Intranasal insulin delivery, which bypasses peripheral circulation and delivers insulin directly to the brain, has been shown in multiple preclinical AD models (including intracerebrovascular streptozotocin rats) to improve cognitive function, reduce tau hyperphosphorylation, decrease neuroinflammation, and promote hippocampal neurogenesis without affecting peripheral glucose or insulin levels [52]. The gene discussed is INS; the disease is Alzheimer disease.