| 1. |
- Lövdén, Martin, et al.
(författare)
-
Performance-Related Increases in Hippocampal N-acetylaspartate (NAA) Induced by Spatial Navigation Training Are Restricted to BDNF Val Homozygotes
- 2011
-
Ingår i: Cerebral Cortex. - : Oxford University Press (OUP). - 1460-2199 .- 1047-3211. ; 21:6, s. 1435-1442
-
Tidskriftsartikel (refereegranskat)abstract
- Recent evidence indicates experience-dependent brain volume changes in humans, but the functional and histological nature of such changes is unknown. Here, we report that adult men performing a cognitively demanding spatial navigation task every other day over 4 months display increases in hippocampal N-acetylaspartate (NAA) as measured with magnetic resonance spectroscopy. Unlike measures of brain volume, changes in NAA are sensitive to metabolic and functional aspects of neural and glia tissue and unlikely to reflect changes in microvasculature. Training-induced changes in NAA were, however, absent in carriers of the Met substitution in the brain-derived neurotrophic factor (BDNF) gene, which is known to reduce activity-dependent secretion of BDNF. Among BDNF Val homozygotes, increases in NAA were strongly related to the degree of practice-related improvement in navigation performance and normalized to pretraining levels 4 months after the last training session. We conclude that changes in demands on spatial navigation can alter hippocampal NAA concentrations, confirming epidemiological studies suggesting that mental experience may have direct effects on neural integrity and cognitive performance. BDNF genotype moderates these plastic changes, in line with the contention that gene-context interactions shape the ontogeny of complex phenotypes.
|
|
| 2. |
- Brehmer, Yvonne, et al.
(författare)
-
Plasticity of brain and cognition in older adults
- 2014
-
Ingår i: Psychological Research. - : Springer Science and Business Media LLC. - 0340-0727 .- 1430-2772. ; 78:6, s. 790-802
-
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.
|
|
| 3. |
- Brose, Annette, et al.
(författare)
-
Adult Age Differences in Covariation of Motivation and Working Memory Performance: Contrasting Between-Person and Within-Person Findings
- 2010
-
Ingår i: Research in Human Development. - : Informa UK Limited. - 1542-7609 .- 1542-7617. ; 7:1, s. 61-78
-
Tidskriftsartikel (refereegranskat)abstract
- Developmental theorists have proposed for a long time that the prevailing focus on stable individual differences has obstructed the discovery of short-term covariations between cognitive performance and contextual influences within individuals that may help to uncover mechanisms underlying long-term change. As an initial step to overcome this imbalance, we observed measures of motivation and working memory (WM) in 101 younger and 103 older adults across 100 occasions. Our main goals were to (1) investigate day-to-day relations between motivation and WM, (2) show that these relations differ between groups of younger and older adults, and (3) test whether the within-person and between-person structures linking motivational variables to WM are equivalent (i.e., the ergodicity assumption). The covariation between motivation and WM was generally positive in younger adults. In contrast, older adults showed reduced variability in motivation, increased variability across trials, and small reliability-adjusted correlations between motivation and WM. Within-person structures differed reliably across individuals, defying the ergodicity assumption. We discuss the implications of our findings for developmental theory and design, stressing the need to explore the effects of between-person differences in short-term covariations on long-term developmental change.
|
|
| 4. |
- Brose, Annette, et al.
(författare)
-
Daily variability in working memory is coupled with negative affect : the role of attention and motivation
- 2012
-
Ingår i: Emotion. - : American Psychological Association (APA). - 1528-3542 .- 1931-1516. ; 12:3, s. 605-617
-
Tidskriftsartikel (refereegranskat)abstract
- Across days, individuals experience varying levels of negative affect, control of attention, and motivation. We investigated whether this intraindividual variability was coupled with daily fluctuations in working memory (WM) performance. In 100 days, 101 younger individuals worked on a spatial N-back task and rated negative affect, control of attention, and motivation. Results showed that individuals differed in how reliably WM performance fluctuated across days, and that subjective experiences were primarily linked to performance accuracy. WM performance was lower on days with higher levels of negative affect, reduced control of attention, and reduced task-related motivation. Thus, variables that were found to predict WM in between-subjects designs showed important relationships to WM at the within-person level. In addition, there was shared predictive variance among predictors of WM. Days with increased negative affect and reduced performance were also days with reduced control of attention and reduced motivation to work on tasks. These findings are in line with proposed mechanisms linking negative affect and cognitive performance.
|
|
| 5. |
- Brose, Annette, et al.
(författare)
-
Normal aging dampens the link between intrusive thoughts and negative affect in reaction to daily stressors
- 2011
-
Ingår i: Psychology and aging. - Arlington, VA : American Psychological Association (APA). - 0882-7974 .- 1939-1498. ; 26:2, s. 488-502
-
Tidskriftsartikel (refereegranskat)abstract
- We charted daily variations in intrusive thoughts to gain access to adult age differences in affective reactivity to daily stressors. On 100 days, 101 younger and 103 older adults reported stressors, intrusive thoughts, and negative affect. Although increments in intrusive thoughts were similar in both age groups on days with stressors, older adults' negative affect increased less than younger adults' on such days. In addition, (a) levels of intrusive thoughts and negative affect across study time were positively associated; (b) days with increased thoughts were days with increased negative affect; and (c) experiencing above-average intrusive thoughts about stressors strengthened affective reactions to stress. Relative to younger adults, all three associations were reduced in older adults. We tentatively conclude that normal aging dampens the stress-induced link between intrusive thoughts and affect. This dampening may contribute to preserved affective well-being and reduced affective reactivity to daily stress in old age.
|
|
| 6. |
- Ferencz, Beata, et al.
(författare)
-
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
-
Ingår i: Psychology and Aging. - : American Psychological Association (APA). - 0882-7974 .- 1939-1498. ; 29:2, s. 440-449
-
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.
|
|
| 7. |
- Ferencz, Beata, et al.
(författare)
-
The influence of APOE and TOMM40 polymorphisms on hippocampal volume and episodic memory in old age
- 2013
-
Ingår i: Frontiers in Human Neuroscience. - : Frontiers Media SA. - 1662-5161. ; 7
-
Tidskriftsartikel (refereegranskat)abstract
- Mitochondrial dysfunction is implicated in neurodegenerative disorders, such as Alzheimer's disease (AD). Translocase of outer mitochondrial membrane 40 (TOMM40) may be influential in this regard by influencing mitochondrial neurotoxicity. Little is known about the influence of the TOMM40 gene on hippocampal (HC) volume and episodic memory (EM), particularly in healthy older adults. Thus, we sought to discern the influence of TOMM40 single nucleotide polymorphisms (SNPs), which have previously been associated with medial temporal lobe integrity (rs11556505 and rs2075650), on HC volume and EM. The study sample consisted of individuals from the Swedish National Study on Aging and Care in Kungsholmen (SNAC-K) who were free of dementia and known neurological disorders, and 6087 years of age (n = 424). EM was measured by using a 16-item word list with a 2-min free recall period and delineation of the HC was performed manually. The influence of Apolipoprotein E (APOE) and TOMM40 was assessed by 2 x 2 ANOVAs and partial correlations. There was no effect of APOE and TOMM40 on EM performance and HC volume. However, partial correlations revealed that HC volume was positively associated with free recall performance (r = 0.21, p < 0.01, r(2) = 0.04). When further stratified for TOMM40, the observed association between HC volume and free recall in APOE epsilon 4 carriers was present in combination with TOMM40 rs11556505 any T (r = 0.28, p < 0.01, R-2 = 0.08) and rs2075650 any G (r = 0.28, p < 0.01, R-2 = 0.08) risk alleles. This pattern might reflect higher reliance on HC volume for adequate EM performance among APOE epsilon 4 carriers with additional TOMM40 risk alleles suggesting that the TOMM40 gene cannot merely be considered a marker of APOE genotype. Nevertheless, neither APOE nor TOMM40 influenced HC volume or EM in this population-based sample of cognitively intact individuals over the age of 60.
|
|
| 8. |
- Grandy, Thomas H., et al.
(författare)
-
Individual alpha peak frequency is related to latent factors of general cognitive abilities
- 2013
-
Ingår i: NeuroImage. - : Elsevier BV. - 1053-8119 .- 1095-9572. ; 79, s. 10-18
-
Tidskriftsartikel (refereegranskat)abstract
- Some eighty years after the discovery of the human electroencephalogram (EEG) and its dominant rhythm, alpha (similar to 10 Hz), the neurophysiological functions and behavioral correlates of alpha oscillations are still under debate. Similarly, the biological mechanisms contributing to the general factor of intelligence, or g, have been under scrutiny for decades. Individual alpha frequency (IAF), a trait-like parameter of the EEG, has been found to correlate with individual differences in cognitive performance and cognitive abilities. Informed by large-scale theories of neural organization emphasizing the general functional significance of oscillatory activity, the present study replicates and extends these findings by testing the hypothesis that IAF is related to intelligence at the level of g, rather than at the level of specific cognitive abilities. Structural equation modeling allowed us to statistically control for measurement error when estimating the association between IAF and intellectual functioning. In line with our hypothesis, we found a statistically reliable and substantial correlation between IAF and g (r = .40). The magnitude of this correlation did not differ significantly between younger and older adults, and captured all of the covariation between IAF and the cognitive abilities of reasoning, memory, and perceptual speed. The observed association between IAF and g provides a parsimonious explanation for the commonly observed diffuse pattern of correlations between IAF and cognitive performance. We conclude that IAF is a marker of global architectural and functional properties of the human brain.
|
|
| 9. |
- Grandy, Thomas H., et al.
(författare)
-
Peak individual alpha frequency qualifies as a stable neurophysiological trait marker in healthy younger and older adults
- 2013
-
Ingår i: Psychophysiology. - : Wiley. - 0048-5772 .- 1469-8986 .- 1540-5958. ; 50:6, s. 570-582
-
Tidskriftsartikel (refereegranskat)abstract
- The individual alpha frequency (IAF) of the human EEG reflects systemic properties of the brain, is highly heritable, and relates to cognitive functioning. Not much is known about the modifiability of IAF by cognitive interventions. We report analyses of resting EEG from a large-scale training study in which healthy younger (2031 years, N=30) and older (6580 years, N=28) adults practiced 12 cognitive tasks for approximate to 100 1-h sessions. EEG was recorded before and after the cognitive training intervention. In both age groups, IAF (and, in a control analysis, alpha amplitude) did not change, despite large gains in cognitive performance. As within-session reliability and test-retest stability were high for both age groups, imprecise measurements cannot account for the findings. In sum, IAF is highly stable in healthy adults up to 80 years, not easily modifiable by cognitive interventions alone, and thus qualifies as a stable neurophysiological trait marker.
|
|
| 10. |
- Kühn, Simone, et al.
(författare)
-
Brain areas consistently linked to individual differences in perceptual decision-making in younger as well as older adults before and after training
- 2011
-
Ingår i: Journal of cognitive neuroscience. - Cambridge, Mass. : MIT Press. - 0898-929X .- 1530-8898. ; 23:9, s. 2147-2158
-
Tidskriftsartikel (refereegranskat)abstract
- Perceptual decision-making performance depends on several cognitive and neural processes. Here, we fit Ratcliff's diffusion model to accuracy data and reaction-time distributions from one numerical and one verbal two-choice perceptual-decision task to deconstruct these performance measures into the rate of evidence accumulation (i.e., drift rate), response criterion setting (i.e., boundary separation), and peripheral aspects of performance (i.e., nondecision time). These theoretical processes are then related to individual differences in brain activation by means of multiple regression. The sample consisted of 24 younger and 15 older adults performing the task in fMRI before and after 100 daily 1-hr behavioral training sessions in a multitude of cognitive tasks. Results showed that individual differences in boundary separation were related to striatal activity, whereas differences in drift rate were related to activity in the inferior parietal lobe. These associations were not significantly modified by adult age or perceptual expertise. We conclude that the striatum is involved in regulating response thresholds, whereas the inferior parietal lobe might represent decision-making evidence related to letters and numbers.
|
|
