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Hi Freesurfer experts,
I'm trying to constrain my sMRI analysis to only search for brain regions
(GMV) that are correlated with a behavioral measure within a mask (made
from a functional contrast of interest, so that I'm only searching for
regions that were shown to be active during a language localizer task)
using mri_glmfit. I've followed recommended steps to transforming my fMRI
contrast into a surface mask, and then later even tried making it into a
surface label, however whenever I run the analysis, I get the same results
regardless of whether I use the --mask or --label option, meaning that the
summary file (cache.th40.pos.sig.cluster.summary) includes regions that are
outside the mask. How can I ensure that mri_glmfit actually uses the
mask? I've included below the commands I have run.
I previously ran mri_glmfit to search the whole brain for regions
significantly correlated with behavioral measures using the following
command:
mri_glmfit --y fsgd_VSL_std_age_gender_TIV.volume.00B.mgh --fsgd
fsgd_VSL_std_age_gender_TIV.txt --C Contrast_VSL_std_a_g_TIV.txt --surf
fsaverage lh --cortex --glmdir lh.VSL_std_age_gender_TIV.glmdir
Now, when I try to use the mask, I get the same results as above
(significant result in regions outside of mask), using the following
command:
mri_glmfit --y fsgd_VSL_std_age_gender_TIV.volume.00B.mgh --mask
localizer_mask.mgh --fsgd fsgd_VSL_std_age_gender_TIV.txt --C
Contrast_VSL_std_a_g_TIV.txt --surf fsaverage lh --cortex --glmdir
lh.VSL_std_age_gender_TIV_localizer_mask.glmdir
I also converted the mask into a label just in case, and used the following
command:
mri_glmfit --y fsgd_VSL_std_age_gender_TIV.volume.00B.mgh --label
<path>/freesurfer/fsaverage/label/LeftMidAntTemp_surf.label --fsgd
fsgd_VSL_std_age_gender_TIV.txt --C Contrast_VSL_std_a_g_TIV.txt --surf
fsaverage lh --cortex --glmdir
lh.VSL_std_age_gender_TIV_localizer_label.glmdir
Across all these conditions, I always get the same results (even if the
significant region is outside of the mask). Are there any recommendations
for steps I should take to make sure I'm only searching for regions inside
the mask?
Best,
Jen
--
Jennifer Legault
PhD, Neuroscience
Postdoctoral Scholar
Language Acquisition and Brain Lab
University of Delaware