Format

Send to

Choose Destination
Front Aging Neurosci. 2015 Dec 24;7:237. doi: 10.3389/fnagi.2015.00237. eCollection 2015.

Age-Related Changes in Inter-Network Connectivity by Component Analysis.

Author information

1
Neuroscience Training Program, University of Wisconsin-MadisonMadison, WI, USA; Department of Radiology, University of Wisconsin-MadisonMadison, WI, USA.
2
Department of Radiology, University of Wisconsin-Madison Madison, WI, USA.
3
Department of Medicine, University of Wisconsin-Madison Madison, WI, USA.
4
Department of Psychiatry, University of Wisconsin-MadisonMadison, WI, USA; Department of Medical Physics, University of Wisconsin-MadisonMadison, WI, USA.
5
Neuroscience Training Program, University of Wisconsin-MadisonMadison, WI, USA; Department of Radiology, University of Wisconsin-MadisonMadison, WI, USA; Department of Medical Physics, University of Wisconsin-MadisonMadison, WI, USA; Department of Bio-Medical Engineering, University of Wisconsin-MadisonMadison, WI, USA.
6
Neuroscience Training Program, University of Wisconsin-MadisonMadison, WI, USA; Department of Radiology, University of Wisconsin-MadisonMadison, WI, USA; Department of Psychiatry, University of Wisconsin-MadisonMadison, WI, USA.

Abstract

Healthy aging is associated with brain changes that reflect an alteration to a functional unit in response to the available resources and architecture. Even before the onset of noticeable cognitive decline, the neural scaffolds underlying cognitive function undergo considerable change. Prior studies have suggested a disruption of the connectivity pattern within the "default-mode" network (DMN), and more specifically a disruption of the anterio-posterior connectivity. In this study, we explored the effects of aging on within-network connectivity of three DMN subnetworks: a posterior DMN (pDMN), an anterior DMN (aDMN), and a ventral DMN (vDMN); as well as between-network connectivity during resting-state. Using groupICA on 43 young and 43 older healthy adults, we showed a reduction of network co-activation in two of the DMN subnetworks (pDMN and aDMN) and demonstrated a difference in between-component connectivity levels. The older group exhibited more numerous high-correlation pairs (Pearson's rho > 0.3, Number of comp-pairs = 46) in comparison to the young group (Number of comp-pairs = 34), suggesting a more connected/less segregated cortical system. Moreover, three component-pairs exhibited statistically significant differences between the two populations. Visual areas V2-V1 and V2-V4 were more correlated in the older adults, while aDMN-pDMN correlation decreased with aging. The increase in the number of high-correlation component-pairs and the elevated correlation in the visual areas are consistent with the prior hypothesis that aging is associated with a reduction of functional segregation. However, the aDMN-pDMN dis-connectivity may be occurring under a different mechanism, a mechanism more related to a breakdown of structural integrity along the anterio-posterior axis.

KEYWORDS:

ICA; aging; dedifferentiation; default-mode network; fMRI; functional connectivity

Supplemental Content

Full text links

Icon for Frontiers Media SA Icon for PubMed Central
Loading ...
Support Center