The Disconnected Brain and Executive Function Decline in Aging

Fjell, Anders M.; Sneve, Markus Handal; Grydeland, Håkon; Storsve, Andreas Berg; Walhovd, Kristine B.

doi:10.1093/cercor/bhw082

Cited by 160 publications

(161 citation statements)

References 87 publications

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“…However, the energy probabilities of the visual network declined, while the energy probabilities of the default, frontoparietal, and limbic networks decreased further. This result may be consistent with the further enhanced heterogeneity of whole-brain functional subsystems [60][61][62][63][64][65]. The values of EP in the brain regions of the frontoparietal network increased slightly.…”

Section: The Orderness Variability Of Functional Subsystems With Agesupporting

confidence: 83%

Lifespan Development of the Human Brain Revealed by Large-Scale Network Eigen-Entropy

Fan

Zeng

Shen

et al. 2017

Entropy

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Abstract:Imaging connectomics based on graph theory has become an effective and unique methodological framework for studying functional connectivity patterns of the developing and aging brain. Normal brain development is characterized by continuous and significant network evolution through infancy, childhood, and adolescence, following specific maturational patterns. Normal aging is related to some resting state brain networks disruption, which are associated with certain cognitive decline. It is a big challenge to design an integral metric to track connectome evolution patterns across the lifespan, which is to understand the principles of network organization in the human brain. In this study, we first defined a brain network eigen-entropy (NEE) based on the energy probability (EP) of each brain node. Next, we used the NEE to characterize the lifespan orderness trajectory of the whole-brain functional connectivity of 173 healthy individuals ranging in age from 7 to 85 years. The results revealed that during the lifespan, the whole-brain NEE exhibited a significant non-linear decrease and that the EP distribution shifted from concentration to wide dispersion, implying orderness enhancement of functional connectome over age. Furthermore, brain regions with significant EP changes from the flourishing (7-20 years) to the youth period (23-38 years) were mainly located in the right prefrontal cortex and basal ganglia, and were involved in emotion regulation and executive function in coordination with the action of the sensory system, implying that self-awareness and voluntary control performance significantly changed during neurodevelopment. However, the changes from the youth period to middle age (40-59 years) were located in the mesial temporal lobe and caudate, which are associated with long-term memory, implying that the memory of the human brain begins to decline with age during this period. Overall, the findings suggested that the human connectome shifted from a relatively anatomical driven state to an orderly organized state with lower entropy.

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Section: The Orderness Variability Of Functional Subsystems With Agesupporting

confidence: 83%

Lifespan Development of the Human Brain Revealed by Large-Scale Network Eigen-Entropy

Fan

Zeng

Shen

et al. 2017

Entropy

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“…To assess the comparability of the results with data from the now more commonly used 3T scanners and longer scanning sequences, 44 young participants were scanned both on the 1.5T scanner with 100 volumes, and on a 3T scanner with 150 volumes on the same day. Previously reported validation analyses (Fjell et al, 2016a) demonstrated excellent convergence between network structure detected across 1.5 and 3T scanners and 100 vs. 150 volumes…”

Section: Methodsmentioning

confidence: 77%

Relationship between structural and functional connectivity change across the adult lifespan: A longitudinal investigation

Fjell

Sneve

Grydeland

et al. 2016

Human Brain Mapping

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Extensive efforts are devoted to understand the functional (FC) and structural connections (SC) of the brain. FC is usually measured by functional magnetic resonance imaging (fMRI), and conceptualized as degree of synchronicity in brain activity between different regions. SC is typically indexed by measures of white matter (WM) properties, e.g. by diffusion weighted imaging (DWI). FC and SC are intrinsically related, in that coordination of activity across regions ultimately depends on fast and efficient transfer of information made possible by structural connections. Convergence between FC and SC has been shown for specific networks, especially the default mode network (DMN). However, it is not known to what degree FC is constrained by major WM tracts and whether FC and SC change together over time. Here, 120 participants (20-85 years) were tested at two time points, separated by 3.3 years. Resting-state fMRI was used to measure FC, and DWI to measure WM microstructure as an index of SC. TRACULA, part of FreeSurfer, was used for automated tractography of 18 major WM tracts. Cortical regions with tight structural couplings defined by tractography were only weakly related at the functional level. Certain regions of the DMN showed a modest relationship between change in FC and SC, but for the most part, the two measures changed independently. The main conclusions are that anatomical alignment of SC and FC seems restricted to specific networks and tracts, and that changes in SC and FC are not necessarily strongly correlated.

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“…Normal age-related structural and functional connectivity alterations independent of decision making are not the focus of the present study and have already been reported and reviewed in the literature elsewhere (Andrews-Hanna et al, 2007; Ferreira and Busatto, 2013; Antonenko and Flöel, 2014; Bennett and Madden, 2014; Dennis and Thompson, 2014; Sexton et al, 2014; Sala-Llonch et al, 2015; Ferreira et al, 2016; Fjell et al, 2016). In summary, these studies showed that there is a normal age-related decline in structural as well as functional connectivity strength that is not uniformly distributed throughout the brain, i.e., the magnitude of connectivity reductions differs between brain regions.…”

Section: Introductionmentioning

confidence: 78%

Strength of Structural and Functional Frontostriatal Connectivity Predicts Self-Control in the Healthy Elderly

Hänggi

Lohrey

Drobetz

et al. 2016

Front. Aging Neurosci.

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Self-regulation refers to the successful use of executive functions and initiation of top-down processes to control one's thoughts, behavior, and emotions, and it is crucial to perform self-control. Self-control is needed to overcome impulses and can be assessed by delay of gratification (DoG) and delay discounting (DD) paradigms. In children/adolescents, good DoG/DD ability depends on the maturity of frontostriatal connectivity, and its decline in strength with advancing age might adversely affect self-control because prefrontal brain regions are more prone to normal age-related atrophy than other regions. Here, we aimed at highlighting the relationship between frontostriatal connectivity strength and DoG performance in advanced age. We recruited 40 healthy elderly individuals (mean age 74.0 ± 7.7 years) and assessed the DoG ability using the German version of the DoG test for adults in addition to the delay discounting (DD) paradigm. Based on diffusion-weighted and resting-state functional magnetic resonance imaging data, respectively, the structural and functional whole-brain connectome were reconstructed based on 90 different brain regions of interest in addition to a 12-node frontostriatal DoG-specific network and the resulting connectivity matrices were subjected to network-based statistics. The 90-nodes whole-brain connectome analyses revealed subnetworks significantly associated with DoG and DD with a preponderance of frontostriatal nodes involved suggesting a high specificity of the findings. Structural and functional connectivity strengths between the putamen, caudate nucleus, and nucleus accumbens on the one hand and orbitofrontal, dorsal, and ventral lateral prefrontal cortices on the other hand showed strong positive correlations with DoG and negative correlations with DD corrected for age, sex, intracranial volume, and head motion parameters. These associations cannot be explained by differences in impulsivity and executive functioning. This pattern of correlations between structural or functional frontostriatal connectivity strength and self-control suggests that, in addition to the importance of the frontostriatal nodes itself, the structural and functional properties of different connections within the frontostriatal network are crucial for self-controlled behaviors in the healthy elderly. Because high DoG/low DD is a significant predictor of willpower and wellbeing in the elderly population, interventions aiming at strengthening frontostriatal connectivity to strengthen self-controlled behavior are needed in the future.

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The Disconnected Brain and Executive Function Decline in Aging

Cited by 160 publications

References 87 publications

Lifespan Development of the Human Brain Revealed by Large-Scale Network Eigen-Entropy

Lifespan Development of the Human Brain Revealed by Large-Scale Network Eigen-Entropy

Relationship between structural and functional connectivity change across the adult lifespan: A longitudinal investigation

Strength of Structural and Functional Frontostriatal Connectivity Predicts Self-Control in the Healthy Elderly

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