Default Mode Network and Neural Phase Synchronization in Healthy Aging: A Resting State EEG Study
Ricky Chow, Rahel Rabi, Shahier Paracha, Lynn Hasher, Nicole D. Anderson, Claude Alain
Neuroscience January 17, 2022 DOI: 10.1016/j.neuroscience.2022.01.008 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Observational cohort Peer reviewed |
|---|---|
| Sample size | 89 |
| Population | Younger adults (18-30 years) and older adults (64-88 years) |
| Measures | phase-locking value (PLV) |
| Topics | Default mode network |
| Keywords | Electroencephalography Phase synchronization Resting State FMRI Synchronization alternating current Functional connectivity Audiology Phase matter |
| Citations | 23 |
| Key findings | Older adults showed decreased alpha2 band phase-locking value (PLV) between the medial prefrontal cortex and left angular gyrus and bilateral lateral temporal cortices, which correlated with lower semantic fluency and executive functioning. Increased theta and beta PLV between medial prefrontal cortex and posterior cingulate was also found in older adults, indicating non-uniform, frequency-dependent changes in DMN connectivity. |
Abstract
Aging is associated with altered brain connectivity within the default mode network (DMN). Although research using functional magnetic resonance imaging has quantified age-related alterations in functional connectivity within this network during resting state, it is less clear how this may be reflected in electrophysiological measures, and how this relates to cognitive performance in older adults. The aim of this study was to quantify age differences in phase synchrony of the DMN during resting state, with particular focus on connectivity between the anterior node (i.e., medial prefrontal cortex, or mPFC) and other associated regions in this network. Electroencephalography was recorded from 55 younger adults (18-30 years, 28 females) and 34 older adults (64-88 years, 16 females) in two resting state conditions (eyes-open and -closed). Source-level functional connectivity was quantified using phase-locking value (PLV) with a spatial filter of six sources of interest, and were subjected to data-driven permutation testing between groups from 1 to 50 Hz. Older adults also completed tests of memory, language, executive functioning, and processing speed. Findings indicated decreased connectivity in the alpha2 range for older than younger adults between the mPFC and other DMN regions including the left angular gyrus and bilateral lateral temporal cortices, the latter of which were associated with lower performance in semantic fluency and executive functioning in older adults. Furthermore, greater PLV in theta and beta bands between the mPFC and posterior cingulate regions were found in older than younger adults. These results suggest age-related changes in DMN functional connectivity are non-uniform and frequency-dependent, and may reflect poorer performance in cognitive domains thought to decline with aging.