Hello AFNI masters,

We have preformed a "standard" afni_proc.py pre-processing procedure and now want to deep dive a little by focusing only on the first 5 min out of a 7 min scan since we have some biometric data (blood samples) that only span over the first 5 minutes. We simply feed the pre-processed (wapred pb04.subjX.blur+tlrc) data into a new 3dDeconvolve command with our new special blood regressor.

My questions is this: We did not get identical results (potentially we could of course have done a mistake) when utilising two different "cutting" methods. One would be to tell 3dDeconvolve to stop at e.g. TR 300 (total TR count is 500) by using "-nlast 300" the other would be to fill the censor file with "0" from the 300th line.

Are these methods theoretically different? In the censor file case, perhaps the program still takes the rest of the time points into account for the regression without using them?

Also, I guess we could have screwed up since -nlast uses 0 as the first element and the censor file starts at line 1. -nlast 300 would mean to include 0-300(?). I.e. we should start filling with zeroes in the censor file at line 301.

So, -nlast vs -censor? Should be identical?

Thanks!



Edited 1 time(s). Last edit at 01/29/2018 06:57AM by Robin.