Figure 2

Microscopic neuropathology of CTE. Top panel: Phosphorylated tau (AT8) immunostained coronal hemisections of a normal brain (left) and a brain from a retired professional football player with CTE (right). The brain with CTE displays severe neurofibrillary degeneration of the amygdala (a), entorhinal cortex (ec), temporal cortex, insular cortex (ins), nucleus basalis of Meynert (nbM), and frontal cortex. The cortical changes are more pronounced at the depths of the sulci. Lower panels: (A) AT8-positive neurofibrillary tangles (NFTs) are often prominent at the depths of the cortical sulci (original magnification: ×60). (B) Subpial AT-8- immunoreactive tangles are found in both neurons and astrocytes (double-immunostained section for GFAP (red) and AT8 (brown), showing colocalization of tau and GFAP; ×350). (C) Dense AT8-NFTs are found in the medial temporal lobe, including the CA1 region of the hippocampus, shown here. (×150). (D) AT-8-positive NFTs and astrocytic tangles tend to be centered around small blood vessels and in subpial patches (×350). (E) NFTs characteristically involve cortical layers II and III (×150). (F) NFT in a Betz cell of the primary motor cortex (×350). (G) Perivascular tau-immunoreactive NFTs in CTE (×150). Reprinted with permission from Stern et al. 2011 (Stern et al. 2011).