MAPT and Alzheimer disease: It is therefore possible that amyloid and Tau accumulation in the hippocampus modify the transmission between the hippocampus and the striatum, resulting in a decrease of dopamine release which would generate an up-regulation of postsynaptic D2/3R. This hypothesis is consistent with a previous study demonstrating that homozygous 3xTg-AD mice display a decrease of cortical dopamine release at 10-month-old that was not present at 3-month-old.