Hi again,

The -1thresh option is for using a statistical sub-brik to censor a coefficient sub-brik. It looks like you have a single sub-brik dataset, so this option may not work as expected if your input dataset, the output of your 3dcalc command, is a single sub-brik.

What are the dimensions of a single voxel in these data? It looks like you expect "contiguous" voxels to be within 5.7 mm of one another. Is this the distance from center to center of voxels that are in-plane as well as between slices? 105 should be the number of microliters that 3-4 voxels fill up, based on their dimensions.

You can check if the cluster on the unclipped data is contiguous by placing the cross-hair over a voxel and stepping through consecutive slices. The cross-hair should appear over the presumed contiguous voxels when you move into the new slice.

good luck,

-j