Fig. 1

Indices of the accuracy of spherical spline interpolation across various conditions. Top panel: similarity index of temporal Pearson correlations between original and interpolated signals, which were averaged across all electrodes. Bottom panel: dissimilarity index of root of mean square error (RMSE) computed using the differences between original and interpolated signals, which were averaged across all electrodes. Both the similarity and dissimilarity indices strongly varied across the levels of number of electrodes, m, n, and λ parameters. All of the between-level differences were statistically significant in paired t-tests (p < .001), even between the n = 20 and n = 50 that look nearly identical due to very little variability in the difference values