebrain Consortium
- 2021
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Ingår i: Cerebral Cortex. - : Oxford University Press. - 1047-3211 .- 1460-2199. ; 31:4, s. 1953-1969
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Tidskriftsartikel (refereegranskat)abstract
- We examined whether sleep quality and quantity are associated with cortical and memory changes in cognitively healthy participants across the adult lifespan. Associations between self-reported sleep parameters (Pittsburgh Sleep Quality Index, PSQI) and longitudinal cortical change were tested using five samples from the Lifebrain consortium (n = 2205, 4363 MRIs, 18-92 years). In additional analyses, we tested coherence with cell-specific gene expression maps from the Allen Human Brain Atlas, and relations to changes in memory performance. "PSQI # 1 Subjective sleep quality" and "PSQI #5 Sleep disturbances" were related to thinning of the right lateral temporal cortex, with lower quality and more disturbances being associated with faster thinning. The association with "PSQI #5 Sleep disturbances" emerged after 60 years, especially in regions with high expression of genes related to oligodendrocytes and S1 pyramidal neurons. None of the sleep scales were related to a longitudinal change in episodic memory function, suggesting that sleep-related cortical changes were independent of cognitive decline. The relationship to cortical brain change suggests that self-reported sleep parameters are relevant in lifespan studies, but small effect sizes indicate that self-reported sleep is not a good biomarker of general cortical degeneration in healthy older adults.
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| 19. |
- Fjell, Anders M., et al.
(författare)
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Self-reported sleep relates to hippocampal atrophy across the adult lifespan : results from the Lifebrain consortium
- 2020
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Ingår i: Sleep. - : Oxford University Press. - 0161-8105 .- 1550-9109. ; 43:5
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: Poor sleep is associated with multiple age-related neurodegenerative and neuropsychiatric conditions. The hippocampus plays a special role in sleep and sleep-dependent cognition, and accelerated hippocampal atrophy is typically seen with higher age. Hence, it is critical to establish how the relationship between sleep and hippocampal volume loss unfolds across the adult lifespan.Methods: Self-reported sleep measures and MRI-derived hippocampal volumes were obtained from 3105 cognitively normal participants (18–90 years) from major European brain studies in the Lifebrain consortium. Hippocampal volume change was estimated from 5116 MRIs from 1299 participants for whom longitudinal MRIs were available, followed up to 11 years with a mean interval of 3.3 years. Cross-sectional analyses were repeated in a sample of 21,390 participants from the UK Biobank.Results: No cross-sectional sleep—hippocampal volume relationships were found. However, worse sleep quality, efficiency, problems, and daytime tiredness were related to greater hippocampal volume loss over time, with high scorers showing 0.22% greater annual loss than low scorers. The relationship between sleep and hippocampal atrophy did not vary across age. Simulations showed that the observed longitudinal effects were too small to be detected as age-interactions in the cross-sectional analyses.Conclusions: Worse self-reported sleep is associated with higher rates of hippocampal volume decline across the adult lifespan. This suggests that sleep is relevant to understand individual differences in hippocampal atrophy, but limited effect sizes call for cautious interpretation.
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| 20. |
- Fjell, Anders M., et al.
(författare)
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The genetic organization of longitudinal subcortical volumetric change is stable throughout the lifespan running title: Genetics of subcortical lifespan change
- 2021
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Ingår i: eLIFE. - : eLife Sciences Publications Ltd. - 2050-084X. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- Development and aging of the cerebral cortex show similar topographic organization and are governed by the same genes. It is unclear whether the same is true for subcortical regions, which follow fundamentally different ontogenetic and phylogenetic principles. We tested the hypothesis that genetically governed neurodevelopmental processes can be traced throughout life by assessing to which degree brain regions that develop together continue to change together through life. Analyzing over 6000 longitudinal MRIs of the brain, we used graph theory to identify five clusters of coordinated development, indexed as patterns of correlated volumetric change in brain structures. The clusters tended to follow placement along the cranial axis in embryonic brain development, suggesting continuity from prenatal stages, and correlated with cognition. Across independent longitudinal datasets, we demonstrated that developmental clusters were conserved through life. Twin-based genetic correlations revealed distinct sets of genes governing change in each cluster. Single nucleotide polymorphisms-based analyses of 38127 cross-sectional MRIs showed a similar pattern of genetic volume-volume correlations. In conclusion, coordination of subcortical change adheres to fundamental principles of lifespan continuity and genetic organization.
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