Disrupted Neural Synchrony Mediates the Relationship between White Matter Integrity and Cognitive Performance in Older Adults

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.

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Changes in Cerebral Volume and White Matter Integrity in Adults on Hemodialysis and Relationship to Cognitive Function

Nephron ◽

10.1159/000510614 ◽

2020 ◽

Vol 145 (1) ◽

pp. 35-43

Author(s):

Wesley T. Richerson ◽

Laura G. Umfleet ◽

Brian D. Schmit ◽

Dawn F. Wolfgram

Keyword(s):

Cognitive Impairment ◽

White Matter ◽

Cognitive Performance ◽

Gray Matter ◽

Structural Changes ◽

Structural Integrity ◽

Diffusion Tensor ◽

White Matter Integrity ◽

Healthy Controls ◽

Matter Volume

Introduction: Patients on hemodialysis (HD) have a significant burden of cognitive impairment. Characterizing the cerebral structural changes in HD patients compared to healthy controls and evaluating the relationship of cerebral structural integrity with cognitive performance in HD patients can help clarify the pathophysiology of the cognitive impairment in HD patients. Methods: In this cross-sectional study, in-center HD patients ≥50 years of age underwent brain structural and diffusion MRIs and cognitive assessment using the NIH Toolbox cognition battery. The cerebral imaging measures of the HD participants were compared to imaging from age-matched controls. Gray matter volume, white matter volume, and white matter integrity determined by diffusion tensor imaging parameters (including fractional anisotropy [FA]) were measured in both cohorts to determine differences in the cerebral structure between HD participants and healthy controls. The association between cognitive performance on the NIH Toolbox cognition battery and cerebral structural integrity was evaluated using multiple linear regression models. Results: We compared imaging measures form 23 HD participants and 15 age-matched controls. The HD participants had decreased gray matter volumes (526.8 vs. 589.5 cm3, p < 0.01) and worsened white matter integrity overall (FA values of 0.2864 vs. 0.3441, p < 0.01) within major white matter tracts compared to healthy controls. Decreases in white matter integrity in the left superior longitudinal fasciculus was associated with lower executive function scores (r2 = 0.24, p = 0.02) and inferior longitudinal fasciculus with lower memory scores (r = 0.25 and p = 0.03 for left and r2 = 0.21 and p = 0.03 for right). Conclusions: HD patients have a pattern of decreased white matter integrity and gray matter atrophy compared to controls. Decreases in white matter integrity were associated with decreased cognitive performance in the HD population.

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Age-related differences in network structure and dynamic synchrony of cognitive control

10.1101/2020.10.09.333567 ◽

2020 ◽

Author(s):

T. Hinault ◽

M. Mijalkov ◽

J.B. Pereira ◽

Giovanni. Volpe ◽

A. Bakker ◽

...

Keyword(s):

Older Adults ◽

Individual Differences ◽

White Matter ◽

Cognitive Control ◽

Cognitive Performance ◽

Network Dynamics ◽

Network Clustering ◽

Older Individuals ◽

Age Related ◽

White Matter Microstructure

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.

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The Association between High Neuroticism-Low Extraversion and Dual-Task Performance during Walking While Talking in Non-demented Older Adults

Journal of the International Neuropsychological Society ◽

10.1017/s1355617715000570 ◽

2015 ◽

Vol 21 (7) ◽

pp. 519-530 ◽

Cited By ~ 7

Author(s):

Brittany C. LeMonda ◽

Jeannette R. Mahoney ◽

Joe Verghese ◽

Roee Holtzer

Keyword(s):

Older Adults ◽

Task Performance ◽

Cognitive Performance ◽

Dual Task ◽

Stress Test ◽

Adverse Outcomes ◽

Task Demands ◽

Gait Velocity ◽

Older Individuals ◽

Dual Task Performance

AbstractThe Walking While Talking (WWT) dual-task paradigm is a mobility stress test that predicts major outcomes, including falls, frailty, disability, and mortality in aging. Certain personality traits, such as neuroticism, extraversion, and their combination, have been linked to both cognitive and motor outcomes. We examined whether individual differences in personality dimensions of neuroticism and extraversion predicted dual-task performance decrements (both motor and cognitive) on a WWT task in non-demented older adults. We hypothesized that the combined effect of high neuroticism-low extraversion would be related to greater dual-task costs in gait velocity and cognitive performance in non-demented older adults. Participants (N=295; age range,=65–95 years; female=164) completed the Big Five Inventory and WWT task involving concurrent gait and a serial 7’s subtraction task. Gait velocity was obtained using an instrumented walkway. The high neuroticism-low extraversion group incurred greater dual-task costs (i.e., worse performance) in both gait velocity {95% confidence interval (CI) [−17.68 to −3.07]} and cognitive performance (95% CI [−19.34 to −2.44]) compared to the low neuroticism-high extraversion group, suggesting that high neuroticism-low extraversion interferes with the allocation of attentional resources to competing task demands during the WWT task. Older individuals with high neuroticism-low extraversion may be at higher risk for falls, mobility decline and other adverse outcomes in aging. (JINS, 2015, 21, 519–530)

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Locus coeruleus integrity in old age is selectively related to memories linked with salient negative events

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1712268115 ◽

2018 ◽

Vol 115 (9) ◽

pp. 2228-2233 ◽

Cited By ~ 41

Author(s):

Dorothea Hämmerer ◽

Martina F. Callaghan ◽

Alexandra Hopkins ◽

Julian Kosciessa ◽

Matthew Betts ◽

...

Keyword(s):

Older Adults ◽

Locus Coeruleus ◽

Structural Integrity ◽

Memory Task ◽

Negative Events ◽

Older Individuals ◽

Healthy Older Adults ◽

Aversive Events ◽

Strong Motivation ◽

Noradrenergic Modulation

The locus coeruleus (LC) is the principal origin of noradrenaline in the brain. LC integrity varies considerably across healthy older individuals, and is suggested to contribute to altered cognitive functions in aging. Here we test this hypothesis using an incidental memory task that is known to be susceptible to noradrenergic modulation. We used MRI neuromelanin (NM) imaging to assess LC structural integrity and pupillometry as a putative index of LC activation in both younger and older adults. We show that older adults with reduced structural LC integrity show poorer subsequent memory. This effect is more pronounced for emotionally negative events, in accord with a greater role for noradrenergic modulation in encoding salient or aversive events. In addition, we found that salient stimuli led to greater pupil diameters, consistent with increased LC activation during the encoding of such events. Our study presents novel evidence that a decrement in noradrenergic modulation impacts on specific components of cognition in healthy older adults. The findings provide a strong motivation for further investigation of the effects of altered LC integrity in pathological aging.

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