SYP and Alzheimer disease: Although Aβ1-42 is considered to be the major neurotoxin generated in AD [47-50] other Aβ fragments are produced [24,25,51] and since Aβ1-40 is the predominant Aβ species formed in AD [29,52] the effect of Aβ1-40 on αSN-induced loss of synaptophysin was also tested.