Since p-Tau and other forms of toxic Tau are part of exosome cargo and can be spread in the brain via exosomes (Figure 2 and [114]), we conducted experiments in which neuron-derived exosomes (NDEs) were purified from DS–AD plasma and injected into the dorsal hippocampus of a wild-type mouse (WT) with stereotaxic techniques (Figure 3 and [21]). Here, MAPT is linked to Alzheimer disease.