Table 2.
Sensitivity analysis for key parameters in each section of the calculations
| Parameter increased by 10% | Percentage change | To result for | |
|---|---|---|---|
| Energy budget for the white matter | P12 | Adult | |
| Voltage change for action potential | 10.0 | 10.0 | Total ATP use on APs (ATP/m3/s) |
| Internode length | −0.01 | −0.31 | Total ATP use on APs (ATP/m3/s) |
| Node length | 0.01 | 0.34 | Total ATP use on APs (ATP/m3/s) |
| g ratio | 1.80 | 73.4 | Total ATP use on APs (ATP/m3/s) |
| Action potential Na+ entry scaling factor | 10.0 | 10.0 | Total ATP use on APs (ATP/m3/s) |
| Mean firing rate | 10.0 | 10.0 | Total ATP use on APs (ATP/m3/s) |
| Mean firing rate | 10.0 | 10.0 | Total ATP use on synapses (ATP/m3/s) |
| No. OPCs in P12 rat optic nerve | 10.0 | 10.0 | Total ATP use on synapses (ATP/m3/s) |
| No. synapses/OPC (and hence charge entry) | 10.0 | 10.0 | Total ATP use on synapses (ATP/m3/s) |
| Vesicle release probability (and hence charge entry) | 10.0 | 10.0 | Total ATP use on synapses (ATP/m3/s) |
| Resistance per area of axon under myelin | −0.5 | −0.8 | Total ATP use on RPs (ATP/m3/s) |
| Oligodendrocyte resting potential | −17.1 | −17.1 | ATP on oligodendrocyte RP |
| ATP use on nonsignaling processes | 6.20 | 5.55 | Total white matter/grey matter ATP use |
| Energetic costs and benefits of myelination | |||
| Mean firing rate | −9.09 | Days to pay back myelin assembly cost | |
| Oligodendrocyte resting potential | −17.1 | Energy saving firing rate | |
| Oligodendrocyte input resistance | −9.1 | Energy saving firing rate | |
| Energy supply and production in myelinated axons | |||
| O2 use by muscle mitochondria | 10.0 | GLUT3 density at node (GLUT3/μm2) | |
| Turnover rate of GLUT3 | −9.1 | GLUT3 density at node (GLUT3/μm2) | |
AP, Action potential; RP, resting potential.