This K23 resubmission is for Dr. Dzierzewski, an Assistant Professor in the David Geffen School of Medicine at UCLA, who is fully committed to becoming an independently-funded investigator studying the impact of health behaviors on late-life cognitive functioning. He has a particular interest in modifiable risk factors and biological correlates of cognitive difficulties in older adults. His unique background makes him an ideal candidate for this field of research. Dr. Dzierzewski has graduate, internship, and fellowship-level clinical and research training in both geropsychology/geriatrics and sleep in late-life. He i currently supported by an Advanced Fellowship in Geriatrics through the VA's Geriatric Research, Education, and Clinical Center and UCLA's Claude D. Pepper Center during which he is conducting original research on the cognitive correlates of disturbed sleep in late-life. Career development and training plan: Dr. Dzierzewski's training plan couples an outstanding research and education environment at UCLA with nationally renowned expert mentors. His primary mentoring team is comprised of Drs. Jennifer Martin (expert in sleep in late-life), Cathy Alessi (expert in sleep interventions and interventions to promote independence in older adults), Michael Irwin (expert in inflammatory processes and sleep), and Gary Small (expert in methods to improve late-life cognitive functioning). He will also draw on resources available through UCLA's CTSI, UCLA's Multicampus Program in Geriatric Medicine and Gerontology, UCLA's Claude D. Pepper Center, and the VA Greater Los Angeles Healthcare System GRECC. His training plan features carefully designed coursework and hands-on training experiences. Research plan: Decreased cognitive functioning and the concomitant loss of function are negative consequences of the aging process. Identifying modifiable risk factors for cognitive and functional decline among older adults is critical to designing the most effective means of intervention. Dr. Dzierzewski's research aims to investigate the cognitive and inflammatory sequelae of comorbid sleep apnea and insomnia in late-life (the most prevalent sleep disorders in older adults), along with the cognitive and inflammatory responses of improvements in sleep. The proposed research is hypothesis driven and guided by a model of sleep and cognition. The application focuses on the cross-sectional (Aim 1) and longitudinal relationships (Aims 1.1, 2 & 2.1) between sleep, inflammatory factors, and cognitive functioning in a sleep disordered sample of older adults with comorbid sleep apnea and insomnia, and in a non-sleep disordered sample of older adults. A unique aspect of the proposed work is its focus on inflammatory factors as potential explanatory mechanisms. It is expected that each Aim will result in published manuscripts and data which will directly inform and shape future R01-applications. This training and research plan will enable Dr. Dzierzewski to become an independent researcher and leader in the impact of health behaviors, specifically sleep, on late-life cognitive functioning.