APP and Alzheimer disease: However, although Aβ-oligomers significantly impaired synaptic function in the present APP knock-in mouse model at 5 months of age, as reflected in the decrease in structural plasticity of dendritic spines, we saw no loss of post-synapses, as it was shown in later stages of AD (Ferrer and Gullotta, 1990; Moolman et al., 2004; Spires et al., 2005; Koffie et al., 2009).