SNAP25 and Mental deterioration: Together with SNAP-25, CSF levels of the presynaptic protein SYT-1 and the postsynaptic NG are increased in early stages of the Alzheimer’s disease continuum and correlate with cognitive decline, Aβ and tau pathology.5,28,33,34 In our study, NG levels were increased in A+ individuals and tended to be elevated in Alzheimer’s disease patients (though not significantly, P = 0.084), while SYT-1 did not vary across the three clinical groups.