The impairment of insulin signaling in Alzheimer's disease.

Alterations of the insulin signaling cascade underlie cognitive decline and the development of several neurodegenerative diseases. In recent years, a great interest has been put in studying the interaction between diabetes and Alzheimer's disease (AD). In fact, evidence shows that both diseases present several biochemical similarities including defects in the insulin signaling pathway. Here, we give an overview of the main functions of insulin in the central nervous system. The impact of insulin signaling impairment in brain aging and AD is also discussed. Finally, we present evidence supporting the notion that insulin is a link between diabetes and AD.