- Unchanged basal levels of insulin and IGF-1 signaling molecules- Trend to increase IRS-1 levels in hippocampus- ↓ in responses to insulin signaling in the IR→IRS-1→PI3K signaling pathway and greater→ in responses to IGF-1 in the IGF-1R→IRS-2→PI3K signaling pathway in AD- IRS-1 pS616 and IRS-1 pS636/639 correlated positively with Aβ plaques and negatively associated with memory. Here, INS is linked to Alzheimer disease.