The current study will investigate methods for enhancing cognitive training effects in healthy older adults by employing a combination of interventions facilitating neural plasticity and optimizing readiness for learning. Adults over the age of 65 represent the fastest growing group in the US population. As such, age-related cognitive decline represents a major concern for public health. Recent research suggests that cognitive training in older adults can improve cognitive performance, with effects lasting up to 10 years. However, these effects are typically limited to the tasks trained, with little transfer to other cognitive abilities or everyday skills. An adaptive pilot randomized clinical trial will examine the individual and combined impact of pairing cognitive training with transcranial direct current stimulation (tDCS). tDCS is a method of non-invasive brain stimulation that directly stimulates brain regions involved in active cognitive function and enhances neural plasticity when paired with a training task. We will compare changes in cognitive and brain function resulting from CT and CT combined with tDCS using a comprehensive neurocognitive, clinical, and multimodal neuroimaging assessment of brain structure, function, and metabolic state.