1. Human ex vivo model: (1) brain autopsy of patients with HIV/AIDS. (2) HIV-1 infection in primary human neurons and microglia, treated with insulin. Outcome measures: neuroinflammation and neuronal death. 2. Animal in vivo HAND model: feline retrovirus (FIV) intracranial infection in cats. Insulin intranasal treatment for 6 weeks compared to PBS treatment. Outcome measures: morphological changes in the brain, neuroinflammation, neuronal survival, neurobehavioral performance. The gene discussed is INS; the disease is HIV-1 infection.