C3AR1 and tauopathy: Specifically, understanding the cellular source of the upregulated central complement genes C2, C3, and C4a, as well as C1qa-c and C3ar1, will help elucidate the role of complement in delayed-onset neurocognitive deficits after TBI and in TBI-induced tauopathies implicated in Alzheimer-like pathology [55].