Hub architecture of the human structural connectome: Links to aging and processing speed

Abstract

The human structural brain network, or connectome, has a rich-club organization with a small number of brain regions showing high network connectivity, called hubs. Hubs are centrally located in the network, biological costly, and might be critical for human cognition. Normal aging is accompanied by cognitive decline, including processing speed, and has been linked to energy depletion in the neurons at a molecular level. However, it is still unclear how age affects hub connections in human connectome. Using a large healthy sample (N=137) with wide age range (25-85 years), we found that the anatomical locations of hubs are relatively age-invariant. However, there were wide-spread age effects on the connectivity strength in the connectome. Critically, these age effects were larger in connections within hubs compared to more peripheral brain regions. These findings were supported by both cross-sectional and longitudinal (N=83) analyses. Moreover, results demonstrated associations between connectivity strength and processing speed, which were more concentrated in hub connections than chance level, and the connectivity strength in hub connections mediated the age-effects on processing speed. Overall, our findings indicate that the hub connections are especially affected by aging, and their vulnerability to the age effects might explain the lower processing speed in older adults.

Modeling the neurocognitive dynamics of language across the lifespan

“…Overall, our model shows a transition occurring in midlife within the language connectome, that is a shift from a more “energy‐intensive” (costly) dynamic of compensation to a more “energy‐efficient” one. Indeed, our research indicates that younger adults are more capable of accommodating the metabolic demands associated with sustaining long‐range neural connections (Li et al, 2023; Liang et al, 2013; Tomasi et al, 2013). In comparison, older adults seem to adopt a more “energy‐efficient” approach, substituting the reallocation of long‐range connections between subsystems with short‐range connections within subsystems, thus lowering the metabolic demands needed to achieve compensatory integration.…”

Lifespan Oscillatory Dynamics in Lexical Production: A Population-based MEG Resting-State Analysis

“…Relatedly, sensorimotor information (States 4-5) was more often redirected along a posterior route via visuo-occipital areas (States 3-6) to dorso-posterior states where DMN converges with lower-level circuitry (States 2 and 8). Acute engagement of the visuo-occipital regions in the alpha-band may thus facilitate information flow between sensorimotor and dorso-posterior DMN in older adulthood, hypothetically lowering the metabolic demands of maintaining long-distance functional connections 88 .…”

Single‐subject cortical morphological brain networks across the adult lifespan

“…Compared with non-hubs, hubs are more densely interconnected, forming a rich-club organization (van den Heuvel & Sporns, 2011). Previous studies of structural brain networks found that connections of hubs were disproportionately influenced by development and aging (Baker et al, 2015;Li et al, 2023). In parallel, a recent study found that genes played a preferential role in shaping the connections between hubs (Arnatkeviciute et al, 2021).…”