Surface-related
*(Eccentricity tuning). Here we continuously get more and more aggressive in the filtering/thresholding (omitting voxels according to some variance explained metric). We do the sweep in order to get a full birds-eye view of the nature of the data. Consider varying the threshold a little to get a sense of making sure that your assessment of the dataset is accurate (despite any specific arbitrary threshold level).
Same data, one on the native subject surface and then transferred to the fsaverage surface. There are large-scale distortions that occur due to forcing things onto "group template"; There are also intrinsic spatial distortions due to the fact that we are viewing things on a "flat surface".
Same data ("atlas labeling") on two different surfaces, just to give an example of how to "visually interpret" such different views of the same data.
Chopped off end of the brain, comparing an "inner" cortical surface vs. an "outer" cortical surface.
Triangulated mesh (representing a cortical surface). Triangles, edges, nodes/vertices. Variations in mesh density. Maybe what's going on is deliberately reducing vertex density when the surface is relatively flat.
A shaded triangulated mesh.
*Individual subjects' curvature and then the average across subjects. This assesses curvature based alignment approaches.
Another example of checking curvature-based alignment
This movie shows intuitively what inflation is really doing to your anatomy. Notice that on the first frame, there are a few segmentation errors / surface artifacts / geometrical errors.
Visual example of surface smoothing.
*Check cortical surface reconstruction quality
T1 left, curvature middle, sulc right. Curvature is correlated with, but distinct from sulc (how far you are from the convex hull of the hemispheres.)
Voronoi shading of a triangulated mesh.
Left: "standard" Freesurfer flattening based on the white surface. Right: a "hacked-FreeSurfer" flattening based on the pial surface. It's the same brain, but very different geometric characteristics. Notice there is a problem in the right hand one (near the mid-left), so maybe not great for actual use.