INS and type 2 diabetes mellitus: It has been reported that cerebral insulin resistance in type 2 diabetes is associated with an altered neural response to insulin and disorders of food cravings and hunger, which may induce cognitive dysfunction by affecting dopamine signaling (Kleinridders et al., 2015), impairing the blood-brain barrier (Rhea and Banks, 2019), and damaging hippocampal synaptic plasticity (Biessels and Reagan, 2015).