Neurodegeneration as Convergent Pathway Failure: A Three‑System Framework Explaining Late‑Life Decline

Neurodegenerative diseases are not a natural consequence of aging, and understanding their etiology is essential for effective treatment or prevention. This manuscript proposes that neurodegeneration arises from a convergence of stress across three systems that work together to maintain brain health: mitochondrial function, protein and waste management, and neuroimmune regulation. While several environmental and systemic stressors — such as pesticides, sleep disruption, and vascular insufficiency — have been identified as contributing to neurodegeneration, this article examines whether frequent head exposure to low‑dose diagnostic radiation may incrementally tax these critical pathways over the years. Medical and dental exposure to ionizing radiation is presented as an illustration of how modern practices may contribute to cognitive decline. This systems-view reframes neurodegenerative risk as measurable beyond genetic contributions and potentially modifiable, opening the door to individualized assessment and targeted mitigation.