Traumatic coma is associated with disruption of axonal pathways throughout the brain but the specific pathways involved in humans are incompletely understood. In this study, we used high angular resolution diffusion imaging (HARDI) to map the connectivity of axonal pathways that mediate the 2 critical components of consciousness – arousal and awareness – in the postmortem brain of a 62-year-old woman with acute traumatic coma and in 2 control brains. HARDI tractography guided tissue sampling in the neuropathological analysis. HARDI tractography demonstrated complete disruption of white matter pathways connecting brainstem arousal nuclei to the basal forebrain and thalamic intralaminar and reticular nuclei. In contrast, hemispheric arousal pathways connecting the thalamus and basal forebrain to the cerebral cortex were only partially disrupted, as were the cortical “awareness pathways.” Neuropathologic examination, which utilized β-amyloid precursor protein and fractin immunomarkers, revealed axonal injury in the white matter of the brainstem and cerebral hemispheres that corresponded to sites of HARDI tract disruption. Axonal injury was also present within the grey matter of the hypothalamus, thalamus, basal forebrain, and cerebral cortex. We propose that traumatic coma may be a subcortical disconnection syndrome related to the disconnection of specific brainstem arousal nuclei from the thalamus and basal forebrain.