Myelin is the fatty insulation that allows for rapid communication between brain regions. This hypothesis suggests that soluble amyloid-beta oligomers (clumps) are toxic to the cells that produce and maintain myelin (oligodendrocytes). This disruption of white matter integrity in the cortex may be one of the very earliest events in Alzheimer's, occurring before significant plaque buildup or memory loss, and could be detectable with advanced imaging.

Biological Mechanism:

Myelin, the fatty insulation around nerve fibers, enables rapid communication between brain regions. Produced by oligodendrocytes, it is vulnerable to soluble amyloid-beta oligomers even before plaques form.

In early Alzheimer's, amyloid-beta disrupts oligodendrocyte function, triggering cortical myelin degradation. This myelin breakdown slows neural transmission, impairs network synchronization, and precedes neuronal loss by years.

Damaged myelin releases lipids that activate microglia, creating neuroinflammation that further degrades myelin a feed-forward loop. Preserving myelin integrity maintains circuit function, delays symptom onset, and may prevent irreversible axonal damage. Myelin-protective agents target oligodendrocyte survival and repair mechanisms, intervening at the earliest detectable stage of disease.