INS and Insulin resistance: A number of studies have demonstrated that brain insulin resistance associated with a reduction in insulin and insulin-like growth factor 1 (IGF-1), inactivation of the insulin receptor substrate 1/2 (IRS 1/2), Akt and mTOR and GSK-3β phosphorylation (Hölscher, 2020; Schubert et al., 2004; Sedzikowska and Szablewski, 2021).