Figure 4

Computed average rate of the glutamate-glutamine cycle versus average OGI. Simulations show that the average V_cyc increases as the average OGI decreases, consistently with the underlying relationship between OGI and glucose uptake. The curves represent conditional averages, computed over solutions characterized respectively by V_cyc ≥ 0, and V_cyc > 0. The red dashed line identifies the awake resting state (OGI = 5.5). The crossing points between the line at OGI = 5.5 and each of the two curves identify the values of V_cyc relevant for the basal conditions. Specifically, V_cyc is roughly 0.06 or 0.08 for the groups V_cyc ≥ 0 and V_cyc > 0, respectively. The two curves are significantly different for OGI $\gtrsim 4.75$. This is consistent with the fact that the contribution of solutions with V_cyc = 0 becomes negligible at high activation levels.