Figure 3.

Examples of recovered hemodynamic response functions. (A) Is a case where the initial (“no correction”) HRF is very poor and PCA, spline, and wavelet approaches can be seen to improve it. (B) Is a case where the initial HRF is reasonably accurate but likely contaminated by motion. Here the HRF is improved by trial rejection and all four motion correction techniques. (C) Shows a case where the initial HRF is very accurate. Trial rejection is detrimental to the HRF as are PCA, spline, and wavelet corrections.