Histopathologic features of chronic traumatic encephalopathy in a former professional football player (courtesy of Ann McKee, MD, Center for the Study of Traumatic Encephalopathy, Boston University School of Medicine, Boston, Massachusetts). A, Scanning view of the hippocampus and parahippocampal cortex. Note intense immunostaining of the entire Ammon horn and subiculum with focal involvement at the depths of sulci of the inferior temporal lobe. B, Appearance of individual neurofibrillary tangles in the neocortex. C, Predilection for neurofibrillary tangle involvement in the superficial layers (layers II/III) (as opposed to deeper layers [layers V/VI], as is more common in Alzheimer disease) of the anterior insular cortex. D, Tendency for perivascular tau deposition and neurofibrillary tangle formation in the frontal cortex. All sections immunostained for abnormally phosphorylated tau (AT-8, monoclonal antibody that detects hyperphosphorylated tau, serine 202, and threonine 205). A, Original magnification ×1. B, Original magnification ×160. C, Original magnification ×30. D, Original magnification ×60.