INS and Alzheimer disease: This is a comprehensive study aimed at establishing the effects of dietary lipoic acid on brain function in a triple transgenic mouse model of Alzheimer’s disease and addresses effects on substrate supply assessed by brain glucose uptake ([18F]-FDG-PET imaging) and glucose transporters translocation to the plasma membrane, the modulation of glucose metabolism by the PI3K/Akt pathway of insulin signaling, mitochondrial oxidative metabolism capacity, and synaptic plasticity.