A Review of Normal Brain Aging: Detailed Study of Physiological Changes, Risk Factors, and Neuroimaging Techniques

Introduction: The process of brain aging is a complex phenomenon that can manifest in a number of ways, including normal, pathological, and accelerated aging, each influenced by modifiable factors such as sex and lifestyle. Subtle, preclinical alterations, including iron accumulation, proteostasis disruption, and inflammation, often precede overt clinical manifestations of cognitive decline, highlighting the need for early detection and intervention.Material and Methods: This review examines the neuropathological mechanisms of age-related cognitive decline, integrating current knowledge on the interplay of genetic, environmental, and lifestyle factors. Advanced neuroimaging techniques, particularly magnetic resonance imaging (MRI) and positron emission tomography (PET) offer powerful tools for investigating the complex biological and biochemical dynamics of the aging brain. Quantitative Susceptibility Mapping (QSM), a novel MRI technique, provides precise quantification of tissue magnetic susceptibility, enabling detailed assessment of iron deposition and myelin content, both crucial factors in age-related brain changes.Results: We explore the diagnostic potential of QSM and other advanced neuroimaging techniques for identifying early biomarkers of brain aging and predicting cognitive trajectories. This research indicates that the accumulation of non-heme iron is a primary contributor to neuronal death in brain aging. This conclusion is supported by QSM studies, which have validated the role of iron in this process.Conclusion: By integrating mechanistic understanding with practical prevention strategies, this research indicates that the accumulation of non-heme iron is a primary contributor to neuronal death in brain aging. Additionally, the literature suggests that dietary and physical activity interventions may beneficially mitigate neurodegeneration associated with aging.