INS and Alzheimer disease: The very fact that INI appears to be an effective approach to elevate central IR signaling and alter mood, appetite, and cognition across the aging spectrum, as well as in individuals with significant amyloid pathology and/or AD and MCI-associated cognitive impairment, suggests that the traditional premise of central insulin resistance as defined by the inability of the IR to respond to the ligand may not be as prevalent as previously thought.