Hello,
Just reposting a message not answered yet.
Many thanks!
Pablo


From: pablonajt@hotmail.com
To: freesurfer@nmr.mgh.harvard.edu
Date: Tue, 6 Oct 2015 14:39:13 +0000
Subject: Re: [Freesurfer] percent difference adjust to results {Disarmed}

Hello Doug,
Group.mean.mgh doesn't look negative see when opening with tksurfer, below.
  
 
 


I re-run the computation to make sure. When I opened the pctdiff and increased the minimum threshold from 3 to 4 and above the colour maps changed from light blue to yellow. 
Pctdiff with threshold 3
  
 

 

With threshold 4
 


 
 

Could you advice which would be the right setup and also how do I figure it out how much percent difference in the cluster of my results below, please?

  

 
 













Date: Mon, 5 Oct 2015 19:28:06 -0400
From: greve@nmr.mgh.harvard.edu
To: freesurfer@nmr.mgh.harvard.edu
Subject: Re: [Freesurfer] percent difference adjust to results {Disarmed}

It looks like the pctdiff changed sign which would happen if group.mean.mgh had negatives. Does it?

On 10/3/15 2:38 AM, pablo najt wrote:
Hi my message was lost in the long correspondences. Would anyone advice about below, please?
Thank you.
Pablo


From: pablonajt@hotmail.com
To: freesurfer@nmr.mgh.harvard.edu
Date: Thu, 1 Oct 2015 11:47:10 +0000
Subject: [Freesurfer] percent difference adjust to results {Disarmed}

Dear FS experts
I have a query about how can I make that the percent difference results matches the same clusters of my output from my main glm analysis.
I run a glm analysis g4v1 (Male_Pt, Male_HC, Fem_Pt, Fem_HC) with Age and sex as covariates.
My contrasts are as follow 
-0.5 0.5 -0.5 0.5 0 0 0 0
This contrast is meant to test "is there a difference between HC and PT controlling for age and sex.

I separately run contrast of PT agains "0" 
0.5 0 0.5 0 0 0 0 0
and HC against "0"
0 0.5 0 0.5 0 0 0 0

calculated percent difference as follows 
fscalc Pt_group/gamma.mgh add HCgroup/gamma.mgh div 2 -o group.mean.mgh 
Then computed the percent difference: fscalc HCgroup/gamma.mgh sub Pt_group/gamma.mgh div group.mean.mgh mul 100 -o pctdiff.mgh

Now when I open my results from the first contrast above and the pctdiff.mgh separately, I am not quite sure they match. How could I adjust the min and saturation values to make them match and show how much percent difference is between the groups in the cluster shown in the main contrast. I have embedded the two results and parameters to give you an idea of how I am setting this up and if there is anything I can tune to improve visualisation.
Thank you very much in advance.
Pablo 

results from main contrast
 

 




pctdiff

 




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_______________________________________________ Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer The information in this e-mail is intended only for the person to whom it is addressed. If you believe this e-mail was sent to you in error and the e-mail contains patient information, please contact the Partners Compliance HelpLine at http://www.partners.org/complianceline . If the e-mail was sent to you in error but does not contain patient information, please contact the sender and properly dispose of the e-mail.

_______________________________________________ Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer The information in this e-mail is intended only for the person to whom it is addressed. If you believe this e-mail was sent to you in error and the e-mail contains patient information, please contact the Partners Compliance HelpLine at http://www.partners.org/complianceline . If the e-mail was sent to you in error but does not contain patient information, please contact the sender and properly dispose of the e-mail.