Just to clarify and reiterate Paul's explanation, a=dset1, b=dset2, the conjunction is set up in that formula to be 3. More specifically, these are the masks for dset1 and dset2 (affective, informative). If you set b=dset2 (say "informative" in your example), you could use just 1*b, but that would give you only a value of 1, and that's the same as as if dset1 is true at at that voxel, so you can't tell the difference between 1 from affective and 1 from informative. By multiplying dset2*2, you can tell a difference because the informative mask gets a value of 2. The combination (conjunction) gets the sum of 3. The help for 3dcalc has a similar example, and there's also another similar example in the afni11_ROI.pdf from the class handouts.

For the coloring, you could write and read in a palette file, but that may be a little trickier than what you want or need. First take a look at the paned colorbars, where the "**" appears below the color bar. Each of the colors in the color bar there is selectable to change the color or to move the range. Select one with 3 colors. Another way is to use one of the ROI color bars and set the range to the number of colors in that color bar, ROI_32 -> range=32. You can make this happen automatically when you view the file with "3drefit -cmap INT_CMAP my_conjunctionmask_dset".



Edited 1 time(s). Last edit at 07/17/2017 11:20AM by Daniel Glen.