Aging brains show more complex and less stable electrical activity, while Alzheimer's disease collapses both—new research reveals a potential early marker for neurodegeneration.
The research
Junjie Yu and colleagues from Southern University of Science and Technology and other institutions analyzed EEG data from multiple datasets, including multi-task, lifespan, and clinical cohorts. They modeled EEG signals as distributions of short activity patterns and measured two things: intrinsic dimensionality (how complex the patterns are) and temporal stability (how similar patterns remain over time). Across all datasets, they found that neural activity does not drift randomly but shows constrained, condition-specific stability. Crucially, higher complexity was consistently linked to lower stability—richer neural representations are less reproducible. Both measures showed a clear spatial pattern: posterior brain regions had higher complexity and lower stability than frontal regions.
In healthy aging, complexity increased while stability decreased. In contrast, mild cognitive impairment (MCI) and Alzheimer's disease (AD) showed a simultaneous collapse of both complexity and stability. This distinction suggests that the normal aging process may be characterized by a trade-off between complexity and stability, but neurodegeneration disrupts both.
Why it matters
These findings offer a new framework for tracking cognitive health. The joint collapse of complexity and stability in MCI and AD could serve as a sensitive biomarker for early detection and monitoring. For healthy individuals, the results highlight that some cognitive decline in aging is natural, but a sudden drop in both measures might warrant clinical attention. This could lead to earlier interventions and better management of neurodegenerative diseases.
What you can do
While this is early-stage research, you can support your brain health by engaging in activities that promote cognitive diversity and stability: learning new skills, staying socially active, and maintaining a healthy lifestyle. Regular mental stimulation may encourage flexible yet stable neural patterns. Stay curious and keep challenging your brain—it's one of the best ways to maintain cognitive vitality.
Source: arXiv q-bio.NC
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