| 1. |
- Becker, Nina, et al.
(författare)
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Differential Effects of Encoding Instructions on Brain Activity Patterns of Item and Associative Memory
- 2017
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Ingår i: Journal of cognitive neuroscience. - : MIT Press - Journals. - 0898-929X .- 1530-8898. ; 29:3, s. 545-559
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Tidskriftsartikel (refereegranskat)abstract
- Evidence from neuroimaging studies suggests a critical role of hippocampus and inferior frontal gyrus (IFG) in associative relative to item encoding. Here, we investigated similarities and differences in functional brain correlates for associative and item memory as a function of encoding instruction. Participants received either incidental (animacy judgments) or intentional encoding instructions while fMRI was employed during the encoding of associations and items. In a subsequent recognition task, memory performance of participants receiving intentional encoding instructions was higher compared with those receiving incidental encoding instructions. Furthermore, participants remembered more items than associations, regardless of encoding instruction. Greater brain activation in the left anterior hippocampus was observed for intentionally compared with incidentally encoded associations, although activity in this region was not modulated by the type of instruction for encoded items. Furthermore, greater activity in the left anterior hippocampus and left IFG was observed during intentional associative compared with item encoding. The same regions were related to subsequent memory of intentionally encoded associations and were thus task relevant. Similarly, connectivity of the anterior hippocampus to the right superior temporal lobe and IFG was uniquely linked to subsequent memory of intentionally encoded associations. Our study demonstrates the differential involvement of anterior hippocampus in intentional relative to incidental associative encoding. This finding likely reflects that the intent to remember triggers a specific binding process accomplished by this region.
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| 2. |
- Becker, Nina, et al.
(författare)
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Structural brain correlates of associative memory in older adults
- 2015
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Ingår i: NeuroImage. - : Elsevier BV. - 1053-8119 .- 1095-9572. ; 118, s. 146-153
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Tidskriftsartikel (refereegranskat)abstract
- Associative memory involves binding two or more items into a coherent memory episode. Relative to memory for single items, associative memory declines greatly in aging. However, older individuals vary substantially in their ability to memorize associative information. Although functional studies link associative memory to the medial temporal lobe (MTL) and prefrontal cortex (PFC), little is known about how volumetric differences in MTL and PFC might contribute to individual differences in associative memory. We investigated regional gray-matter volumes related to individual differences in associative memory in a sample of healthy older adults (n = 54; age = 60 years). To differentiate item from associative memory, participants intentionally learned face-scene picture pairs before performing a recognition task that included single faces, scenes, and face-scene pairs. Gray-matter volumes were analyzed using voxel-based morphometry region-of-interest (ROI) analyses. To examine volumetric differences specifically for associative memory, item memory was controlled for in the analyses. Behavioral results revealed large variability in associative memory that mainly originated from differences in false-alarm rates. Moreover, associative memory was independent of individuals' ability to remember single items. Older adults with better associative memory showed larger gray-matter volumes primarily in regions of the left and right lateral PFC. These findings provide evidence for the importance of PFC in intentional learning of associations, likely because of its involvement in organizational and strategic processes that distinguish older adults with good from those with poor associative memory.
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| 3. |
- Becker, Nina, et al.
(författare)
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Structure-function associations of successful associative encoding
- 2019
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Ingår i: NeuroImage. - : Elsevier. - 1053-8119 .- 1095-9572. ; 201
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Tidskriftsartikel (refereegranskat)abstract
- Functional magnetic resonance imaging (MRI) studies have demonstrated a critical role of hippocampus and inferior frontal gyrus (IFG) in associative memory. Similarly, evidence from structural MRI studies suggests a relationship between gray-matter volume in these regions and associative memory. However, how brain volume and activity relate to each other during associative-memory formation remains unclear. Here, we used joint independent component analysis (jICA) to examine how gray-matter volume and brain activity would be associated during associative encoding, especially in medial-temporal lobe (MTL) and IFG. T1-weighted images were collected from 27 young adults, and functional MRI was employed during intentional encoding of object pairs. A subsequent recognition task tested participants' memory performance. Unimodal analyses using voxel-based morphometry revealed that participants with better associative memory showed larger gray-matter volume in left anterior hippocampus. Results from the jICA revealed one component that comprised a covariance pattern between gray-matter volume in anterior and posterior MTL and encoding-related activity in IFG. Our findings suggest that gray matter within the MTL modulates distally distinct parts of the associative encoding circuit, and extend previous studies that demonstrated MTL-IFG functional connectivity during associative memory tasks.
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| 4. |
- Brehmer, Yvonne, et al.
(författare)
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Plasticity of brain and cognition in older adults
- 2014
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Ingår i: Psychological Research. - : Springer Science and Business Media LLC. - 0340-0727 .- 1430-2772. ; 78:6, s. 790-802
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Forskningsöversikt (refereegranskat)abstract
- Aging is typically related to changes in brain and cognition, but the aging process is heterogeneous and differs between individuals. Recent research has started investigating the influence of cognitive and physical training on cognitive performance, functional brain activity, and brain structure in old age. The functional relevance of neural changes and the interactions among these changes following interventions is still a matter of debate. Here we selectively review research on structural and functional brain correlates of training-induced performance changes in healthy older adults and present exemplary longitudinal intervention studies sorted by the type of training applied (i.e., strategy-based training, process-specific training, and physical exercise). Although many training studies have been conducted recently, within each task domain, the number of studies that used comparable methods and techniques to assess behavioral and neural changes is limited. We suggest that future studies should include a multimodal approach to enhance the understanding of the relation between different levels of brain changes in aging and those changes that result from training. Investigating inter-individual differences in intervention-induced behavioral and neuronal changes would provide more information about who would benefit from a specific intervention and why. In addition, a more systematic examination of the time course of training-related structural and functional changes would improve the current level of knowledge about how learning is implemented in the brain and facilitate our understanding of contradictory results.
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| 5. |
- Ding, Mozhu, et al.
(författare)
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Cerebral Small Vessel Disease Associated With Atrial Fibrillation Among Older Adults : A Population-Based Study.
- 2021
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Ingår i: Stroke. - : American Heart Association. - 0039-2499 .- 1524-4628. ; 52:8, s. 2685-2689
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND AND PURPOSE: Cerebral small vessel disease, as a potential mechanism underlying the association between atrial fibrillation (AF) and dementia, remains poorly investigated. In this cohort study, we sought to examine the association between AF and cerebral small vessel disease markers among older adults.METHODS: Data on 336 participants (age ≥60 years, mean 70.2 years; 60.2% women) free of dementia, disability, and cerebral infarcts were derived from the population-based Swedish National Study on Aging and Care in Kungsholmen. Structural brain magnetic resonance imaging examinations were performed at baseline (2001-2004) and follow-ups (2004-2007 and 2007-2010). Magnetic resonance imaging markers of cerebral small vessel disease included perivascular spaces, lacunes, and volumes of white matter hyperintensities, lateral ventricles, and total brain tissue. AF was assessed at baseline and follow-ups through clinical examinations, electrocardiogram, and medical records. Data were analyzed using linear mixed-effects models.RESULTS: At baseline, 18 persons (5.4%) were identified to have prevalent AF and 17 (5.6%) developed incident AF over the 6-year follow-up. After multivariable adjustment, AF was significantly associated with a faster annual increase in white matter hyperintensities volume (β coefficient=0.45 [95% CI, 0.04-0.86]) and lateral ventricular volume (0.58 [0.13-1.02]). There was no significant association of AF with annual changes in perivascular spaces number (β coefficient=0.53 [95% CI, -0.27 to 1.34]) or lacune number (-0.01 [-0.07 to 0.05]).CONCLUSIONS: Independent of cerebral infarcts, AF is associated with accelerated progression of white matter lesions and ventricular enlargement among older adults.
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| 6. |
- 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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| 7. |
- Dong, Yi, et al.
(författare)
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Anosmia, mild cognitive impairment, and biomarkers of brain aging in older adults
- 2023
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Ingår i: Alzheimer's & Dementia. - : Wiley. - 1552-5260 .- 1552-5279. ; 19:2, s. 589-601
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Tidskriftsartikel (refereegranskat)abstract
- Olfactory impairment is a potential marker for prodromal dementia, but the underlying mechanisms are poorly understood. This population-based study included 4214 dementia-free participants (age ≥65 years). Olfaction was assessed using the 16-item Sniffin’ Sticks identification test. In the subsamples, we measured plasma amyloid beta (Aβ)40, Aβ42, total tau, and neurofilament light chain (NfL; n = 1054); and quantified hippocampal, entorhinal cortex, and white matter hyperintensity (WMH) volumes, and Alzheimer's disease (AD)-signature cortical thickness (n = 917). Data were analyzed with logistic and linear regression models. In the total sample, mild cognitive impairment (MCI) was diagnosed in 1102 persons (26.2%; amnestic MCI, n = 931; non-amnestic MCI, n = 171). Olfactory impairment was significantly associated with increased likelihoods of MCI, amnestic MCI, and non-amnestic MCI. In the subsamples, anosmia was significantly associated with higher plasma total tau and NfL concentrations, smaller hippocampal and entorhinal cortex volumes, and greater WMH volume, and marginally with lower AD-signature cortical thickness. These results suggest that cerebral neurodegenerative and microvascular lesions are common neuropathologies linking anosmia with MCI in older adults.
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| 8. |
- Eriksson, Johan, et al.
(författare)
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Rewiring the brain with repeated retrieval : A parametric fMRI study of the testing effect
- 2011
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Ingår i: Neuroscience Letters. - Amsterdam : Elsevier BV. - 0304-3940 .- 1872-7972. ; 505:1, s. 36-40
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Tidskriftsartikel (refereegranskat)abstract
- The "testing effect" refers to the beneficial effects on memory performance from being tested, a phenomenon of potentially substantial implications in educational settings. While the effect itself is firmly established in previous research, little is known of related brain changes. Here we used fMRI and a parametric design to show that repeated successful retrieval during a memory acquisition phase leads to higher brain activity in the anterior cingulate cortex (ACC) at a subsequent test phase. The extent of ACC activity increase correlated across individuals with memory performance 5 months later. In relation to recent research that associates the ACC with memory consolidation processes, the present results suggest that the testing effect may operate at the systems level by enhancing consolidation of memory representations.
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| 9. |
- Ferencz, Beata, et al.
(författare)
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Promising Genetic Biomarkers of Preclinical Alzheimer's Disease : The Influence of APOE and TOMM40 on Brain Integrity
- 2012
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Ingår i: International Journal of Alzheimer's Disease. - : Hindawi Limited. - 2090-8024 .- 2090-0252. ; 2012
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Forskningsöversikt (refereegranskat)abstract
- Finding biomarkers constitutes a crucial step for early detection of Alzheimer's disease (AD). Brain imaging techniques have revealed structural alterations in the brain that may be phenotypic in preclinical AD. The most prominent polymorphism that has been associated with AD and related neural changes is the Apolipoprotein E (APOE) ε4. The translocase of outer mitochondrial membrane 40 (TOMM40), which is in linkage disequilibrium with APOE, has received increasing attention as a promising gene in AD. TOMM40 also impacts brain areas vulnerable in AD, by downstream apoptotic processes that forego extracellular amyloid beta aggregation. The present paper aims to extend on the mitochondrial influence in AD pathogenesis and we propose a TOMM40-induced disconnection of the medial temporal lobe. Finally, we discuss the possibility of mitochondrial dysfunction being the earliest pathophysiological event in AD, which indeed is supported by recent findings.
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| 10. |
- Ferencz, Beata, et al.
(författare)
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The Benefits of Staying Active in Old Age : Physical Activity Counteracts the Negative Influence of PICALM, BIN1, and CLU Risk Alleles on Episodic Memory Functioning
- 2014
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Ingår i: Psychology and Aging. - : American Psychological Association (APA). - 0882-7974 .- 1939-1498. ; 29:2, s. 440-449
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Tidskriftsartikel (refereegranskat)abstract
- PICALM, BIN1, CLU, and APOE are top candidate genes for Alzheimer's disease, and they influence episodic memory performance in old age. Physical activity, however, has been shown to protect against age-related decline and counteract genetic influences on cognition. The aims of this study were to assess whether (a) a genetic risk constellation of PICALM, BIN1, and CLU polymorphisms influences cognitive performance in old age; and (b) if physical activity moderates this effect. Data from the SNAC-K population-based study were used, including 2,480 individuals (age range = 60 to 100 years) free of dementia at baseline and at 3- to 6-year follow-ups. Tasks assessing episodic memory, perceptual speed, knowledge, and verbal fluency were administered. Physical activity was measured using self-reports. Individuals who had engaged in frequent health-or fitness-enhancing activities within the past year were compared with those who were inactive. Genetic risk scores were computed based on an integration of risk alleles for PICALM (rs3851179 G allele, rs541458 T allele), BIN1 (rs744373 G allele), and CLU (rs11136000 T allele). High genetic risk was associated with reduced episodic memory performance, controlling for age, education, vascular risk factors, chronic diseases, activities of daily living, and APOE gene status. Critically, physical activity attenuated the effects of genetic risk on episodic memory. Our findings suggest that participants with high genetic risk who maintain a physically active lifestyle show selective benefits in episodic memory performance.
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