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Hi,
Which specific file should I load? I see cluster.mgh, cluster.summary,
sign.ocn.annot, sig.ocn.mgh, sig.vertex.mgh, and pdf.dat.
How can I extract the values from fsaverage space?
Basically, what is the correct way to extract values from these significant
clusters?
Many thanks,
Omar
Date: Tue, 3 Sep 2019 15:15:02 +0000
From: "Greve, Douglas N.,Ph.D." <dgr...@mgh.harvard.edu>
Subject: Re: [Freesurfer] qdec contrast and data extraction
To: "freesurfer@nmr.mgh.harvard.edu" <freesurfer@nmr.mgh.harvard.edu>
Message-ID: <2286f9bf-37a4-1be9-2252-0bccc833a...@mgh.harvard.edu>
Content-Type: text/plain; charset="utf-8"
You might have done something wrong along the way. When you run the
montecarlo correction, it will create a file with the thickness values in it
for each cluster. the first thing to do is to load that and see if you see the
expected differences. The other thing is to not go back into native space to
extract the numbers. There are several operations that happen as it moves into
fsaverage space and in preparation for group analysis (interpolation, and
smoothing); sometimes these make a big difference. if the ROI is small, it may
not map accurately back into the native space (and you should not need to draw
it in the first place)
On 8/30/2019 11:36 AM, Maximo, Jose Omar wrote:
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Hi,
I have a question:
My design is 2 groups (HC and Patients in that respective order) and 2
nuisance factors (age and eTIV). When I look at the average volume difference
between the 2 groups, I get blue and red clusters. I presume the color coding
is where each group is greater than the other (Blue = Patients > HC and Red =
HC > Patients).
Then, I processed to extract individual values from each cluster in order
to plot them. When I extract data from the blue clusters and plot them, the two
groups show no difference in thickness at all, whereas when I look at volume,
HC show more than patients in blue clusters (see attached figure). I would
assume that both figures would show patients > HC based on the negative
statistic.
Am I interpreting the colors wrong? Or am I doing something wrong?
These are my steps 1) After applying montecarlo correction, I drew my ROIs
to extract the data from; 2) map it onto every single subject; and then 3) used
mris_anatomical_stats to extract the data from each subject.
Any suggestions are welcome.
Best,
Omar
Jose O. Maximo, Ph.D. | Postdoctoral Fellow
Department of Psychiatry & Behavioral Neurobiology
UAB School of Medicine
University of Alabama at Birmingham
Cell Phone: (619) 252-3492
Email: jomax...@uabmc.edu<mailto:jomax...@uabmc.edu>
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