MAPT and Cognitive impairment: Importantly, neither cognitive deficits nor the increase in glutamate release and VGlut1 levels were observed in the rTg(TauWT)21221 mouse model that expresses wild-type 4R0N human tau at concentrations equivalent to P301L human tau in tauP301L pos mice, but without the P301L mutation and associated tau pathology (Hunsberger et al., 2014).