Project Summary/Abstract Traumatic brain injury (TBI) is a global concern that precipitates a diverse set of health consequences. TBI is a major concern in forensic populations -- an issue recently highlighted by calls for research by national public health institutions [1]. Indeed, upwards of 60% of inmates have a history of TBI, a rate seven times higher than the general population (8.5%) [2, 3]. TBI is a criminogenic risk factor [3, 4] and even mild TBI increases the rates of risk-taking behavior, substance use, and future offending [2, 4]. Over the last decade our team has been continuously funded by NIH to collect detailed clinical and neuroimaging protocols from over 4000 incarcerated men and women. We utilize a unique pair of twin mobile MRI units that are deployed directly on the secure grounds of forensic facilities, making it possible to conduct this research. Our dataset includes multimodal neuroimaging protocols, thorough clinical assessment, neuropsychological evaluations, and histories of TBI. All of our n>4000 offenders have consented to participate in longitudinal follow-up studies. For this project, we will commence a longitudinal study on n=300 individuals aged 35+, examining variables that will differentiate trajectories associated with cognitive impairments. We will also leverage advanced neuroimaging tools developed by our team to provide brain-based measures of cognitive decline and imaging-based classification tools for identifying brain injuries and comorbid conditions (i.e., substance abuse, psychopathy scores, depression, etc.). We will also examine how the brain injury profiles and comorbid conditions change over time. The availability of these unique resources to examine this highly underserved population makes this an exciting project with the potential to break new ground in our understanding of individual risk needs and divergent outcomes in TBI and neurodegenerative disease.