| 1. |
- Gellersen, Helena M., et al.
(författare)
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Medial temporal lobe structure, mnemonic and perceptual discrimination in healthy older adults and those at risk for mild cognitive impairment
- 2023
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Ingår i: Neurobiology of Aging. - : Elsevier BV. - 0197-4580 .- 1558-1497. ; 122, s. 88-106
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Tidskriftsartikel (refereegranskat)abstract
- Cognitive tests sensitive to the integrity of the medial temporal lobe (MTL), such as mnemonic discrimination of perceptually similar stimuli, may be useful early markers of risk for cognitive decline in older populations. Perceptual discrimination of stimuli with overlapping features also relies on MTL but remains relatively unexplored in this context. We assessed mnemonic discrimination in two test formats (Forced Choice, Yes/No) and perceptual discrimination of objects and scenes in 111 community-dwelling older adults at different risk status for cognitive impairment based on neuropsychological screening. We also investigated associations between performance and MTL sub-region volume and thickness. The at-risk group exhibited reduced entorhinal thickness and impaired perceptual and mnemonic discrimination. Perceptual discrimination impairment partially explained group differences in mnemonic discrimination and correlated with entorhinal thickness. Executive dysfunction accounted for Yes/No deficits in at-risk adults, demonstrating the importance of test format for the interpretation of memory decline. These results suggest that perceptual discrimination tasks may be useful tools for detecting incipient cognitive impairment related to reduced MTL integrity in nonclinical populations.
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| 2. |
- Johansson, Jarkko, et al.
(författare)
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Biphasic patterns of age-related differences in dopamine D1 receptors across the adult lifespan
- 2023
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Ingår i: Cell Reports. - 2211-1247. ; 42:9
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Tidskriftsartikel (refereegranskat)abstract
- Age-related alterations in D1-like dopamine receptor (D1DR) have distinct implications for human cognition and behavior during development and aging, but the timing of these periods remains undefined. Enabled by a large sample of in vivo assessments (n = 180, age 20 to 80 years of age, 50% female), we discover that age-related D1DR differences pivot at approximately 40 years of age in several brain regions. Focusing on the most age-sensitive dopamine-rich region, we observe opposing pre- and post-forties interrelations among caudate D1DR, cortico-striatal functional connectivity, and memory. Finally, particularly caudate D1DR differences in midlife and beyond, but not in early adulthood, associate with manifestation of white matter lesions. The present results support a model by which excessive dopamine modulation in early adulthood and insufficient modulation in aging are deleterious to brain function and cognition, thus challenging a prevailing view of monotonic D1DR function across the adult lifespan.
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| 3. |
- Korkki, Saana M., et al.
(författare)
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Fronto-striatal dopamine D2 receptor availability is associated with cognitive variability in older individuals with low dopamine integrity
- 2021
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- Within-person, moment-to-moment, variability in behavior increases with advancing adult age, potentially reflecting the influence of reduced structural and neurochemical brain integrity, especially that of the dopaminergic system. We examined the role of dopamine D2 receptor (D2DR) availability, grey-, and white-matter integrity, for between-person differences in cognitive variability in a large sample of healthy older adults (n = 181; 64–68years) from the Cognition, Brain, and Aging (COBRA) study. Intra-individual variability (IIV) in cognition was measured as across-trial variability in participants’ response times for tasks assessing perceptual speed and working memory, as well as for a control task of motor speed. Across the whole sample, no associations of D2DR availability, or grey- and white-matter integrity, to IIV were observed. However, within-person variability in cognition was increased in two subgroups of individuals displaying low mean-levelcognitive performance, one of which was characterized by low subcortical and cortical D2DR availability. In this latter group, fronto-striatal D2DR availability correlated negatively with within-person variability in cognition. This finding suggests that the influence of D2DR availability on cognitive variability may be more easily disclosed among individuals with low dopamine-system integrity, highlighting the benefits of large-scale studies for delineating heterogeneity in brain-behavior associations in older age.
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| 4. |
- Ngandu, Tiia, et al.
(författare)
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The effect of adherence on cognition in a multidomain lifestyle intervention (FINGER)
- 2022
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Ingår i: Alzheimer's & Dementia. - : John Wiley & Sons. - 1552-5260 .- 1552-5279. ; 18:7, s. 1325-1334
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Lifestyle interventions may prevent cognitive decline, but the sufficient dose of intervention activities and lifestyle changes is unknown. We investigated how intervention adherence affects cognition in the FINGER trial (pre-specified subgroup analyses).Methods: FINGER is a multicenter randomized controlled trial examining the efficacy of multidomain lifestyle intervention (ClinicalTrials.gov NCT01041989). A total of 1260 participants aged 60 to 77 with increased dementia risk were randomized to a lifestyle intervention and control groups. Percentage of completed intervention sessions, and change in multidomain lifestyle score (self-reported diet; physical, cognitive, and social activity; vascular risk) were examined in relation to change in Neuropsychological Test Battery (NTB) scores.Results: Active participation was associated with better trajectories in NTB total and all cognitive subdomains. Improvement in lifestyle was associated with improvement in NTB total and executive function.Discussion: Multidomain lifestyle changes are beneficial for cognitive functioning, but future interventions should be intensive enough, and supporting adherence is essential.
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