Changes in white-matter functional network efficiency across the adult lifespan

Neuroreport ◽  
2019 ◽  
Vol 30 (8) ◽  
pp. 600-604 ◽  
Author(s):  
Heng Niu ◽  
Jiajia Zhu ◽  
Chunli Wang ◽  
Lina Zhu ◽  
Jiang Wu
Keyword(s):  
White Matter ◽  
Functional Network ◽  
Network Efficiency ◽  
Adult Lifespan

scholarly journals The superficial white matter in temporal lobe epilepsy: a key link between structural and functional network disruptions

Brain ◽  
2016 ◽  
Vol 139 (9) ◽  
pp. 2431-2440 ◽  
Author(s):  
Min Liu ◽  
Boris C. Bernhardt ◽  
Seok-Jun Hong ◽  
Benoit Caldairou ◽  
Andrea Bernasconi ◽  
...  
Keyword(s):  
White Matter ◽  
Temporal Lobe Epilepsy ◽  
Temporal Lobe ◽  
Functional Network ◽  
Network Disruptions

scholarly journals Organization of cortico-cortical pathways supporting memory retrieval across subregions of the left ventrolateral prefrontal cortex

2016 ◽  
Vol 116 (3) ◽  
pp. 920-937 ◽  
Author(s):  
Jennifer Barredo ◽  
Timothy D. Verstynen ◽  
David Badre
Keyword(s):  
Prefrontal Cortex ◽  
White Matter ◽  
Functional Connectivity ◽  
Memory Retrieval ◽  
Temporal Cortex ◽  
Functional Network ◽  
High Angular Resolution ◽  
Connectivity Analysis ◽  
Ventrolateral Prefrontal Cortex ◽  
Functional Connectivity Analysis

Functional magnetic resonance imaging (fMRI) evidence indicates that different subregions of ventrolateral prefrontal cortex (VLPFC) participate in distinct cortical networks. These networks have been shown to support separable cognitive functions: anterior VLPFC [inferior frontal gyrus (IFG) pars orbitalis] functionally correlates with a ventral fronto-temporal network associated with top-down influences on memory retrieval, while mid-VLPFC (IFG pars triangularis) functionally correlates with a dorsal fronto-parietal network associated with postretrieval control processes. However, it is not known to what extent subregional differences in network affiliation and function are driven by differences in the organization of underlying white matter pathways. We used high-angular-resolution diffusion spectrum imaging and functional connectivity analysis in unanesthetized humans to address whether the organization of white matter connectivity differs between subregions of VLPFC. Our results demonstrate a ventral-dorsal division within IFG. Ventral IFG as a whole connects broadly to lateral temporal cortex. Although several different individual white matter tracts form connections between ventral IFG and lateral temporal cortex, functional connectivity analysis of fMRI data indicates that these are part of the same ventral functional network. By contrast, across subdivisions, dorsal IFG was connected with the midfrontal gyrus and correlated as a separate dorsal functional network. These qualitative differences in white matter organization within larger macroanatomical subregions of VLPFC support prior functional distinctions among these regions observed in task-based and functional connectivity fMRI studies. These results are consistent with the proposal that anatomical connectivity is a crucial determinant of systems-level functional organization of frontal cortex and the brain in general.

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 A watershed model of individual differences in fluid intelligence

2016 ◽  
Author(s):  
Rogier A. Kievit ◽  
Simon W. Davis ◽  
John Griffiths ◽  
Marta Correia ◽  
Cam-CAN ◽  
...  
Keyword(s):  
White Matter ◽  
Processing Speed ◽  
Fluid Intelligence ◽  
White Matter Integrity ◽  
Life Outcomes ◽  
Watershed Model ◽  
Adult Lifespan ◽  
Large N ◽  
Competing Models ◽  
The One

AbstractFluid intelligence is a crucial cognitive ability that predicts key life outcomes across the lifespan. Strong empirical links exist between fluid intelligence and processing speed on the one hand, and white matter integrity and processing speed on the other. We propose a watershed model that integrates these three explanatory levels in a principled manner in a single statistical model, with processing speed and white matter figuring as intermediate endophenotypes. We fit this model in a large (N=555) adult lifespan cohort from the Cambridge Centre for Ageing and Neuroscience (Cam-CAN) using multiple measures of processing speed, white matter health and fluid intelligence. The model fit the data well, outperforming competing models and providing evidence for a many-to-one mapping between white matter integrity, processing speed and fluid intelligence. The model can be naturally extended to integrate other cognitive domains, endophenotypes and genotypes.

scholarly journals Nicotine increases brain functional network efficiency

NeuroImage ◽  
2012 ◽  
Vol 63 (1) ◽  
pp. 73-80 ◽  
Author(s):  
Korey P. Wylie ◽  
Donald C. Rojas ◽  
Jody Tanabe ◽  
Laura F. Martin ◽  
Jason R. Tregellas
Keyword(s):  
Functional Network ◽  
Network Efficiency ◽  
Brain Functional Network

scholarly journals White matter microstructural integrity across the adult lifespan: Combined perspective of diffusion tensor and kurtosis imaging

2021 ◽  
Author(s):  
Hiba Taha ◽  
Jordan A Chad ◽  
J. Jean Chen
Keyword(s):  
White Matter ◽  
Brain Aging ◽  
Diffusion Tensor ◽  
Diffusion Imaging ◽  
General Pattern ◽  
B Value ◽  
Diffusion Kurtosis Imaging ◽  
Adult Lifespan ◽  
Non Gaussian ◽  
Diffusion Kurtosis

Studies of healthy brain aging have reported diffusivity patterns associated with white matter degeneration using diffusion tensor imaging (DTI), which assumes that diffusion measured at the typical b-value (approximately 1000 s/mm2) is Gaussian. Diffusion kurtosis imaging (DKI) is an extension of DTI that measures non-Gaussian diffusion (kurtosis) to better capture microenvironmental changes by incorporating additional data at a higher b-value. In this study, using UK Biobank data (b values of 1000 and 2000 s/mm2), we investigate (1) the extent of novel information gained from adding diffusional kurtosis to diffusivity observations in aging, and (2) how conventional DTI metrics in aging compare with diffusivity metrics derived from DKI, which are corrected for kurtosis. We find a general pattern of lower kurtosis alongside higher diffusivity among older adults. We also find differences between diffusivity metrics derived from DTI and DKI, emphasizing the importance of accounting for non-Gaussian diffusion. This work highlights the utility of measuring diffusional kurtosis as a simple addition to conventional diffusion imaging of aging.

Age Affects White Matter Integrity and Episodic Memory Across the Older Adult Lifespan

2020 ◽  
Author(s):  
Jenna Merenstein ◽  
María M. Corrada ◽  
Claudia H. Kawas ◽  
Ilana J. Bennett
Keyword(s):  
Cognitive Impairment ◽  
White Matter ◽  
Episodic Memory ◽  
Older Adult ◽  
Diffusion Tensor ◽  
Oldest Old ◽  
White Matter Integrity ◽  
Adult Lifespan ◽  
Increased Risk ◽  
Effect Of Age

Aging is accompanied by declines in white matter integrity (e.g., demyelination, decreased fiber density) that contribute to cognitive deficits. Diffusion tensor imaging (DTI) studies have observed these integrity declines in vivo separately in younger-old (ages 65-89) and oldest-old (ages 90+) adults. But it remains unclear whether the effect of age on integrity is magnified in advanced age groups and whether this may result from normal aging or dementia-related pathology. Here, we tested whether age-related differences in white matter integrity followed linear or nonlinear patterns when considering the entire older adult lifespan (n = 108; 65-98 years) and whether these patterns were influenced by oldest-old adults at increased risk of dementia (cognitive impairment no dementia, CIND). To assess the functional impact of white matter aging, we then examined the extent to which it explained age effects on episodic memory performance (delayed recall, recognition). Results revealed significant nonlinear declines in the integrity of medial temporal, callosal, and association fiber classes, with linear declines observed for the projection/thalamic fiber class. These patterns remained after excluding the oldest-old participants with CIND, indicating that larger differences in white matter integrity with increased age cannot solely be explained by pathology associated with early cognitive impairment. We also found that the effect of age on episodic memory was partially mediated by integrity of medial temporal fibers, suggesting that they are essential for facilitating memory-related neural signals across the older adult lifespan.

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