Hi, freesurfer communityI'm Francisco Robles, from the Instituto Nacional de Neurología y Neurocirugía in México city. I am using FS-Fast to analyze some event-related fMRI. My problem is how to use the paradigm file because I need to exclude some images from my analysis. The situation is that I have a paradigm of 3.5 secs of stimulus and a variable quantity of Null/fixation. But from those 3.5 secs of stimulus, I only want to analyze the last 1.75 secs. The opseqt file I've got goes like this:

0.0000 2 3.500 1.0000 var1 3.5000 4 3.500 1.0000 var3 7.0000 4 3.500 1.0000 var3 10.5000 3 3.500 1.0000 var2 14.0000 0 1.750 1.0000 NULL And I edited it to look like this but I really don't know if it is the right way to do it:1.75 2 1.75 1 "var1" 5.25 4 1.75 1 "var3" 8.75 4 1.75 1 "var3" 12.25 3 1.75 1 "var2" 14.00 0 1.75 1 "NULL" So I put in the column of stimulus onset, the time point I want to analyze and in the duration column, only the quantity of time I want to analyze. But I've seen in mkanalysis-sess.new on wiki, that there is a flag -tpef [filename] for the command selxavg3-sess that allows to exclude certain files according to a time-point, but I don't know how to do it, how is the arrange of taht file, how many columns, how do I say to it that I only want the last 1.75 secs and not the hole 3.5 secs. I am really lost, if anyone can help mw I will appreciate it a lot. Thank you all in advance.

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