Table III.
Description of parameters in Model
| Symbol | Description | Physiological range | Citation | |
|---|---|---|---|---|
| Arterial resistance temporal basis | ΔRAlmax | Maximum change arterial resistance | [0–90] [−90–0]% | — |
| τonset | Time to onset of resistance change | [0–6]s [0–6]as | — | |
| σA | Width of temporal resistance change | [0–8]s [0–8]s | — | |
| CMRO2 temporal basis | ΔCMRO2Max | Maximum change in relative CMRO2 | [0–50]% | — |
| τonset | Time to onset of CMRO2 change | [0–4]s | — | |
| σM | Width of temporal CMRO2 change | [0–8]s | — | |
| Vascular model parameters | RA(0) | Initial arterial resistance | [20–90]% | (Boas et al., 2003) |
| β | Windkessel vascular reserve | [1.1–5] | (Mandeville et al., 1998b) | |
| τ | Vascular transit time | [0.5–4]s | (Ito et al., 2005) | |
| τpial | Pial venous transit time | [0–4]s | — | |
| Oxygen saturation | SaO2 | Baseline arterial saturation | [95–100]% | |
| ScO2 | Baseline capillary saturation | [60–90]%b | (Herman et al., 2006) | |
| SvO2 | Baseline venous saturation | [55–89]%b | ||
| NIRS lead field | [HbT]0 | Total baseline blood volume | [40–140]μM | (Tomcelli et al., 2001) |
| ωpial | Pial vascular sensitivity | [0–1] | — | |
| BOLD lead field | Vo | Baseline vascular volume fraction | [1–10]% | (Ito et al., 2005) |
| ε | Intrinsic ratio of intra/extra‐vascular signal | [1–5] | — |
This table shows the parameters used in the model described in the text. Physiological ranges are used to set the upper and lower bounds for each parameter used in the fitting procedure as determined from the provided citations. The baseline oxygen saturation of each vascular compartment was estimated in the full multimodal model only.
a
Onset time for the arterial contraction response is defined as the lag time after the onset of the dilation response.
b
Capillary and venous oxygen saturations are defined by the change from the previous compartment to ensure that SaO2 > ScO2 > SvO2.