In the Holy Script, a paradigm file is used to subdivide a bunch of image volumes into groups. E.g., you might have with 84 scans in the IR paradigm, but some belong to the Fix group, some belong to the RealWord group, and some belong to the FalseFont group. The IR1.pdgm and IR2.pdgm files indicate which scans belong to which group. Mean-diff images and T-test contrasts are then performed between the groups defined by the paradigm file. By convention, paradigm files are named with a .pdgm extension.

To create a paradigm file, the first thing you must do is to write down somewhere exactly what conditions were happening during each scan. I'd suggest doing this in an Excel spreadsheet. In column A, for the i-th row, type in the condition that was happening during the i-th scan. So, for example, if the subject was doing the Fix (fixation) condition during the 10th scan, then type in "Fix" into cell A10. Do this for all scans; so if your study had 84 scans, you should fill in cells A1 through A84.

Then you must create a new Paradigm file; give it a descriptive name like Bilingual.pdgm or Typing.pdgm. Here is the Paradigm file for the IR1 task as an example. You can see that under "# groups" it has listed the three conditions, Fix, RealWord, and FalseFont, as well as a third group All which simply signifies all conditions. Under "# group colors", it indicates desired colorations for each group (this is arbitrary, and actually doesn't come into play in our analysis so just keep defaults). Under "# time points", it lists blocks of scans in the 1st column, and in the 2nd column it lists the conditions that were happening in that block -- this is where you transfer info from your Excel spreadsheet into the new Paradigm file. To tell you the truth, I am not sure how "# contrasts" was intended to be used in practice.

One way you can create this new Paradigm file is by hand, using a text editor such as gedit under Linux; just edit a copy of the IR1 paradigm and modify it to fit your new paradigm. Or, you can make it in MEDx, by selecting Toolbox --> Functional --> Define Paradigm..., and following the directions on pages 31-2 through 31-5 of Chapter 31 of the MEDx User's Guide (just leave the Contrast Fields blank). I'd suggest doing it in MEDx. See also steps 8 through 12 in this MEDx tutorial.

If you get an error message like

you probably haven't defined a group named EIRRealWord in your paradigm file. To solve this problem, you can either

(1) Modify the paradigm file so that it does define a group named EIRRealWord; or

(2) Modify your protocol .txt file so that its Contrasts refer to groups that you're actually defining in your paradigm file.