Hi Mark,
> 1) Is it possible that 1 faulty subject with artifact could
> apply this artifact to all other subjects during tbss_2_reg
> and tbss_3_postreg?
Hmmm, the only way it could (well that I can think of) is if you were unlucky enough for your "best target" to be this "faulty" subject.
It must have been the case since the subjects didn't show the artifact after you've removed this subject and re-ran tbss3 (if you want to be sure, after running tbss3, the name of the best target is in best.msf, so this should change after removing the outlier)
> 2) Is it possible to remove a subject (and all associated
> files) from a TBSS analysis after tbss_2_reg has already
> ran?
I don't think this would be a problem.
> 3) Could the troubleshooting attempt in #2 affect the
> statistical analysis and power to detect direct
> between-group differences?
Unfortunately, I don't think so. Do your t-map/uncorrected p-map seem sensible?
Hope this helps,
Gwenaelle
