Aging As a Random Walk: Quantifying Unsystematic Effects of Aging On the Brain’s Architecture
The brain exhibits degenerative changes during later life which contribute to cognitive impairment. Most previous work has examined systematic effects of aging on features of the brain, such as cumulative volume loss at particular brain regions (e.g., hippocampus). In contrast, unsystematic, random changes with aging are far less investigated. We propose that during later life, the neural substrates that maintain the brain’s structural and functional organization exhibit generalized attrition. As a result, like the accumulation of random point mutations in the genome with age, there is accumulation of random point perturbations in the brain’s structural and functional architecture. Detecting and quantifying these age-induced perturbations is challenging and requires the development of novel statistical methods. In this project, we leverage a number of large publicly shared neuroimaging datasets in order to develop a statistical toolkit for quantifying these unsystematic brain changes. Our overarching aim is to link the total load of unsystematic perturbations in brains to cognitive impairment and dementia risk.