Dear Freesurfer experts,

I am doing a longitudinal repeated measures ANOVA 2x2, with two groups (experimental vs control) and two time points (pre and post treatment).

I have followed the group analysis tutorial ( MailScanner has detected a possible fraud attempt from "secure-web.cisco.com" claiming to be https://surfer.nmr.mgh.harvard.edu/fswiki/FsTutorial/GroupAnalysis#GLMAnalysis.28mriglmfit.29 ), where it is suggested to do a Z Monte Carlo simulation with the following command:

mri_glmfit-sim \ --glmdir lh.gender_age.glmdir \ --cache 4 neg \ --cwp 0.05\ --2spaces

However, I have two questions regarding this issue:

1) I would like to know whether is it correct to use for example --cache 3 or 2 instead of 4. Is it recommended?

2) Is it better to use, instead of the above Z Monte Carlo simulation command, a permutation with the following command?: mri_glmfit-sim \ --glmdir lh.gender_age.glmdir \ --perm 1000 4.0 abs \ --cwp 0.05\ --2spaces \ --bg 1

Is it appropriate to use any of both? I do not know which is more recommended or whether both are adequate so I can simply choose, for example, the first one.

Thank you very much in advance.

Kind regards,

Agurne

Neuropsychology of Severe Medical Conditions Research Team

Dpt of Methods and Experimental Psychology
Faculty of Psychology and Education

University of Deusto

neurolab.deusto.es

Avda. de las Universidades 24,

48007, Bilbao (Spain)

Phone: +34 944139000 (ext. 3015)