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. 2008 Dec 23;30(9):2701–2721. doi: 10.1002/hbm.20704

Table  .

Parameter Interpretation Value
a e Efficacy of glucose consumption response to excitation 1
a i Efficacy of glucose consumption response to inhibition 1
τe Time‐constant of the excitatory glucose consumption impulse response. 1
τi Time‐constant of the inhibitory glucose consumption impulse response 0.8
c Steepness of the sigmoid function x 2.5
d Position of the threshold of the sigmoid function x 1.6
δe Delay between excitatory neuronal activity and corresponding glucose consumption. 0.1 s
δi Delay between inhibitory neuronal activity and corresponding glucose consumption. 0.1 s
δf Delay between excitatory neuronal activity and CBF response 0.2 s
γ Baseline ratio of excitatory to inhibitory synaptic activity in the voxel 5
ε Efficacy of blood flow response to excitation 0.6
τs Constant for CBF signal decay 1.5 (Friston et al., 2000)
τf Constant for CBF autoregulatory feedback 2.4 (Friston et al., 2000)
τ0 Transit time through the balloon 1 s (Buxton et al., 2004)
α Coefficient of the steady state flow‐volume relationship 0.4 (Buxton et al., 2004)
a1 Weight for deoxyhemoglobin change 3.4 (Buxton et al., 2004)
a2 Weight for blood volume change 1 (Buxton et al., 2004)
V0
Baseline blood volume 0.02 (Friston et al., 2000)