Imaging the Human Reward System Across the Adult Life Span

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DESCRIPTION (provided by applicant): Increases in human life expectancy over the twentieth century will continue to expand the proportion of older adults in the global population, magnifying the relative economic impact of their health-related and financial decisions. Thus, it is increasingly imperative to better characterize and understand age-related changes in reward processing and decision making across the adult life span. New in vivo brain imaging techniques using magnetic resonance imaging (MRI) and positron emission tomography (PET) now allow more precise measurement of the human reward system. Highly detailed visualization of structures across the brain is now possible using ultra high field strength 7-Tesla MRI scanners. The use of high-resolution protocols (i.e., slice prescriptions that selectively measure a subsection of the brain) at high field strength has the potential to both structurally and functionally dissociate individual nuclei in the reward system. Measurement of dopamine receptor availability in both striatal and extrastriatal (e.g., midbrain, frontal cortical) regions is now possible using the radioligand [18F]fallypride in PET imaging. These imaging techniques facilitate previously unavailable in-depth measurement across the brain. The main objective of this fellowship grant is to train the applicant in the use of novel methods for imaging the human reward system across the adult life span. Training will also include broadening the applicant's base of knowledge through directed reading, honing teaching and mentoring skills, and building laboratory and grant management skills to ensure productivity and success throughout the applicant's career. The specific aims are to train the applicant to (1) use high-resolution, ultra high field strength, (7-Tesla) MRI to examine structural and functional age-related changes in individual subregions of the midbrain across adulthood, (2) combine [18F]fallypride PET and functional MRI to characterize associations between dopamine receptor availability and aspects of reward processing and behavioral control in healthy adults, and (3) integrate structural (MRI) and functional (PET, fMRI) measures of neural integrity to investigate age-related changes in decision making from young adulthood to middle age. The goal of all aims is to precisely characterize the neural changes underlying age-related changes in cognition, specifically related to decision making and behavioral control. The fellowship will support the next stage of training on the applicant's path to becoming an independent psychological scientist in the cognitive neuroscience of aging. After completion of training, the applicant's goal is to combine these new methods to not only more precisely quantify age-related change in the human reward system but also to investigate the implications of these changes throughout the adult life span. The long-term goal of the applicant's career is to conduct basic scientific research that contributes directly to interventions aimed at easing the cognitive strain and improving emotional and economic health in the daily lives of aging adults. PUBLIC HEALTH RELEVANCE: This research training plan aims to use cutting edge neuroimaging technology to expand understanding of processes underlying decision making and behavioral control over the adult life span. This work has the potential to facilitate identification of markers for suboptimal decisions in older adults in order to inform the design of appropriate interventions. The long-term goal of this line of research is to improve the financial and emotional health of older adults by improving decision making at the individual level.