Age-related Structural and Functional Variations in 5967 Individuals across the Adult Lifespan

Abstract

Exploring brain changes across the human lifespan is becoming an important topic in neuroscience. Though there are multiple studies which investigated the relationship between age and brain imaging data, the results are heterogeneous due to small sample sizes and relatively narrow age ranges. Here, based on year-wise estimation of 5967 subjects from 13 to 72 years old, we aimed to provide a more precise description of adult lifespan variation trajectories of gray matter volume (GMV), structural network correlation (SNC) and functional network connectivity (FNC) using independent component analysis and multivariate linear regression model. Our results revealed the following relationships: 1)GMV linearly declined with age in most regions, while parahippocampus showed an inverted U-shape quadratic relationship with age; SNC presented a U-shape quadratic relationship with age within cerebellum, and inverted U-shape relationship primarily in the default mode network (DMN) and frontoparietal (FP) related correlation. 2) FNC tended to linearly decrease within resting-state networks (RSNs), especially in visual network and DMN. Early increase was revealed between RSNs, primarily in FP and DMN, which experienced decrease at older ages. U-shape relationship was also revealed to compensate for the cognition deficit in attention and subcortical related connectivity at late years. 3) The link between middle occipital gyrus and insula, as well as precuneus and cerebellum, exhibited similar changing trends between SNC and FNC across the adult lifespan. Collectively, these results highlight the benefit of lifespan study and provide a precise description of age-related regional variation and SNC/FNC changes based on a large dataset.

Functional Brain Network Connectivity Patterns Associated With Normal Cognition at Old-Age, Local β-amyloid, Tau, and APOE4

“…This particularly affects brain regions such as the thalamus, putamen, superior cerebellar gray, choroid plexus, but also meninges and skull, posing challenges when studying early tau accumulation, as done in the current study (Baker et al, 2019). Functional coupling between the PCP and the PCC is well known, and our finding of an association with local β-amyloid may accord with earlier reports on altered functional brain changes during aging (Steininger et al, 2014;Liu et al, 2017;Luo et al, 2019). However, considering that no significant cerebellar β-amyloid accumulation is to be expected in cognitively healthy individuals (Thal et al, 2002), also this finding needs further replication, and for now, needs to be interpreted with caution.…”

The older adult brain is less modular, more integrated, and less efficient at rest: A systematic review of large‐scale resting‐state functional brain networks in aging

“…In large sample of 5967 subjects aged 13 to 72 years, Luo et al (2020) found varied patterns of network correlations with age. Within-network connectivity decreased linearly, particularly in the visual and default mode networks.…”

“…Seventeen studies reported on the default mode network separately, with 15 (88%) reporting increased connectivity to other large-scale networks. In contrast, 12 studies reported networks with decreased connectivity to primary sensory, motor and attention networks, such as between the motor regions and other restingstate networks (Allen et al, 2011;Geerligs et al, 2015;Hou et al, 2019;Luo et al, 2020;Wang et al, 2012;Zhai & Li, 2019), between the salience network and the visual, auditory and sensorimotor networks (Hou et al, 2019;Monteiro et al, 2019;Onoda et al, 2012;Vij et al, 2018), and between sub-regions of the default mode, visual, auditory and dorsal attention networks (Huang et al, 2015;Spreng et al, 2016;Viviano et al, 2017;Zhai & Li, 2019;Zonneveld et al, 2019). Lower connectivity between the supplementary motor area and left anterior insular cortex has also been reported with increasing age (Li et al, 2015).…”

“…3.3.1 | Higher-order and lower-order networks show different age trajectories of between-network connectivity Decreases in between-network connectivity of associative networks was relatively uncommon, reported in two of the 37 (5%) studies reviewed (Luo et al, 2020;. Seventeen studies reported on the default mode network separately, with 15 (88%) reporting increased connectivity to other large-scale networks.…”

“…There is evidence that the trajectory of age-related differences in resting-state functional network connectivity are non-linear, typically showing a quadratic pattern with age. Investigation of these non-linear relationships was reported in eight studies (see Table S1) at varying spatial scales, showing an inflection point in the third decade for within-network connectivity, and in the fourth decade for between-network connectivity (Betzel et al, 2014;Cao et al, 2014;Chen et al, 2018;Luo et al, 2020;Vij et al, 2018;Wang et al, 2012;Wei et al, 2018;Zhai & Li, 2019). For example, Wei et al (2018) found within-network connectivity followed a negative quadratic (inverted U-shape) relationship from 20-80 years of age across the whole brain, starting to decline around 30 years, and accelerating from around 40 years of age.…”