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Träfflista för sökning "WFRF:(Lindenberger Ulman) ;pers:(Preuschhof Claudia)"

Sökning: WFRF:(Lindenberger Ulman) > Preuschhof Claudia

  • Resultat 1-7 av 7
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1.
  • Burzynska, Agnieszka Z., et al. (författare)
  • A Scaffold for Efficiency in the Human Brain
  • 2013
  • Ingår i: Journal of Neuroscience. - 0270-6474 .- 1529-2401. ; 33:43, s. 17150-17159
  • Tidskriftsartikel (refereegranskat)abstract
    • The comprehensive relations between healthy adult human brain white matter(WM) microstructure and gray matter (GM) function, and their joint relations to cognitive performance, remain poorly understood. We investigated these associations in 27 younger and 28 older healthy adults by linking diffusion tensor imaging (DTI) with functional magnetic resonance imaging (fMRI) data collected during an n-back working memory task. We present a novel application of multivariate Partial Least Squares (PLS) analysis that permitted the simultaneous modeling of relations between WM integrity values from all major WM tracts and patterns of condition-related BOLD signal across all GM regions. Our results indicate that greater microstructural integrity of the major WM tracts was negatively related to condition-related blood oxygenation level-dependent (BOLD) signal in task-positive GM regions. This negative relationship suggests that better quality of structural connections allows for more efficient use of task-related GM processing resources. Individuals with more intact WM further showed greater BOLD signal increases in typical task-negative regions during fixation, and notably exhibited a balanced magnitude of BOLD response across task-positive and-negative states. Structure-function relations also predicted task performance, including accuracy and speed of responding. Finally, structure-function behavior relations reflected individual differences over and above chronological age. Our findings provide evidence for the role of WM microstructure as a scaffold for the context-relevant utilization of GM regions.
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2.
  • Burzynska, Agnieszka Z., et al. (författare)
  • Cortical thickness is linked to executive functioning in adulthood and aging
  • 2012
  • Ingår i: Human Brain Mapping. - : Wiley. - 1065-9471 .- 1097-0193. ; 33:7, s. 1607-20
  • Tidskriftsartikel (refereegranskat)abstract
    • Executive functions that are dependent upon the frontal-parietal network decline considerably during the course of normal aging. To delineate neuroanatomical correlates of age-related executive impairment, we investigated the relation between cortical thickness and executive functioning in 73 younger (20-32 years) and 56 older (60-71 years) healthy adults. Executive functioning was assessed using the Wisconsin Card Sorting Test (WCST). Cortical thickness was measured at each location of the cortical mantle using surface-based segmentation procedures on high-resolution T1-weighted magnetic resonance images. For regions involved in WCST performance, such as the lateral prefrontal and parietal cortices, we found that thicker cortex was related to higher accuracy. Follow-up ROI-based analyses revealed that these associations were stronger in older than in younger adults. Moreover, among older adults, high and low performers differed in cortical thickness within regions generally linked to WCST performance. Our results indicate that the structural cortical correlates of executive functioning largely overlap with previously identified functional patterns. We conclude that structural preservation of relevant brain regions is associated with higher levels of executive performance in old age, and underscore the need to consider the heterogeneity of brain aging in relation to cognitive functioning.
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3.
  • Garrett, Douglas D., et al. (författare)
  • Amphetamine modulates brain signal variability and working memory in younger and older adults
  • 2015
  • Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 112:24, s. 7593-7598
  • Tidskriftsartikel (refereegranskat)abstract
    • Better-performing younger adults typically express greater brain signal variability relative to older, poorer performers. Mechanisms for age and performance-graded differences in brain dynamics have, however, not yet been uncovered. Given the age-related decline of the dopamine (DA) system in normal cognitive aging, DA neuromodulation is one plausible mechanism. Hence, agents that boost systemic DA [such as d-amphetamine (AMPH)] may help to restore deficient signal variability levels. Furthermore, despite the standard practice of counterbalancing drug session order (AMPH first vs. placebo first), it remains understudied how AMPH may interact with practice effects, possibly influencing whether DA up-regulation is functional. We examined the effects of AMPH on functional-MRI-based blood oxygen level-dependent (BOLD) signal variability (SDBOLD) in younger and older adults during a working memory task (letter n-back). Older adults expressed lower brain signal variability at placebo, but met or exceeded young adult SDBOLD levels in the presence of AMPH. Drug session order greatly moderated change-change relations between AMPH-driven SDBOLD and reaction time means (RTmean) and SDs (RTSD). Older adults who received AMPH in the first session tended to improve in RTmean and RTSD when SDBOLD was boosted on AMPH, whereas younger and older adults who received AMPH in the second session showed either a performance improvement when SDBOLD decreased (for RTmean) or no effect at all (for RTSD). The present findings support the hypothesis that age differences in brain signal variability reflect aging-induced changes in dopaminergic neuromodulation. The observed interactions among AMPH, age, and session order highlight the state-and practice-dependent neurochemical basis of human brain dynamics.
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4.
  • Li, Shu-Chen, et al. (författare)
  • Aging magnifies the effects of dopamine transporter and D2 receptor genes on backward serial memory
  • 2013
  • Ingår i: Neurobiology of Aging. - : Elsevier BV. - 0197-4580 .- 1558-1497. ; 34:1, s. 358.e1-358.e10
  • 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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5.
  • Nagel, Irene E, et al. (författare)
  • Load modulation of BOLD response and connectivity predicts working memory performance in younger and older adults
  • 2011
  • Ingår i: Journal of cognitive neuroscience. - Cambridge, Mass. : MIT Press. - 0898-929X .- 1530-8898. ; 23:8, s. 2030-2045
  • Tidskriftsartikel (refereegranskat)abstract
    • Individual differences in working memory (WM) performance have rarely been related to individual differences in the functional responsivity of the WM brain network. By neglecting person-to-person variation, comparisons of network activity between younger and older adults using functional imaging techniques often confound differences in activity with age trends in WM performance. Using functional magnetic resonance imaging, we investigated the relations among WM performance, neural activity in the WM network, and adult age using a parametric letter n-back task in 30 younger adults (21-31 years) and 30 older adults (60-71 years). Individual differences in the WM network's responsivity to increasing task difficulty were related to WM performance, with a more responsive BOLD signal predicting greater WM proficiency. Furthermore, individuals with higher WM performance showed greater change in connectivity between left dorsolateral prefrontal cortex and left premotor cortex across load. We conclude that a more responsive WM network contributes to higher WM performance, regardless of adult age. Our results support the notion that individual differences in WM performance are important to consider when studying the WM network, particularly in age-comparative studies.
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6.
  • Nagel, Irene E, et al. (författare)
  • Performance level modulates adult age differences in brain activation during spatial working memory.
  • 2009
  • Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 106:52, s. 22552-22557
  • Tidskriftsartikel (refereegranskat)abstract
    • Working memory (WM) shows pronounced age-related decline. Functional magnetic resonance imaging (fMRI) studies have revealed age differences in task-related brain activation. Evidence based primarily on episodic memory studies suggests that brain activation patterns can be modulated by task difficulty in both younger and older adults. In most fMRI aging studies on WM, however, performance level has not been considered, so that age differences in activation patterns are confounded with age differences in performance level. Here, we address this issue by comparing younger and older low and high performers in an event-related fMRI study. Thirty younger (20-30 years) and 30 older (60-70 years) healthy adults were tested with a spatial WM task with three load levels. A region-of-interest analysis revealed marked differences in the activation patterns between high and low performers in both age groups. Critically, among the older adults, a more "youth-like" load-dependent modulation of the blood oxygen level-dependent signal was associated with higher levels of spatial WM performance. These findings underscore the need of taking performance level into account when studying changes in functional brain activation patterns from early to late adulthood.
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7.
  • Preuschhof, Claudia, et al. (författare)
  • KIBRA and CLSTN2 polymorphisms exert interactive effects on human episodic memory
  • 2010
  • Ingår i: Neuropsychologia. - : Elsevier BV. - 0028-3932 .- 1873-3514. ; 48:2, s. 402-408
  • Tidskriftsartikel (refereegranskat)abstract
    • Individual differences in episodic memory are highly heritable. Several studies have linked a polymorphism in the gene encoding the KIBRA protein to episodic memory performance. Results regarding CLSTN2, the gene encoding the synaptic protein calsyntenin 2, have been less consistent, possibly pointing to interactions with other genes. Given that both KIBRA and CLSTN2 are expressed in the medial temporal lobe and have been linked to synaptic plasticity, we investigated whether KIBRA and CLSTN2 interactively modulate episodic memory performance (n=383). We replicated the beneficial effect of the KIBRA T-allele on episodic memory, and discovered that this effect increases with the associative demands of the memory task. Importantly, the memory-enhancing effect of the KIBRA T-allele was boosted by the presence of the CLSTN2 C-allele, which positively affected memory performance in some previous studies. In contrast, the presence of CLSTN2 C-allele led to reduced performance in subjects homozygous for the KIBRA C-allele. Overall, these findings suggest that KIBRA and CLSTN2 interactively modulate episodic memory performance, and underscore the need for delineating the interactive effects of multiple genes on brain and behavior.
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  • Resultat 1-7 av 7

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