I have a question regarding proc.py gltsym. Below is the part of the proc.py script I am using which I intended to subtract brain activation during NF from F (F-NF).
If I’d like to do the subtraction on the other way around which is subtracting brain activation from F from NF (NF-F), can I simply change the gltsym into ‘SYM +NF -F’ and glt_label into NF_vsF?
Keep in mind that ‘SYM: NF -F’ will not give you any
more information. It is just the negative of the ‘F -NF’
contrast (betas and t-stats are negated).
If you have already run the full process, then
it is enough to use the existing results. Since
‘NF -F’ is the negative as ‘F -NF’, anywhere that
F_vs_NF is positive means F is greater, while the
negatives are where NF is greater. The NF_vs_F
contrast will just reverse that.
But if you wnat to run it, it is okay to put both
GLTs in the command (the second one gets label 2):
Thanks again for the comment. Can I have one more question? If I’d like to see the activation of only F, not subtraction, is it correct to run the script that looks like this?
-regress_stim_labels F \
-regress_basis ‘BLOCK(4,1)’ \
-regress_censor_motion 0.3 \
-regress_opts_3dD \
-gltsym ‘SYM: F’ \
-glt_label 1 F \
And, if I want to see the activation of NF, should I run the script below separately?
Thanks a lot for the quick response. Could you please check if I have checked correctly? If I am going to look at activation for a single stim file, I don’t need to specify the below in the proc py script?
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