IGF1 and Alzheimer disease: Interestingly, the central impairment of glucose metabolism has been associated with insulin and IGF-1 resistance [40,132,133,137] and is mostly apparent in the frontal, parietotemporal, and cingulate cortices [134], indicating that insulin resistance affects the same regions as those affected by AD [54], and suggesting a link between central insulin resistance and this neurodegenerative disease.