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Related Experiment Video

Updated: May 30, 2026

Developing Neuroimaging Phenotypes of the Default Mode Network in PTSD: Integrating the Resting State, Working Memory, and Structural Connectivity

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Imaging the default mode network in aging and dementia.

Anne Hafkemeijer¹, Jeroen van der Grond, Serge A R B Rombouts

¹Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands. A.Hafkemeijer@lumc.nl

Biochimica Et Biophysica Acta

|August 3, 2011

Summary

Brain imaging reveals that normal aging and Alzheimer's disease (AD) impair the default mode network (DMN). Both functional connectivity and task-induced deactivations within the DMN are reduced, even in those at high risk for AD.

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Area of Science:

Neuroscience
Medical Imaging
Gerontology

Background:

Task-activation fMRI traditionally focused on brain activation.
Growing interest exists in task-induced brain activity decreases (deactivations) within the default mode network (DMN).
Resting-state fMRI studies explore spontaneous activity and functional connectivity in the DMN.

Purpose of the Study:

To review the impact of normal aging and dementia on DMN task-induced deactivations and functional connectivity.
To assess changes in the DMN across a continuum from healthy aging to Alzheimer's disease (AD).

Main Methods:

Review of existing task-activation and resting-state fMRI studies.
Analysis of DMN functional connectivity and task-induced deactivations.
Inclusion of studies on individuals at risk for AD (amyloid plaques, APOE4 allele).

Main Results:

Most studies indicate decreased DMN functional connectivity and task-induced deactivations in normal aging, mild cognitive impairment, and AD.
Disruptions in the DMN are evident even in individuals at high risk for AD.
fMRI shows potential for detecting DMN changes but requires further validation for clinical AD diagnosis.

Conclusions:

Aging and dementia, including AD, are associated with reduced DMN functional connectivity and deactivations.
These DMN alterations are observable even in preclinical stages and in individuals with genetic risk factors for AD.
While fMRI is a valuable research tool for DMN changes, its utility as a standalone clinical diagnostic tool for AD needs further investigation.