Cited by 968Alzheimer's disease research and treatmentsDementia and Cognitive Impairment ResearchNeurogenesis and neuroplasticity mechanisms

Age-related myelin breakdown: a developmental model of cognitive decline and Alzheimer’s disease

Bartzokis, George·2004·Neurobiology of Aging

Abstract

A hypothetical model of Alzheimer's disease (AD) as a uniquely human brain disorder rooted in its exceptional process of myelination is presented. Cortical regions with the most protracted development are most vulnerable to AD pathology, and this protracted development is driven by oligodendrocytes, which continue to differentiate into myelin producing cells late into the fifth decade of life. The unique metabolic demands of producing and maintaining their vast myelin sheaths and synthesizing the brain's cholesterol supply make oligodendrocytes especially susceptible to a variety of insults. Their vulnerability increases with increasing age at differentiation as later-differentiating cells myelinate increasing numbers of axonal segments. These vulnerable late-differentiating cells drive the protracted process of intracortical myelination and by increasing local cholesterol and iron levels, progressively increase the toxicity of the intracortical environment forming the basis for the age risk factor for AD. At older ages, the roughly bilaterally symmetrical continuum of oligodendrocyte vulnerability manifests as a progressive pattern of myelin breakdown that recapitulates the developmental process of myelination in reverse. The ensuing homeostatic responses to myelin breakdown further increase intracortical toxicity and results in the relentless progression and non-random anatomical distribution of AD lesions that eventually cause neuronal dysfunction and degeneration. This process causes a slowly progressive disruption of neural impulse transmission that degrades the temporal synchrony of widely distributed neural networks underlying normal brain function. The resulting network "disconnections" first impact functions that are most dependent on large-scale synchronization including higher cognitive functions and formation of new memories. Multiple genetic and environmental risk factors (e.g. amyloid beta-peptide and free radical toxicity, head trauma, anoxia, cholesterol levels, etc.) can contribute to the cognitive deficits observed in aging and AD through their impact on the life-long trajectory of myelin development and breakdown. This development-to-degeneration model is testable through imaging and post mortem methods and highlights the vital role of myelin in impulse transmission and synchronous brain function. The model offers a framework that explains the anatomical distribution and progressive course of AD pathology, some of the failures of promising therapeutic interventions, and suggests further testable hypotheses as well as novel approaches for intervention efforts.

Integrity signals

Registry

Crossref · 10.1016/j.neurobiolaging.2003.03.001

Cites

274 of 274 references verified0 citation errors · 0 not checkable

Statistics

Recomputing p-values needs the paper’s full text.

Claims the paper makes

This paper’s full text isn’t openly available, so its claims and self-check weren’t run. The registry and citation checks still apply.

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

Cites

Flagged first, then by citations

Cited by

Sorted by citations

Authors
Bartzokis, G.
Affiliations
University of California, Los Angeles (US)
Corresponding author
Bartzokis, George
Venue
Neurobiology of Aging
Publisher
Elsevier BV
Published
2004-01
Volume
25
Issue
1
Pages
5-18
ISSN
0197-4580 (ISSN-L)
OpenAlex
W1981000616
Cited by
968
References
274
Citations by year
2026: 31 · 2025: 37 · 2024: 49 · 2023: 40 · 2022: 50 · 2021: 46 · 2020: 50 · 2019: 48 · 2018: 40 · 2017: 47 · 2016: 42 · 2015: 48 · 2014: 40 · 2013: 58 · 2012: 43
FWCI
3.43
Type
journal article
Language
en
Open access
closed
Locations
  • Neurobiology of Aging (publishedVersion)
  • PubMed (publishedVersion)
Funders
  • National Institute on Aging (P50AG016570, AG 16570)
  • National Institute of Mental Health (MH6357-01A1)
Topics
  • Health Sciences › Medicine › Physiology › Alzheimer's disease research and treatments
  • Health Sciences › Medicine › Psychiatry and Mental health › Dementia and Cognitive Impairment Research
  • Life Sciences › Neuroscience › Developmental Neuroscience › Neurogenesis and neuroplasticity mechanisms
Keywords
Alzheimer's disease, myelination, oligodendrocytes, myelin breakdown, cognitive decline, brain aging, cortical development, cholesterol, iron, neuronal synchronization, memory impairment, amyloid-beta, free radical toxicity, head trauma, anoxia
MeSH terms
Aging, Alzheimer Disease, Animals, Brain, Cognition Disorders, Disease Models, Animal, Humans, Myelin Sheath, Neurons, Oligodendroglia, Risk Factors, Cell Death

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

Are you an author, or do you see a problem with this page? Request a review