Fig. 8.

Estimated correlograms from the real fMRI data, showing the asymptotic correlation, ρ_∞, in ρ_θ(h) (marginal correlation) is lower than the one in ${\rho }_{\theta }^{\ast }\left(h\right)$(h) (partial correlation). This might be related to the fact that a baseline condition of brain function exhibits decreases during performance of a cognitive task [41].