MAPT and Cognitive impairment: A following study by the Rissman group found that plasma-derived neuronal exosomal levels of pT181-tau, pS396-tau, and Aβ42 were increased, whereas the post-synaptic protein neurogranin and repressor element 1-silencing transcription factor (REST) levels were decreased in patients with AD or with mild cognitive impairment (MCI) converting to AD compared to normal subjects and patients with stable MCI that did not convert to AD (Winston et al., 2016).