gPPI Interaction Regressor Question

Hello! I am working on my first gPPI analysis and have a question regarding this portion of the AFNI gPPI script as shown on this page:

For obtaining the interaction regressors, this is what is first suggested:
'First create a 1D (one column) file, conditionA.1D, with 0’s (at those TR’s where condition A does not occur), 1’s (at those TR’s where condition A occurs). Unlike the traditional PPI, no contrasting is performed here (thus no -1’s)."

To create this file, would something like be sufficient? And then, would this file serve as the input, “one1.1D”, as stated in this section of the sample script: “head -${cc} stimuli/Allruns_stim_${cond}_time.1D |tail -1 > tmp.1D
waver -dt ${sub_TR} -FILE ${sub_TR} one1.1D -tstim cat tmp.1D -numout ${n_tp} > ${cond}${cc}${sd}.1D”
Any advice is greatly appreciated.

Thank you,

Hi Ian,

Sorry for being slow. Maybe you are working with Prerona. Hopefully this will be useful:

  • rick