For the purpose of this work and future research, we define brain insulin resistance (BIR) as an inadequate response by cells located in the brain, including the cerebral vasculature, to secreted insulin: this inadequate response can be due to a limited CNS availability of insulin in its bioactive form, a limited expression of the insulin receptor (INSR) at the cell surface, a shift in INSR isoform expression, and/or diminished signaling events downstream from the INSR binding. Here, INSR is linked to Insulin resistance.