Figure 1.

The four stages of chronic traumatic encephalopathy (CTE). In stage I CTE, isolated perivascular p-tau lesions are found in the cerebral cortex. In stage II CTE, multiple perivascular p-tau foci are found in the cerebral cortex. In the adjacent cortex, neurofibrillary tangles (NFTs) are scattered throughout the superficial cerebral layers. In stage III CTE, confluent patches of NFTs, neurites, and p-tau filled astrocytes are found around blood vessels at the sulcal depths and widely distributed throughout the cerebral cortex, including the medial temporal lobe. By stage IV CTE, p-tau pathology is densely distributed throughout the cerebrum, medial temporal lobe structures, brainstem, cerebellum, and occasionally, the spinal cord. Whole-mount sections of 50 µm are immunostained with CP-13.