AFNI experts,

I am running proc py for functional data using stimulus files. In this dataset, there are two conditions (Condition A and Condition B), and three stimulus files (Stim I, Stim C, and Stim F). Firstly, I have compared Stim I and Stim C and the part of the proc py script was like below.

-regress_stim_labels I C \
-regress_basis 'BLOCK(1,1)' \
-regress_censor_motion 0.3 \
-regress_opts_3dD \
-gltsym 'SYM: +I -C' \
-glt_label 1 I_vs_C

After preprocessing, I ran 3dttest++ to compare between conditions (Condition A vs Condition B) using the belwo 3dttest++ script.

3dttest++ -prefix Flanker_Ex-Rest \
-paired \
-mask GM_mask_2009c+tlrc \
-clustsim \
-setA ConditionA \
subject1 stats.subject1.ConditionA+tlrc'[10]' \
.
.
subject 30 stats.subject30.ConditionA+tlrc'[10]' \
-setB ConditionB \
subject1 stats.subject1.ConditionB+tlrc'[10]' \
.
.
subject 30 stats.subject30.ConditionB+tlrc'[10]' \

It was processed successfully and I was able to examine the difference between conditions. Next, I wanted to compare Stim I and Stim F, so rerun the proc using the part of the script below.

-regress_stim_labels I F \
-regress_basis 'BLOCK(1,1)' \
-regress_censor_motion 0.3 \
-regress_opts_3dD \
-gltsym 'SYM: +I -F' \
-glt_label 1 I_vs_F \

When running 3dttest++ after preprocessing using the same script above, I had the below error message.

** ERROR: selector index 10 is out of range 0..9
** ERROR: bad sub-brick selector [10]
** FATAL ERROR: Option -setA: can't open dataset 'stats.subject1.ConditionA+tlrc[10]'

I changed sub-brick of each subject in 3dttest++ script like below
subject1 stats.subject1.ConditionA+tlrc'[9]' \
and it was running successfully, but the data look a little bit weird compared to using sub-brick 10.

Could you please let me know why the sub-brick error occurred even after using the same proc.py script and if using sub-brick 9 instead of 10 is correct?

Thank you in advance for your help,
Jun