INS and infection: Intranasal insulin administration in a mouse model of HIV-NCI (EcoHIV-infected mice) produced cerebrospinal fluid insulin levels similar to those seen in patients and, when initiated 23 days or 3 months post-infection, it fully reversed neurocognitive impairment along with associated neuronal and gene expression deficits, the reduction in hippocampal dendritic arborizations, and restored cognitive acuity.