MAPT and Alzheimer disease: In this study, we investigate the relationship between hyperphosphorylated pretangle tau and LTCC-mediated synaptic function by seeding pseudophosphorylated human 0N4R isoform of tau in the hippocampal cornu ammonis 1 (CA1), a structure that is selectively vulnerable to calcium dysregulation in Alzheimer’s disease patients and animal models.12 We found time-dependent changes of spatial learning, paralleled by alterations in neuronal and synaptic functions.