Project Summary CNS glial cells, including oligodendrocytes, astrocytes and microglia, regulate neuronal function. Although much is known about their importance in the developing and adult CNS, a gap in knowledge remains with regards to how aged glia contribute to remyelination failure and neurodegeneration. This is particularly relevant to age related neurodegenerative disorders, such as secondary progressive multiple sclerosis (MS), Alzheimer’s disease (AD), and Parkinson’s disease (PD) in which glial dysfunction and chronic inflammation within the CNS, are common features. In order to fully understand the impact of aged glia on CNS function, the goal of this project is to characterize novel models of CNS glial senescence in mice and examine their impact on CNS function and repair.