Kochsiek J, O'Donnell LJ, Zhang F, et al. - This retrospective cohort study was undertaken to determine if repetitive head impacts (RHI) exposure is correlated with later-life corpus callosum (CC) microstructure and whether CC microstructure is related to plasma total tau and neuropsychological/neuropsychiatric functioning. Participants in the study were 75 former professional American football players (age 55.2 ± 8.0 years) with cognitive, behavioral, and mood symptoms. Findings point to a link between RHI exposure, CC microstructure, plasma total tau, and clinical functioning in ex-professional American football players.