Hi,
I'm resending this e-mail, as it didn't seem to go through correctly yesterday:
I’m a Freesurfer novice, and I’m confused about how to run a 3rd level cross-subject analysis on the surface using as input cross-run .gfeats from 10 subjects generated from a 2nd level analysis in FSL.
Following the directions posted at http://surfer.nmr.mgh.harvard.edu/fswiki/FsTutorial/FslGroupFeat, I have sampled the .gfeat copes and varcopes into standard surface space, using mris_preproc.
I would then go on to perform a 3rd level surface based analysis as the instructions suggest, using:
mri_glmfit --y xrun/lh.cope1.mgh --yffxvar xrun/lh.varcope1.mgh --ffxdof 163 --osgm --glmdir xrun/lh.osgm.ffx --surf fsaverage lh --label $SUBJECTS_DIR/fsaverage/label/lh.cortex.label
However, I want to use a random as opposed to fixed effects analysis. How do I do this? I tried --yrfxvar as opposed to --yffxvar but it didn’t work. And if I’m going to display the map resulting from this analysis, do I need to correct for multiple comparisons?
Many thanks in advance,
Susan McLaughlin Doctoral Candidate SPACE Lab (Stimulus-Parametric Imaging of Auditory Cortex) Dept. of Speech and Hearing Sciences University of Washington