INS and Alzheimer disease: It was previously reported that insulin signaling is compromised in the post mortem brain samples of Alzheimer’s disease patients (Steen et al. 2005; Freude et al. 2009; Morgen and Frolich 2015) and intranasal insulin administration (Freiherr et al. 2013; Chapman et al. 2018), as well as some other drugs like the insulin sensitizer metformin (Koenig et al. 2017; Markowicz-Piasecka et al. 2017) were shown to improve the cognitive performance.