ABSTRACT FOR OVERVIEW The Aging Adult Brain Connectome (AABC) leverages the existing infrastructure developed by the Human Connectome Project for Aging (HCP-A) by obtaining longitudinal follow-up data (neuroimaging, cognitive testing, and blood) using a standardized protocol from a well characterized cohort of over 1,000 healthy individuals to generate within-participant brain trajectories for up to 10 years. At initial recruitment, individuals enrolled in the HCP-A were generally physically and cognitively healthy but over time some will develop preclinical AD or early cognitive changes due to AD or ADRD. The AABC is comprised of four Projects: Project 1 examine the effects of stress and allostatic load, including inflammation, during the early adult period. Project 2 examines the effects of lifestyle behaviors on the trajectory of cognitive and brain changes during the mid adult period. Project 3 examine the effects of menopause transition/vasomotor symptoms during the mid adult period. Project 4 exam- ine the clinical and neural indicators of resiliency and resistance to AD and ADRD in the later decades of adult- hood. The AABC also consists of 4 Cores: The Administration Core (AC) will provide essential core and site leadership to carry out the scientific mission of the AABC. The diversity recruitment and retention unit (DRRU) will be located within this core and will ensure that the AABC continues to recruit and retain an adequate distri- bution of races that is currently seen in the US. The Integrated Data Acquisition Core (IDAC) provides expertise and personnel from each site to acquire high quality neuroimaging, deep phenotyping of non-imaging data, and biosamples from each site.The Informatics, Data Analysis, and Statistics Core (IDASC) will house project imag- ing data using the IntraDB database, will perform quality control of raw and analyzed data, will develop and run cross-sectional and longitudinal pipelines to produce multi-modal imaging data phenotypes for each project, will provide dimension-reduced summaries, will impute missing data; and will develop and run statistical models for each project. The IDASC will also be responsible for data sharing with the general public. The Genetics and Multi-omics Specimens Core (GMSC) will provide genetic information on participants evaluated through the AABC who have been characterized using a uniform protocol. Multi-omic data and AD biomarker data will be generated by the GMSC.

NARRATIVE FOR OVERVIEW The Aging Adult Brain Connectome (AABC) builds on the existing infrastructure previously developed through the Human Connectome Project (HCP) Aging consortium. The AABC will acquire demographic, genetic, physi- ologic, health, and neurocognitive information in conjunction with cutting edge functional and structural neu- roimaging data (magnetic resonance imaging (MRI) and now magnetic resonance spectroscopy (MRS)) from a large cohort of individuals (n=1,000) across the lifespan. The overarching goal of the AABC is to determine structural and functional brain connectivity trajectories associated with vulnerability and resilience to develop- ing late life dementia. While cognitive decline and dementia are generally considered conditions of late life, the risk for developing late life impairment begins at conception and continues to accumulate throughout the lifespan.