Approximately 5.8 million adults age 60 and over in the United States live with Alzheimer disease and related dementias (AD/ADRD) at a cost of $290 billion per year. Older adults with mild cognitive impairment (MCI), an intermediate stage between typical aging and dementia, are 3-5 times more likely to progress to AD than those with normal cognition. Late-life engagement in cognitively challenging activities is associated with decreased risk of cognitive decline, and there is a need to address cognitive inactivity. Music interventions are a promising strategy to address late-life cognitive inactivity. Music training can change brain structure and function in non-musician adults, thereby leading to cognitive, perceptual, and psychosocial advantages. These changes in cognitive function are thought to occur because the multimodal, complex nature of music facilitates training-induced neural plasticity. However, the mechanisms are not yet understood, and most studies used traditional or rote keyboard training techniques. Music training based on improvisation principles-the spontaneous generation of musical melodies and rhythms-will likely have more potent effects on cognition and brain function. Improvisation facilitates cognitive flexibility, self-monitoring, novel idea generation, execution of unplanned motor sequences and entrance into a state of flow. Biologically, improvisation is associated with distinct neural patterns involving activation of prefrontal networks and other brain networks that are affected by aging. As a mechanism of behavior change, it is likely that improvisation training will uniquely improve self-regulation (the ability to monitor and control one's own behavior, emotions, or thoughts and modify to situational demands). Yet, no research has tested whether improvisation training can improve self-regulation and facilitate maintenance of cognitively challenging activities among older adults with and without MCI. This project will develop and test the effects and mechanisms of a music improvisation training intervention on self-regulation of older adults with and without MCI. Our overall hypothesis is that improvisation training will lead to improvements in self-regulation, compared to controls, and that improvisation training will be associated with specific changes in prefrontal brain networks and ultimately cognitive engagement. Our project has two phases. In the R61 phase, the study will develop a music improvisation training intervention that aims to improve self-regulation among older adults with and without MCI and conduct a 2-arm randomized pilot study to (i) examine feasibility and acceptability of the intervention and study methods and (ii) determine its effects on the hypothesized mechanism of self-regulation. If milestones are met, the study will proceed to the R33 phase and conduct a randomized mechanistic trial to examine the effects of the intervention, compared to an attention control, on self-regulation and cognitive engagement among older adults with and without MCI. The findings from this study will improve our understanding of the underlying mechanisms of how music training interventions can facilitate behavior change to maintain health of older adults.