MAPT and Alzheimer disease: About the crucial question regarding the two potentially “dangerous” proteins to which the responsibility of giving first the green light to the disease is attributed, in light of the recent data [76,77,78] it is clear that Aβ and tau pathologies exert cooperative and/or synergistic deleterious effects on neuronal function(s) (“dual hit” hypothesis), particularly at synapses which are believed to initiate the AD progression.