Estimation of Directed Effective Connectivity from fMRI Functional Connectivity Hints at Asymmetries of Cortical Connectome
Fig 4
Need for tuning intrinsic noise Σ for each node in addition to C.
A Match between the recovered and the original C (red crosses) and Σ (purple triangles) for LO based on Eqs (15) and (20) with theoretical objectives and τest = 1 s. The original network has inhomogeneous noise Σii. B Comparison of Q error, C error and Pearson correlation coefficient for non-zero weights of the original C for four optimizations: ‘opt’ where both C and Σ are tuned as in A; ‘low’ for the tuning of C with a fixed Σ with the minimum value of the original Σ; likewise, ‘med’ and ‘high’ with a fixed Σ with the mean and maximum value of the original Σ. C Match between the original and recovered C for the optimization with fixed homogeneous Σ for three distinct values: the minimum, mean and maximum of the values in the original Σ. They are to be compared with the left panel in A.