scholarly journals Functional Connectivity in Aging

2019 ◽  
Author(s):  
Franziskus Liem ◽  
Linda Geerligs ◽  
Jessica S. Damoiseaux ◽  
Daniel S. Margulies

A large body of research shows that aging is accompanied by localized changes in brain structure and function. However, over the past decade the neuroimaging community has begun to recognize the importance of investigating the brain as a network. Brain regions don’t function independently, rather they form an expansive network that allows for communication between distant areas and enables complex cognitive functioning. Hence, age-related changes in the network structure might explain changes in cognitive functioning.Characterizing this network by investigating the brain’s functional connectivity has enabled new insights into brain organization. In this chapter, we will outline how the brain’s functional connectivity is affected by aging and how changes in functional connectivity relate to changes in cognitive functioning. We will address how neurodegenerative pathology influences functional connectivity and how, based on these measurements, biomarkers for clinical outcome might be developed in the future.

2019 ◽  
Vol 3 (4) ◽  
Author(s):  
Chelsea M. Stillman ◽  
Shannon D. Donofry ◽  
Kirk I. Erickson

Aging is associated with changes in brain structure and function with some brain regions showing more age-related deterioration than others. There is evidence that regional changes in brain structure and function may affect the functioning of other, less- age-sensitive brain regions and lead to more global changes in brain efficiency and cognitive functioning. Fortunately, emerging evidence from health neuroscience suggests that age-related brain changes and associated cognitive declines may not be inevitable. In fact, they may even be reversible. Exercise is a particularly promising health behavior known to induce changes in regional brain structure and function in older adults. However, much less is known about how exercise affects the organization of brain networks in late life. The purpose of this review is to summarize what is known to date regarding the relationships between functional connectivity, exercise, fitness, and physical activity in aging. A critical summary of this literature may reveal novel mechanisms by which physical activity influences brain health, which in turn may be leveraged to improve other aspects of functioning, including physical, cognitive, and mental health in late life.


2019 ◽  
Author(s):  
František Váša ◽  
Rafael Romero-Garcia ◽  
Manfred G. Kitzbichler ◽  
Jakob Seidlitz ◽  
Kirstie J. Whitaker ◽  
...  

AbstractAdolescent changes in human brain function are not entirely understood. Here we used multi-echo functional magnetic resonance imaging (fMRI) to measure developmental change in functional connectivity (FC) of resting-state oscillations between pairs of 330 cortical regions and 16 subcortical regions in N=298 healthy adolescents. Participants were aged 14-26 years and were scanned on two or more occasions at least 6 months apart. We found two distinct modes of age-related change in FC: “conservative” and “disruptive”. Conservative development was characteristic of primary cortex, which was strongly connected at 14 years and became even more connected in the period 14-26 years. Disruptive development was characteristic of association cortex, hippocampus and amygdala, which were not strongly connected at 14 years but became more strongly connected during adolescence. We defined the maturational index (MI) as the signed coefficient of the linear relationship between baseline FC (at 14 years,FC14) and adolescent change in FC (∆FC14−26). Disruptive systems (with negative MI) were functionally specialised for social cognition and autobiographical memory and were significantly co-located with prior maps of aerobic glycolysis (AG), AG-related gene expression, post-natal expansion of cortical surface area, and adolescent shrinkage of cortical depth. We conclude that human brain organization is disrupted during adolescence by the emergence of strong functional connectivity of subcortical nuclei and association cortical areas, representing metabolically expensive re-modelling of synaptic connectivity between brain regions that were not strongly connected in childhood. We suggest that this re-modelling process may support emergence of social skills and self-awareness during healthy human adolescence.


2019 ◽  
Vol 116 (42) ◽  
pp. 21219-21227 ◽  
Author(s):  
Bertha Vázquez-Rodríguez ◽  
Laura E. Suárez ◽  
Ross D. Markello ◽  
Golia Shafiei ◽  
Casey Paquola ◽  
...  

The white matter architecture of the brain imparts a distinct signature on neuronal coactivation patterns. Interregional projections promote synchrony among distant neuronal populations, giving rise to richly patterned functional networks. A variety of statistical, communication, and biophysical models have been proposed to study the relationship between brain structure and function, but the link is not yet known. In the present report we seek to relate the structural and functional connection profiles of individual brain areas. We apply a simple multilinear model that incorporates information about spatial proximity, routing, and diffusion between brain regions to predict their functional connectivity. We find that structure–function relationships vary markedly across the neocortex. Structure and function correspond closely in unimodal, primary sensory, and motor regions, but diverge in transmodal cortex, particularly the default mode and salience networks. The divergence between structure and function systematically follows functional and cytoarchitectonic hierarchies. Altogether, the present results demonstrate that structural and functional networks do not align uniformly across the brain, but gradually uncouple in higher-order polysensory areas.


2021 ◽  
Vol 23 (1) ◽  
pp. 305
Author(s):  
Eunsoo Won ◽  
Kyoung-Sae Na ◽  
Yong-Ku Kim

Pro-inflammatory systemic conditions that can cause neuroinflammation and subsequent alterations in brain regions involved in emotional regulation have been suggested as an underlying mechanism for the pathophysiology of major depressive disorder (MDD). A prominent feature of MDD is disruption of circadian rhythms, of which melatonin is considered a key moderator, and alterations in the melatonin system have been implicated in MDD. Melatonin is involved in immune system regulation and has been shown to possess anti-inflammatory properties in inflammatory conditions, through both immunological and non-immunological actions. Melatonin has been suggested as a highly cytoprotective and neuroprotective substance and shown to stimulate all stages of neuroplasticity in animal models. The ability of melatonin to suppress inflammatory responses through immunological and non-immunological actions, thus influencing neuroinflammation and neurotoxicity, along with subsequent alterations in brain regions that are implicated in depression, can be demonstrated by the antidepressant-like effects of melatonin. Further studies that investigate the associations between melatonin, immune markers, and alterations in the brain structure and function in patients with depression could identify potential MDD biomarkers.


2022 ◽  
Vol 5 (1) ◽  
Author(s):  
Hyebin Lee ◽  
Junmo Kwon ◽  
Jong-eun Lee ◽  
Bo-yong Park ◽  
Hyunjin Park

AbstractFunctional hierarchy establishes core axes of the brain, and overweight individuals show alterations in the networks anchored on these axes, particularly in those involved in sensory and cognitive control systems. However, quantitative assessments of hierarchical brain organization in overweight individuals are lacking. Capitalizing stepwise functional connectivity analysis, we assess altered functional connectivity in overweight individuals relative to healthy weight controls along the brain hierarchy. Seeding from the brain regions associated with obesity phenotypes, we conduct stepwise connectivity analysis at different step distances and compare functional degrees between the groups. We find strong functional connectivity in the somatomotor and prefrontal cortices in both groups, and both converge to transmodal systems, including frontoparietal and default-mode networks, as the number of steps increased. Conversely, compared with the healthy weight group, overweight individuals show a marked decrease in functional degree in somatosensory and attention networks across the steps, whereas visual and limbic networks show an increasing trend. Associating functional degree with eating behaviors, we observe negative associations between functional degrees in sensory networks and hunger and disinhibition-related behaviors. Our findings suggest that overweight individuals show disrupted functional network organization along the hierarchical axis of the brain and these results provide insights for behavioral associations.


2017 ◽  
Vol 23 (9-10) ◽  
pp. 843-859 ◽  
Author(s):  
Edith V. Sullivan

AbstractAlcohol use disorder (AUD) has been a major cause of family, social, and personal strife for centuries, with current prevalence estimates of 14% for 12-month and 29% lifetime AUD. Neuropsychological testing of selective cognitive, sensory, and motor functions complemented within vivobrain imaging has enabled tracking the consequences of AUD, which follows a dynamic course of development, maintenance, and recovery or relapse. Controlled studies of alcoholism reviewed herein provide evidence for disruption of selective functions involving executive, visuospatial, mnemonic, emotional, and attentional processes, response inhibition, prosody, and postural stability and brain systems supporting these functions. On a hopeful front, longitudinal study provides convincing evidence for improvement in brain structure and function following sustained sobriety. These discoveries have a strong legacy in the International Neuropsychological Society (INS), starting from its early days when assumptions regarding which brain regions were disrupted relied solely on patterns of functional sparing and impairment deduced from testing. This review is based on the symposium presentation delivered at the 2017 annual North American meeting of the INS in celebration of the 50th anniversary since its institution in 1967. In the spirit of the meeting’s theme, “Binding the Past and Present,” the lecture and this review recognized the past by focusing on early, rigorous neuropsychological studies of alcoholism and their influence on research currently conducted using imaging methods enabling hypothesis testing of brain substrates of observed functional deficits. (JINS, 2017,23, 843–859)


1997 ◽  
Vol 352 (1362) ◽  
pp. 1703-1709 ◽  
Author(s):  
◽  
Marilyn S. Albert

With advancing age, the majority of individuals experience declines in their ability to learn and remember. An examination of brain structure and function in healthy older persons across the age range indicates that there are substantial changes in the brain that appear to be related to alterations in memory. The nature of the cognitive and neurobiological alterations associated with age-related change is substantially different from that seen in the early stages of a dementing illness, such as Alzheimer's disease. These differences have implications for potential intervention strategies.


2021 ◽  
Author(s):  
Gidon Levakov ◽  
Joshua Faskowitz ◽  
Galia Avidan ◽  
Olaf Sporns

AbstractThe connectome, a comprehensive map of the brain’s anatomical connections, is often summarized as a matrix comprising all dyadic connections among pairs of brain regions. This representation cannot capture higher-order relations within the brain graph. Connectome embedding (CE) addresses this limitation by creating compact vectorized representations of brain nodes capturing their context in the global network topology. Here, nodes “context” is defined as random walks on the brain graph and as such, represents a generative model of diffusive communication around nodes. Applied to group-averaged structural connectivity, CE was previously shown to capture relations between inter-hemispheric homologous brain regions and uncover putative missing edges from the network reconstruction. Here we extend this framework to explore individual differences with a novel embedding alignment approach. We test this approach in two lifespan datasets (NKI: n=542; Cam-CAN: n=601) that include diffusion-weighted imaging, resting-state fMRI, demographics and behavioral measures. We demonstrate that modeling functional connectivity with CE substantially improves structural to functional connectivity mapping both at the group and subject level. Furthermore, age-related differences in this structure-function mapping are preserved and enhanced. Importantly, CE captures individual differences by out-of-sample prediction of age and intelligence. The resulting predictive accuracy was higher compared to using structural connectivity and functional connectivity. We attribute these findings to the capacity of the CE to incorporate aspects of both anatomy (the structural graph) and function (diffusive communication). Our novel approach allows mapping individual differences in the connectome through structure to function and behavior.


Author(s):  
Maxwell H Turner ◽  
Kevin Mann ◽  
Thomas R. Clandinin

Connectomic datasets have emerged as invaluable tools for understanding neural circuits in many systems. What constraints does the connectome place on information processing and routing in a large scale neural circuit? For mesoscale brain networks, the relationship between cell and synaptic level connectivity and brain function is not well understood. Here, we use data from the Drosophila connectome in conjunction with whole-brain in vivo imaging to relate structural and functional connectivity in the central brain. We find that functional connectivity is strongly associated with the strength of both direct and indirect anatomical pathways. We also show that some brain regions, including the mushroom body and central complex, show considerably higher functional connectivity to other brain regions than is predicted based on their direct anatomical connections. We find several key topological similarities between mesoscale brain networks in flies and mammals, revealing conserved principles relating brain structure and function.


2019 ◽  
Vol 13 ◽  
pp. 117906951985180 ◽  
Author(s):  
Tonya White ◽  
Vince D. Calhoun

The ability to measure the intrinsic functional architecture of the brain has grown exponentially over the last 2 decades. Measures of intrinsic connectivity within the brain, typically measured using resting-state functional magnetic resonance imaging (MRI), have evolved from primarily “static” approaches, to include dynamic measures of functional connectivity. Measures of dynamic functional connectivity expand the assumptions to allow brain regions to have temporally different patterns of communication between different regions. That is, connections within the brain can differentially fire between different regions at different times, and these differences can be quantified. Applying approaches that measure the dynamic characteristics of functional brain connectivity have been fruitful in identifying differences during brain development and psychopathology. We provide a brief overview of static and dynamic measures of functional connectivity and illustrate the synergy in applying these approaches to identify both age-related differences in children and differences between typically developing children and children with autistic symptoms.


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