Butler et al studied 159 case of chronic traumatic encephalopathy (CTE) and report that in the dorsolateral frontal cortex neuronal phosphorylated tau was significantly higher than astrocytic tau across all layers. Neuronal tau found mostly at the depth of sulci, including the pathognomonic perivascular distribution seen in CTE, was associated with age, years of repetitive head injury exposure and CTE severity. On the other hand, astrocytic tau was located primarily in the subpial regions and represents findings most consistent with aging-related tau astrogliopathy (ARTAG). The study supports the premise that neuronal tau is the major underlying pathological correlate of CTE.see page 773