Rate of glucose oxidation in neurons as a function of the Glu/Gln cycle. The curves represent conditional averages, computed over solutions characterized respectively by Vcyc ≥ 0 and Vcyc > 0. The dashed lines identify the awake resting state (OGI = 5.5), corresponding to the group of solutions (Vcyc ≥ 0 and Vcyc > 0) plotted with the same color. For the condition Vcyc > 0, and possibly also for the condition Vcyc ≥ 0, the awake rest roughly corresponds to a change of the line slope. Thus, the transition from low to high activity is accompanied by a decreased energy consumption relative to what would be extrapolated at low activity levels. In particular, the slopes of the two curves at low Vcyc values are roughly 0.52 and 0.73 (for the groups Vcyc ≥ 0 and Vcyc > 0, respectively) and decrease to roughly 0.28 and 0.33 at high Vcyc values, suggesting a lack of energy demand at high activity (see text).