scholarly journals Disrupted neural synchrony mediates the relationship between white matter integrity and cognitive performance in older adults

2019 ◽  
Author(s):  
T. Hinault ◽  
M. Kraut ◽  
A. Bakker ◽  
A. Dagher ◽  
S.M. Courtney

AbstractOur main goal was to determine the influence of white matter integrity on the dynamic coupling between brain regions and the individual variability of cognitive performance in older adults. EEG was recorded while participants performed a task specifically designed to engage working memory and inhibitory processes, and the associations among functional activity, structural integrity, and cognitive performance were assessed. We found that the association between white matter microstructural integrity and cognitive functioning with aging is mediated by time-varying alpha and gamma phase-locking value (PLV). Specifically, older individuals with better preservation of the inferior fronto-occipital fasciculus showed greater task-related modulations of alpha and gamma long-range PLV between the inferior frontal gyrus and occipital lobe, lower local phase-amplitude coupling in occipital lobes, and better cognitive control performance. Our results help delineate the role of individual variability of white matter microstructure in dynamic synchrony and cognitive performance during normal aging, and show that even small reductions in white matter integrity can lead to altered communications between brain regions, which in turn can result in reduced efficiency of cognitive functioning.Significance statementCognitive aging is associated with large individual differences, as some individuals maintain cognitive performance similar to that of young adults while others are significantly impaired. We hypothesized that individual differences in white matter integrity would influence the functional synchrony between frontal and posterior brain regions, and cognitive performance in older adults. We found that the association between reduced tract integrity and worse cognitive performance in older adults was mediated by task-related modulations of coupling synchrony in the alpha and gamma bands. Results offer a mechanistic explanation for the neural basis of the variability of cognitive performance in older adults who do not have any clinically diagnosable neuropathology, and for the association between structural network integrity and cognition in older adults.

2020 ◽  
Vol 30 (10) ◽  
pp. 5570-5582 ◽  
Author(s):  
T Hinault ◽  
M Kraut ◽  
A Bakker ◽  
A Dagher ◽  
S M Courtney

Abstract Our main goal was to determine the influence of white matter integrity on the dynamic coupling between brain regions and the individual variability of cognitive performance in older adults. Electroencephalography was recorded while participants performed a task specifically designed to engage working memory and inhibitory processes, and the associations among functional activity, structural integrity, and cognitive performance were assessed. We found that the association between white matter microstructural integrity and cognitive functioning with aging is mediated by time-varying alpha and gamma phase-locking value. Specifically, better preservation of the inferior fronto-occipital fasciculus in older individuals drives faster task-related modulations of alpha and gamma long-range phase-locking value between the inferior frontal gyrus and occipital lobe and lower local phase-amplitude coupling in occipital lobes, which in turn drives better cognitive control performance. Our results help delineate the role of individual variability of white matter microstructure in dynamic synchrony and cognitive performance during normal aging.


2021 ◽  
Vol 13 ◽  
Author(s):  
Stephanie Matijevic ◽  
Lee Ryan

Well-established literature indicates that older adults have poorer cerebral white matter integrity, as measured through diffusion tensor imaging (DTI). Age differences in DTI have been observed widely across white matter, although some tracts appear more sensitive to the effects of aging than others. Factors like APOE ε4 status and sex may contribute to individual differences in white matter integrity that also selectively impact certain tracts, and could influence DTI changes in aging. The present study explored the degree to which age, APOE ε4, and sex exerted global vs. tract specific effects on DTI metrics in cognitively healthy late middle-aged to older adults. Data from 49 older adults (ages 54–92) at two time-points separated by approximately 2.7 years were collected. DTI metrics, including fractional anisotropy (FA) and mean diffusivity (MD), were extracted from nine white matter tracts and global white matter. Results showed that across timepoints, FA and MD increased globally, with no tract-specific changes observed. Baseline age had a global influence on both measures, with increasing age associated with lower FA and higher MD. After controlling for global white matter FA, age additionally predicted FA for the genu, callosum body, inferior fronto-occipital fasciculus (IFOF), and both anterior and posterior cingulum. Females exhibited lower global FA on average compared to males. In contrast, MD was selectively elevated in the anterior cingulum and superior longitudinal fasciculus (SLF), for females compared to males. APOE ε4 status was not predictive of either measure. In summary, these results indicate that age and sex are associated with both global and tract-specific alterations to DTI metrics among a healthy older adult cohort. Older women have poorer white matter integrity compared to older men, perhaps related to menopause-induced metabolic changes. While age-related alterations to white matter integrity are global, there is substantial variation in the degree to which tracts are impacted, possibly as a consequence of tract anatomical variability. The present study highlights the importance of accounting for global sources of variation in DTI metrics when attempting to investigate individual differences (due to age, sex, or other factors) in specific white matter tracts.


2021 ◽  
pp. 1-7
Author(s):  
Szymon Zdanowski ◽  
Alieke Tieks ◽  
Bertus F. Jeronimus ◽  
Marij Zuidersma

Using group-aggregated results and snapshot assessments of cognitive performance may prove problematic if the assessed construct shows substantial and rapid variation over time. To illustrate the significance of this issue, we analyzed cognitive performance data of ten older adults undergoing daily computerized cognitive assessments (CogState Brief Battery) for 36–93 days. In all cases, the day-to-day intra-individual variability was substantial when compared with group-level, between-person variability. This indicates that the results of studies using single snapshot assessments of cognitive functioning should be interpreted with caution. Additionally, group-aggregated measures of cognitive performance may not directly extrapolate to an individual.


2020 ◽  
Author(s):  
T. Hinault ◽  
M. Mijalkov ◽  
J.B. Pereira ◽  
Giovanni. Volpe ◽  
A. Bakker ◽  
...  

AbstractCognitive trajectories vary greatly across older individuals, and the neural mechanisms underlying these differences remain poorly understood. Here, we propose a mechanistic framework of cognitive variability in older adults, linking the influence of white matter microstructure on fast and effective communications between brain regions. Using diffusion tensor imaging and electroencephalography, we show that individual differences in white matter network organization are associated with network clustering and efficiency in the alpha and high-gamma bands, and that functional network dynamics partly explain individual cognitive control performance in older adults. We show that older individuals with high versus low structural network clustering differ in task-related network dynamics and cognitive performance. These findings were corroborated by investigating magnetoencephalography networks in an independent dataset. This multimodal brain connectivity framework of individual differences provides a holistic account of how differences in white matter microstructure underlie age-related variability in dynamic network organization and cognitive performance.


2021 ◽  
Author(s):  
Adeline Jabès ◽  
Giuliana Klencklen ◽  
Paolo Ruggeri ◽  
Christoph M. Michel ◽  
Pamela Banta Lavenex ◽  
...  

AbstractAlterations of resting-state EEG microstates have been associated with various neurological disorders and behavioral states. Interestingly, age-related differences in EEG microstate organization have also been reported, and it has been suggested that resting-state EEG activity may predict cognitive capacities in healthy individuals across the lifespan. In this exploratory study, we performed a microstate analysis of resting-state brain activity and tested allocentric spatial working memory performance in healthy adult individuals: twenty 25–30-year-olds and twenty-five 64–75-year-olds. We found a lower spatial working memory performance in older adults, as well as age-related differences in the five EEG microstate maps A, B, C, C′ and D, but especially in microstate maps C and C′. These two maps have been linked to neuronal activity in the frontal and parietal brain regions which are associated with working memory and attention, cognitive functions that have been shown to be sensitive to aging. Older adults exhibited lower global explained variance and occurrence of maps C and C′. Moreover, although there was a higher probability to transition from any map towards maps C, C′ and D in young and older adults, this probability was lower in older adults. Finally, although age-related differences in resting-state EEG microstates paralleled differences in allocentric spatial working memory performance, we found no evidence that any individual or combination of resting-state EEG microstate parameter(s) could reliably predict individual spatial working memory performance. Whether the temporal dynamics of EEG microstates may be used to assess healthy cognitive aging from resting-state brain activity requires further investigation.


GeroScience ◽  
2021 ◽  
Author(s):  
Monica Baciu ◽  
Sonja Banjac ◽  
Elise Roger ◽  
Célise Haldin ◽  
Marcela Perrone-Bertolotti ◽  
...  

AbstractIn the absence of any neuropsychiatric condition, older adults may show declining performance in several cognitive processes and among them, in retrieving and producing words, reflected in slower responses and even reduced accuracy compared to younger adults. To overcome this difficulty, healthy older adults implement compensatory strategies, which are the focus of this paper. We provide a review of mainstream findings on deficient mechanisms and possible neurocognitive strategies used by older adults to overcome the deleterious effects of age on lexical production. Moreover, we present findings on genetic and lifestyle factors that might either be protective or risk factors of cognitive impairment in advanced age. We propose that “aging-modulating factors” (AMF) can be modified, offering prevention opportunities against aging effects. Based on our review and this proposition, we introduce an integrative neurocognitive model of mechanisms and compensatory strategies for lexical production in older adults (entitled Lexical Access and Retrieval in Aging, LARA). The main hypothesis defended in LARA is that cognitive aging evolves heterogeneously and involves complementary domain-general and domain-specific mechanisms, with substantial inter-individual variability, reflected at behavioral, cognitive, and brain levels. Furthermore, we argue that the ability to compensate for the effect of cognitive aging depends on the amount of reserve specific to each individual which is, in turn, modulated by the AMF. Our conclusion is that a variety of mechanisms and compensatory strategies coexist in the same individual to oppose the effect of age. The role of reserve is pivotal for a successful coping with age-related changes and future research should continue to explore the modulating role of AMF.


2013 ◽  
Vol 26 (4) ◽  
pp. 648-660 ◽  
Author(s):  
Gershon Spitz ◽  
Jerome J. Maller ◽  
Richard O’Sullivan ◽  
Jennie L. Ponsford

2020 ◽  
Vol 79 (OCE2) ◽  
Author(s):  
Sussanne Reyes ◽  
Patricio Peirano ◽  
Betsy Lozoff ◽  
Cecilia Algarin

Abstract IntroductionObesity has been associated with lower white matter integrity (WMI) in limbic brain regions, including the fornix. Both early decrease of WMI in the fornix (WMIf) and midlife obesity have been related to dementia incidence with advancing age. No studies have explored early cognitive predictors of WMIf in overweight-obese (OO) adults. Aim of this study was to compare OO and normal-weight (NW) participants with respect to (a) WMIf in adulthood and (b) the relationship between cognitive performance at school-age and in adolescence with WMIf in adulthood.MethodsParticipants were part of a cohort followed since infancy who underwent magnetic resonance imaging studies in adulthood (22.3 ± 1.3 years). Diffusion tensor imaging was performed and Tract Based Spatial Statistics (TBSS) was used to obtain fractional anisotropy (FA) skeleton; increased FA relates to greater WMI. A mask for the fornix was created (JHU-ICBM DTI-81 Atlas) and then used to extract the average FA for each individual. Participants also performed neurocognitive tasks: (a) school-age (10.3 ± 1.0 years): the trail making test comprises two conditions and time difference between conditions reflects cognitive flexibility; (b) adolescence (15.6 ± 0.5 years): incentive task that test the effect of incentives (reward, loss avoidance or neutral) on inhibitory control performance (correct responses latency). In adulthood, BMI was categorized as NW (≥ 18.5 to < 25.0 kg/m2) and OO (≥ 25.0 kg/m2) groups. A t-test and univariate GLM were conducted. Analysis were adjusted by sex and age-specific BMI z-scores.ResultsParticipants were 27 NW (41% female) and 41 OO (49% female). Compared to NW, OO participants showed decreased FA in the fornix (0.585 vs. 0.618, p < 0.05), i.e. lower WMIf. Differences were apparent in the relationship between cognitive flexibility at school-age (F = 2.9, p = 0.06) and loss avoidance latency in adolescence (F = 3.5, p < 0.05) with FA in the fornix in adulthood. Increased cognitive flexibility at school-age (β = 0.335, p < 0.05) and decreased loss avoidance latency in adolescence (β = -0.581, p < 0.001) were related to higher FA in the fornix in OO adults. No relationship resulted significant in NW adults.DiscussionPerformance in neurocognitive tasks at earlier developmental stages were related with WMIf only in OO adults, group characterized by decreased WMIf. Our results provide evidence regarding specific neurocognitive tasks with predictive value for WMIf alterations. Further, they could contribute to the understanding of neural mechanisms underlying obesity and also provide insight relative to neurodegenerative risk with advancing age.SupportFondecyt 11160671 and NIH HD33487.


2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Claudia Niemann ◽  
Ben Godde ◽  
Claudia Voelcker-Rehage

Physical activity is positively related to cognitive functioning and brain volume in older adults. Interestingly, different types of physical activity vary in their effects on cognition and on the brain. For example, dancing has become an interesting topic in aging research, as it is a popular leisure activity among older adults, involving cardiovascular and motor fitness dimensions that can be positively related to cognition. However, studies on brain structure are missing. In this study, we tested the association of long-term senior dance experience with cognitive performance and gray matter brain volume in older women aged 65 to 82 years. We compared nonprofessional senior dancers (n=28) with nonsedentary control group participants without any dancing experience (n=29), who were similar in age, education, IQ score, lifestyle and health factors, and fitness level. Differences neither in the four tested cognitive domains (executive control, perceptual speed, episodic memory, and long-term memory) nor in brain volume (VBM whole-brain analysis, region-of-interest analysis of the hippocampus) were observed. Results indicate that moderate dancing activity (1-2 times per week, on average) has no additional effects on gray matter volume and cognitive functioning when a certain lifestyle or physical activity and fitness level are reached.


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