The only big difference is the one you are running into, and that's that optseq2 optimizes each run separately instead of concatenating the runs together. You'll have to divide your 4 presentations among 6 runs, which will create a bit of a mess because some runs won't have any of a certain condition. You might want to stick with the old optseq.

doug

Dan Dillon wrote:

Dear FreeSurfers,

I’m having a little trouble getting something that works in optseq to work in optseq2. Here’s what’ is going on . . . when I run this command, things work fine and I get 6 nice sequences:

optseq -ntp 170 -TR 3 -npercond 4 4 4 4 4 4 -tpercond 17 17 17 17 17 17 -label NgReal NgLook NgPhoto NuReal NuLook NuPhoto -nsessions 6 -nruns 1 -timewindow 20 -prestim 4 -nsearch 50 -o OptseqTEST

However, when I run this command (i.e., my best translation of the previous command into optseq2), I get an error saying that all my schedules are ill-conditioned and I need more scan time or fewer repetitions:

optseq2 --ntp 170 --tr 3 --psdwin 0 20 1 --ev NgReal 17 4 --ev NgLook 17 4 --ev NgPhoto 17 4 --ev NuReal 17 4 --ev NuLook 17 4 --ev NuPhoto 17 4 --nsearch 100 --nkeep 6 --o Optseq2TEST

Is this a substantive difference between optseq and optseq2 or did I make a mistake with my optseq2 command? Also, I’m assuming there is a reason why I should use optseq2 rather than optseq, but I don’t know what it is. Can someone clue me in?

Thanks!

Dan Dillon, Ph.D.

Post-doctoral Fellow

Affective Neuroscience Lab

Dept. of Psychology, Harvard University

Phone: (617) 495-1889

E-mail: dillon@wjh.harvard.edu mailto:dillon@wjh.harvard.edu

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