Hi, I have another couple questions for Gang (thank you so much for answering my previous question by the way!!!)
What is the best practice perform cluster correction when using 3dLME? I ran a model in 3dLME that cannot be done using the other programs, and got the residuals output using the -resid option. Should I get the ACF values from each subject’s first-level errts_REML, average those, and then feed those into 3dClustSim? Or is it okay if I just get the ACF values from the 3dLME residuals and use those for 3dClustSim?
I am analyzing a fMRI dataset of twins, and was hoping to account for twin-ness by doing a random intercept for each pair. My goal is to test the significance of the relationship between a contrast (cue_negative-cue_neutral) and a factor score (quant var). I was wondering - would it be ok to make my outcome variable the first-level contrast of interest? (i.e., cue_negative-cue_neutral#Coef)? This way, I have one row per twin, and two rows for each twin pair that share the same Subj code. Or should I model the task conditions separately (e.g., cue_negative and cue_neutral) as a within-subject variable? (so, feed it cue_negative#Coef and cue_netural#Coef for each subject)? I am confused as to what are the best practices here; I know other programs do the within- and between-subjects analyses separately, but looking at the 3dLME documentation examples it seems like it’s all done in one go here in AFNI’s 3dLME.
Thank you so much!!