Hi Justin,
1. Was your dilation applied in 3dAutomask? If so, it is
not a simple dilation. Please describe more specifically
what you are doing, including commands.
2. I gather you mean the data has been masked and blurred
using a Gaussian kernel (3dmerge). If so, the data at the
edges are blurred, too. That means brain data values are
blurred outside just as outside values are blurred inside.
Moving the border farther out means less of the outside
signal is included at a given edge voxel, say.
If you want to restrict the blur to your mask, consider
using 3dBlurInMask.
- rick
