Older adults experience slowed processing speed and the severity of slowed processing speed is a strong predictor of age-related cognitive decline and independence.  In our recent manuscript in the journal Frontiers in Neuroscience we review the structural changes observed in brains of older adults that occur with slowed processing speed.  The most consistently observed structural changes occur in frontal brain regions that are susceptible to micro-vascular disease and cerebellar regions that together appear to constitute declines in neural systems important for coordinating and adapting behavior.  Frontal/cerebellar systems may therefore be targets for understanding the efficacy of interventions designed to enhance healthy aging.