I used 3dmerge to cluster order some T-maps and came up with 1 or 2 giant clusters that span from the inferior frontal cortex back past the posterior commissure (~11,000 microliters). I have used the -1erode command, with little success. I then extracted these large clusters individually and multiplied each cluster by the Talairach atlas to break it up using: 3dcalc -a input+tlrc -b TTatlas.big+tlrc -expr 'rect(a-1)*b' -prefix giant.blob

I'm not sure where to go next. If giant.blob+tlrc now has 12 clusters (based on the Talairach atlas), should I individually extract them and then add it to a final combined mask? Do I need to run these new clusters through 3dmerge again to make sure they still pass the statistical thresholding and minimum cluster volume criteria?

Finally, after I multiply the extracted cluster by the Talairach atlas, I don't know exactly how many clusters are present. Because I've multiplied by the Talairach atlas it is not a simple task to match the Talairach value to a specific color on the intensity scale. Is there any way to count the new clusters without having to do it manually? (when I run 3dclust I still come up with some giant clusters).

Thanks in advance for the help.