Figure 5

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 V_cyc ≥ 0 and V_cyc > 0. The dashed lines identify the awake resting state (OGI = 5.5), corresponding to the group of solutions (V_cyc ≥ 0 and V_cyc > 0) plotted with the same color. For the condition V_cyc > 0, and possibly also for the condition V_cyc ≥ 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 V_cyc values are roughly 0.52 and 0.73 (for the groups V_cyc ≥ 0 and V_cyc > 0, respectively) and decrease to roughly 0.28 and 0.33 at high V_cyc values, suggesting a lack of energy demand at high activity (see text).