Figure 2.

Illustration of the high-resolution protocols used in this study. a, Illustration of the slice orientation and location. The slice orientation was tilted to reduce distortion. (Note that this illustration contains only 16 slices instead of 27, which would be too fine for the resolution of this print.) b, Superposition of functional and anatomical data. Anatomical data are in gray scale, functional data in red–yellow. There is substantial structural information in the functional data. This structural information was used for careful alignment. Note that the T2*-weighted EPI scans and the T1-weighted scans have inverted contrast properties. c, As for b but with the red EPI image thresholded for brightness, i.e., voxels below a threshold luminance in the EPI scan are made transparent and accordingly replaced by the T1 image (gray). This view is particularly useful to check the precision of the spatial alignment between the anatomical (T1) and functional (EPI) scans and further to detect any distortion. Ideally, the remaining red–yellow image should fill the dark sulci of the anatomy.