scholarly journals On the Impact of Interhemispheric White Matter: Age, Executive Functioning, and Dedifferentiation in the Frontal Lobes

2017 ◽  
Author(s):  
Abigail B. Waters ◽  
Kayle S. Sawyer ◽  
David A. Gansler
Keyword(s):  
Older Adults ◽  
White Matter ◽  
Executive Functioning ◽  
Significant Relationship ◽  
Grey Matter ◽  
Middle Age ◽  
Neural Substrates ◽  
Community Dwelling ◽  
Equation Modeling ◽  
Age Related

AbstractIntroductionIn middle age, declines in executive functioning (EF) are associated with decrements in the quality and/or quantity of white and grey matter. Recruitment of homologous regions has been identified as a compensatory mechanism for cognitive decline in later middle age, however research into neural substrates of EF has yet to be guided by dedifferentiation models. We hypothesized that frontal-parietal grey matter volume, interhemispheric white matter and intrahemispheric white matter fractional anisotropy (FA) will be predictive of EF. Further, we hypothesized that the comparative association between interhemispheric white matter and EF will increase with age, because of compensatory recruitment.MethodsNeurocognitive test data, DTI, and T1 MPRAGE scans (n = 444) were obtained from the NKI-Rockland Sample. Structural equation modeling was used to examine the relationship between age, EF, interhemispheric white matter (forceps minor; FM), intrahemispheric white matter (superior longitudinal fasciculus; SLF), and a frontal-parietal grey matter network. EF and grey matter were modelled as latent variables, with EF examined as the criterion. Additionally, a subsample of participants aged 55-85 (n = 168) was analyzed to examine the influence of age related compensatory mechanisms.ResultsThere was a significant relationship between FM, grey matter, and EF, which was fully mediated by age. There was a significant relationship between SLF and EF, which was not mediated by age. For older adults, only the age-mediated pathway from FM to EF was significant.DiscussionUsing structural imaging data, support was found for age-related interhemispheric mechanisms of compensation, but not intrahemispheric mechanisms.Key points(1) Neural substrates of executive functioning are not static across the lifespan. (2) In older adults, white matter becomes more salient as a structural correlate of executive functioning, as recruitment needs increase. (3) While the importance of interhemispheric white matter is mediated by age, intrahemispheric recruitment remains consistent across the lifespan, and is not the primary mechanism of age-based compensation in community dwelling older adults.

scholarly journals Age differentiation within grey matter, white matter and between memory and white matter in an adult lifespan cohort

2017 ◽  
Author(s):  
Susanne M. M. de Mooij ◽  
Richard N. A. Henson ◽  
Lourens J. Waldorp ◽  
Cam-CAN ◽  
Rogier A. Kievit
Keyword(s):  
White Matter ◽  
Cognitive Functions ◽  
Structural Equation ◽  
Grey Matter ◽  
Fluid Intelligence ◽  
Cognitive Factors ◽  
Equation Modeling ◽  
Grey Matter Volume ◽  
Adult Lifespan ◽  
Age Related

AbstractIt is well-established that brain structures and cognitive functions change across the lifespan. A longstanding hypothesis called age differentiation additionally posits that the relations between cognitive functions also change with age. To date however, evidence for age-related differentiation is mixed, and no study has examined differentiation of the relationship between brain and cognition. Here we use multi-group Structural Equation Modeling and SEM Trees to study differences within and between brain and cognition across the adult lifespan (18-88 years) in a large (N>646, closely matched across sexes), population-derived sample of healthy human adults from the Cambridge Centre for Ageing and Neuroscience (www.cam-can.org). After factor analyses of grey-matter volume (from T1- and T2-weighted MRI) and white-matter organisation (fractional anisotropy from Diffusion-weighted MRI), we found evidence for differentiation of grey and white matter, such that the covariance between brain factors decreased with age. However, we found no evidence for age differentiation between fluid intelligence, language and memory, suggesting a relatively stable covariance pattern between cognitive factors. Finally, we observed a specific pattern of age differentiation between brain and cognitive factors, such that a white matter factor, which loaded most strongly on the hippocampal cingulum, became less correlated with memory performance in later life. These patterns are compatible with reorganization of cognitive functions in the face of neural decline, and/or with the emergence of specific subpopulations in old age.Significance statementThe theory of age differentiation posits age-related changes in the relationships between cognitive domains, either weakening (differentiation) or strengthening (de-differentiation), but evidence for this hypothesis is mixed. Using age-varying covariance models in a large cross-sectional adult lifespan sample, we found age-related reductions in the covariance among both brain measures (neural differentiation), but no covariance change between cognitive factors of fluid intelligence, language and memory. We also observed evidence of uncoupling (differentiation) between a white matter factor and cognitive factors in older age, most strongly for memory. Together, our findings support age-related differentiation as a complex, multifaceted pattern that differs for brain and cognition, and discuss several mechanisms that might explain the changing relationship between brain and cognition.

scholarly journals The Effects of Lutein and Zeaxanthin Supplementation on Brain Morphology in Older Adults: A Randomized, Controlled Trial

2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Catherine M. Mewborn ◽  
Cutter A. Lindbergh ◽  
B. Randy Hammond ◽  
Lisa M. Renzi-Hammond ◽  
L. Stephen Miller
Keyword(s):  
Older Adults ◽  
Placebo Group ◽  
White Matter ◽  
Controlled Trial ◽  
Community Dwelling ◽  
Brain Morphology ◽  
Age Related ◽  
Supplement Group ◽  
One Year ◽  
Structural Brain

A growing literature emphasizes the importance of lifestyle factors such as nutrition in successful aging. The current study examined if one year of supplementation with lutein (L) and zeaxanthin (Z), two nutrients with known antioxidative properties and cognitive benefits, impacted structural brain outcomes in older adults using a double-blind, randomized, placebo-controlled trial design. Community-dwelling older adults (20 males and 27 females) aged 65–87 years (M = 71.8 years, SD = 6.04 years) were randomized into supplement (N = 33) and placebo groups (N = 14) using simple randomization. The supplement group received 10 mg L + 2 mg Z daily for 12 months while the placebo group received a visually identical, inert placebo. L and Z were measured via retinal concentrations (macular pigment optical density or MPOD). Structural brain outcomes, focusing on global and frontal-temporal lobe regions, were acquired using both T1-weighted and DTI MRI sequences. We hypothesized that the supplement group would increase, maintain, or show attenuated loss in hypothesized regions-of-interest (ROIs) while the placebo group would show age-related declines in brain structural integrity over the course of the trial. While results showed age-related declines for frontal and temporal gray and white matter volumes, as well as fornix white matter microstructure across both groups, only minimal differences were found between the supplement and placebo groups. However, exploratory analyses showed that individuals who responded better to supplementation (i.e., showed greater increases in MPOD) showed less decline in global and prefrontal gray matter volume than supplement “nonresponders.” While results suggest that one year of L and Z supplementation may have limited effects on structural brain outcomes overall, there may be a subsample of individuals for whom supplementation of L and Z provides greater benefits. ClinicalTrials.gov number, NCT02023645.

Sleep Mediates Age-Related Executive Function for Older Adults with Limited Cognitive Reserve

2020 ◽  
pp. 1-11
Author(s):  
Denise Parker ◽  
Romola S. Bucks ◽  
Stephanie R. Rainey-Smith ◽  
Erica Hodgson ◽  
Lara Fine ◽  
...  
Keyword(s):  
Older Adults ◽  
Executive Function ◽  
Structural Equation ◽  
Cognitive Reserve ◽  
Experimental Studies ◽  
Community Dwelling ◽  
Equation Modeling ◽  
Sleep Quantity ◽  
Age Related ◽  
The Impact

Abstract Objective: Sleep quantity and quality are associated with executive function (EF) in experimental studies, and in individuals with sleep disorders. With advancing age, sleep quantity and quality decline, as does the ability to perform EF tasks, suggesting that sleep disruption may contribute to age-related EF declines. This cross-sectional cohort study tested the hypothesis that poorer sleep quality (i.e., the frequency and duration of awakenings) and/or quantity may partly account for age-related EF deficits. Method: Community-dwelling older adults (N = 184) completed actigraphic sleep monitoring then a range of EF tasks. Two EF factors were extracted using exploratory structural equation modeling. Sleep variables did not mediate the relationship between age and EF factors. Post hoc moderated mediation analyses were conducted to test whether cognitive reserve compensates for sleep-related EF deficits, using years of education as a proxy measure of cognitive reserve. Results: We found a significant interaction between cognitive reserve and the number and frequency of awakenings, explaining a small (approximately 3%), but significant amount of variance in EF. Specifically, in individuals with fewer than 11 years of education, greater sleep disturbance was associated with poorer EF, but sleep did not impact EF in those with more education. There was no association between age and sleep quantity. Conclusions: This study highlights the role of cognitive reserve in the sleep–EF relationship, suggesting individuals with greater cognitive reserve may be able to counter the impact of disturbed sleep on EF. Therefore, improving sleep may confer some protection against EF deficits in vulnerable older adults.

scholarly journals Hippocampal subfields and limbic white matter jointly predict learning rate in older adults

2019 ◽  
Author(s):  
Andrew R. Bender ◽  
Andreas M. Brandmaier ◽  
Sandra Düzel ◽  
Attila Keresztes ◽  
Ofer Pasternak ◽  
...  
Keyword(s):  
Older Adults ◽  
White Matter ◽  
Structural Equation ◽  
Structural Characteristics ◽  
Verbal Learning ◽  
Learning Rate ◽  
Equation Modeling ◽  
Cerebral White Matter ◽  
Fiber Tractography ◽  
Age Related

AbstractAge-related memory impairments have been linked to differences in structural brain parameters, including cerebral white matter (WM) microstructure and hippocampal (HC) volume, but their combined influences are rarely investigated. In a population-based sample of 337 older participants 61–82 years of age (Mage=69.66, SDage=3.92 years) we modeled the independent and joint effects of limbic WM microstructure and HC subfield volumes on verbal learning. Participants completed a verbal learning task over five learning trials and underwent magnetic resonance imaging (MRI), including structural and diffusion scans. We segmented three HC subregions on high-resolution MRI data and sampled mean fractional anisotropy (FA) from bilateral limbic WM tracts identified via deterministic fiber tractography. Using structural equation modeling, we evaluated the associations between learning rate and latent factors representing FA sampled from limbic WM tracts, and HC subfield volumes, as well as their latent interaction. Results showed limbic WM and the interaction of HC and WM – but not HC volume alone – predicted verbal learning rates. Model decomposition revealed HC volume is only positively associated with learning rate in individuals with higher levels of WM anisotropy. We conclude that structural characteristics of limbic WM regions and HC volume jointly contribute to verbal learning in older adults.

scholarly journals Age-Related Patterns in the Subjective Appraisal of Cognition

2020 ◽  
Vol 4 (Supplement_1) ◽  
pp. 361-361
Author(s):  
Claudia Jacova ◽  
Samantha Smith ◽  
Frank Robertson
Keyword(s):  
Older Adults ◽  
Executive Functioning ◽  
Cognitive Decline ◽  
Community Dwelling ◽  
Subjective Cognitive Decline ◽  
Age Group ◽  
Everyday Functioning ◽  
Age Related ◽  
Cognitive Problems ◽  
The Relationship

Abstract Subjective cognitive decline (SCD) is a construct of high interest in aging and dementia because individuals endorsing it are at higher risk of developing cognitive problems. It is unclear how individuals arrive at the judgement that they have SCD. Here we aimed to understand which SCD symptoms give rise to the perception of decline as older adults age. Community-dwelling adults (N=494, mean age=63.6, SD=5.44), completed the Subjective Cognitive Decline Questionnaire (SCD-Q) online, using an online crowdsourcing site. The SCD-Q consists of one global question regarding self-perceived decline (yes/no) and 24 questions about everyday functioning which we utilized to form a memory, language, and executive functioning domain score, higher for greater perceived decline. Logistic regression revealed that memory and language domains predicted the likelihood of endorsing SCD for adults aged >64 (Memory: OR=1.76, CI=1.47-2.05; Language: OR=1.66, CI=1.30-2.02). Only the memory domain predicted the likelihood of endorsing SCD for adults <63 (OR=2.69, CI=2.35-3.02). Executive functioning domain scores did not play a role in the relationship between SCD likelihood in either age group. The higher the self-perceived memory or language decline, the more likely older adults are to conclude they have SCD. Our results suggest there is an age-related trajectory in how people evaluate their cognition, with younger people only considering memory and older people considering both memory and language. Clinicians should be aware of this trajectory when examining patients with SCD. Executive functions should be specifically queried because they may not emerge from older adults’ self-reported cognitive problems.

scholarly journals Hippocampal Subfields and Limbic White Matter Jointly Predict Learning Rate in Older Adults

2019 ◽  
Vol 30 (4) ◽  
pp. 2465-2477 ◽  
Author(s):  
Andrew R Bender ◽  
Andreas M Brandmaier ◽  
Sandra Düzel ◽  
Attila Keresztes ◽  
Ofer Pasternak ◽  
...  
Keyword(s):  
Older Adults ◽  
White Matter ◽  
Structural Equation ◽  
Structural Characteristics ◽  
Verbal Learning ◽  
Learning Rate ◽  
Equation Modeling ◽  
Cerebral White Matter ◽  
Fiber Tractography ◽  
Age Related

Abstract Age-related memory impairments have been linked to differences in structural brain parameters, including cerebral white matter (WM) microstructure and hippocampal (HC) volume, but their combined influences are rarely investigated. In a population-based sample of 337 older participants aged 61–82 years (Mage = 69.66, SDage = 3.92 years), we modeled the independent and joint effects of limbic WM microstructure and HC subfield volumes on verbal learning. Participants completed a verbal learning task of recall over five repeated trials and underwent magnetic resonance imaging (MRI), including structural and diffusion scans. We segmented three HC subregions on high-resolution MRI data and sampled mean fractional anisotropy (FA) from bilateral limbic WM tracts identified via deterministic fiber tractography. Using structural equation modeling, we evaluated the associations between learning rate and latent factors representing FA sampled from limbic WM tracts, and HC subfield volumes, and their latent interaction. Results showed limbic WM and the interaction of HC and WM—but not HC volume alone—predicted verbal learning rates. Model decomposition revealed HC volume is only positively associated with learning rate in individuals with higher WM anisotropy. We conclude that the structural characteristics of limbic WM regions and HC volume jointly contribute to verbal learning in older adults.

scholarly journals Spontaneous Eye Blinks Predict Executive Functioning in Seniors

2021 ◽  
Author(s):  
Jessika I. V. Buitenweg ◽  
Jaap M. J. Murre ◽  
K. Richard Ridderinkhof
Keyword(s):  
Older Adults ◽  
Working Memory ◽  
Executive Functioning ◽  
Cognitive Training ◽  
Functional Decline ◽  
Future Research ◽  
Blink Rate ◽  
Memory Updating ◽  
Age Related ◽  
Working Memory Updating

AbstractAs the world’s population is aging rapidly, cognitive training is an extensively used approach to attempt improvement of age-related cognitive functioning. With increasing numbers of older adults required to remain in the workforce, it is important to be able to reliably predict future functional decline, as well as the individual advantages of cognitive training. Given the correlation between age-related decline and striatal dopaminergic function, we investigated whether eye blink rate (EBR), a non-invasive, indirect indicator of dopaminergic activity, could predict executive functioning (response inhibition, switching and working memory updating) as well as trainability of executive functioning in older adults. EBR was collected before and after a cognitive flexibility training, cognitive training without flexibility, or a mock training. EBR predicted working memory updating performance on two measures of updating, as well as trainability of working memory updating, whereas performance and trainability in inhibition and switching tasks could not be predicted by EBR. Our findings tentatively indicate that EBR permits prediction of working memory performance in older adults. To fully interpret the relationship with executive functioning, we suggest future research should assess both EBR and dopamine receptor availability among seniors.

scholarly journals Coping Capacity and Episodic Memory in Older Adults With SMCs: The Mediating Role of Healthy Lifestyle

2020 ◽  
Vol 4 (Supplement_1) ◽  
pp. 278-279
Author(s):  
Feilong Wang ◽  
Shijie Li ◽  
Kaifa Wang ◽  
Yanni Yang
Keyword(s):  
Older Adults ◽  
Episodic Memory ◽  
Healthy Lifestyle ◽  
Community Dwelling ◽  
Mediating Effect ◽  
Equation Modeling ◽  
Coping Capacity ◽  
Memory Decline ◽  
Mediating Role

Abstract Older adults with subjective memory complaints (SMCs) are at increased risk for episodic memory decline. Episodic memory decline is an important predictor of objective memory impairment (one of the earliest symptoms of Alzheimer’s disease) and an often-suggested criterion of successful memory aging. Therefore, it is important to explore the determinant factors that influence episodic memory in older adults with SMCs. Roy adaptation model and preliminary evidence suggest that older adults with SMCs undergo a coping and adaptation process, a process influenced by many health-related risks and protective factors. This study aimed to explore the relationship between coping capacity and episodic memory, and the mediating role of healthy lifestyle between coping capacity and episodic memory in a sample of 309 community-dwelling older adults with SMCs. Results from the structural equation modeling showed that coping capacity directly affects episodic memory (r=0.629, p＜0.001), and there is a partial mediating effect (60.5%) of healthy lifestyle among this sample of older adults with SMCs. This study demonstrates that coping capacity and adaptation positively correlate with episodic memory in older adults with SMCs, and that these correlations are mediated by healthy lifestyle. The results suggest that older adults with poor coping capacity should be assessed and monitored regularly, and clear lifestyle-related interventions initiated by healthcare providers that promote healthy lifestyles may effectively improve coping capacity and episodic memory in this population group. Note: First author: Feilong Wang, Co-first author: Shijie li, Corresponding author: Yanni Yang

scholarly journals White matter correlates of scam susceptibility in community-dwelling older adults

2019 ◽  
Vol 14 (5) ◽  
pp. 1521-1530 ◽  
Author(s):  
Melissa Lamar ◽  
Konstantinos Arfanakis ◽  
Lei Yu ◽  
Shengwei Zhang ◽  
S. Duke Han ◽  
...  
Keyword(s):  
Older Adults ◽  
White Matter ◽  
Community Dwelling ◽  
Community Dwelling Older Adults
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