A revised coupling between synaptic activity and glucose metabolism. Glucose uptake (green) is now ubiquitous. Astrocytic lactate flow (orange) to neurons is now less, with a small amount being effluxed to blood. ATP is produced oxidatively (orange) in neurons and astrocytes. ATP produced by glycolysis (yellow) fuels ion pumping and glutamine synthesis in astrocytes. Abbreviations: Glu, glutamate; Gln, glutamine; Pyr, pyruvate; Lac, lactate in astrocytes. See Hyder et al (2006) for details. Modified from Hyder et al (2006), Journal of Cerebral Blood Flow and Metabolism, NPG.