INS and Alzheimer disease: These investigations demonstrated a significant increase in neuronal apoptosis and a significant decrease in downstream Akt and GSK3β phosphorylation levels, insulin resistance, and AD-related anxiety and depression (Brüning et al., 2000; Schubert et al., 2004; Kleinridders et al., 2015), thus indicating a potential link with high insulin levels in the synapses and its essential role (Werther et al., 1989; Abbott et al., 1999; Bockmann et al., 2002).