Fig. 2.

Time series of ¹³C-MR spectra, acquired from a ~125 mL voxel, placed in the occipital cortex. Spectra are averaged over 20 min, after administration of [1-¹³C]glucose during a hypoglycemic clamp in one healthy subject. Once the infused [1-¹³C]glucose is taken up by the brain and incorporated into various glucose metabolites, an increase in signal over time is observed. Numbers indicate the position of the ¹³C label, as explained in more detail in Fig. 3. Asp aspartate, Gln glutamine, Glu glutamate, Lac lactate (from Ref. [143], with permission from Elsevier)