MAPT and neurodegenerative disease: In humans, tau and amyloid aggregation are thought to be important drivers of pathology after TBI and in neurodegenerative diseases more generally.8,10,11 Since murine tau and amyloid do not aggregate under pathological conditions as their human homologs do,12,13 the use of knockin mice carrying humanized versions of these genes13,14 better models these pathological features.