The Smoothing Artifact of Spatially Constrained Canonical Correlation Analysis in Functional MRI

Figure 4

Density estimation of active and inactive voxels in motor activation data. The top curve (dark blue) shows the distribution of the cnr using kernel density estimation techniques. The green and red curves are the estimated distributions of the cnr for the inactive and active voxels, respectively. Note that the distribution of the inactive voxels (green curve) was derived from wavelet resampled resting-state data using a dilation variable, whereas the distribution of the active voxels (red curve) was derived from a Gaussian distribution. The mixture of the estimated distributions for null and active voxels is given by the light blue curve showing very small differences to the raw curve (dark blue).