Reduced functional segregation between the default mode network and the executive control network in healthy older adults: A longitudinal study
Kwun Kei Ng, June C. Lo, Joseph K.W. Lim, Michael W.L. Chee, Juan Zhou
NeuroImage March 19, 2016 DOI: 10.1016/j.neuroimage.2016.03.029 via OpenAlex
Summary
AI-generated from the abstractIn healthy older adults, functional connectivity within brain networks (executive control and default mode networks) declines over four years, indicating a loss of functional specialization with aging. Between these networks, connectivity initially increases (greater segregation) but later decreases, following a u-shaped trajectory. The rate of this later loss in segregation is linked to a decline in processing speed. These brain connectivity changes are independent of gray matter volume loss. The findings connect age-related changes in brain network function to age-related cognitive decline.
Study at a glance
| Characteristics | Longitudinal cohort study Cross-sectional Peer reviewed |
|---|---|
| Sample size | 78 |
| Population | Healthy older adults |
| Duration | 4 years |
| Citations | 237 |
| Key finding | Longitudinal changes in functional connectivity within and between the executive control and default mode networks are associated with age-related decline in processing speed. |
Abstract
The effects of age on functional connectivity (FC) of intrinsic connectivity networks (ICNs) have largely been derived from cross-sectional studies. Far less is known about longitudinal changes in FC and how they relate to ageing-related cognitive decline. We evaluated intra- and inter-network FC in 78 healthy older adults two or three times over a period of 4years. Using linear mixed modeling we found progressive loss of functional specialization with ageing, evidenced by a decline in intra-network FC within the executive control (ECN) and default mode networks (DMN). In contrast, longitudinal inter-network FC between ECN and DMN showed a u-shaped trajectory whereby functional segregation between these two networks initially increased over time and later decreased as participants aged. The rate of loss in functional segregation between ECN and DMN was associated with ageing-related decline in processing speed. The observed longitudinal FC changes and their associations with processing speed remained after correcting for longitudinal reduction in gray matter volume. These findings help connect ageing-related changes in FC with ageing-related decline in cognitive performance and underscore the value of collecting concurrent longitudinal imaging and behavioral data.