External Email - Use Caution        

Hi Doug,

The FSGD looks like the attached. For the contrast: [ 0 0 0 0 0.5 -0.5 -0.5 0.5 0 0 0 0], to model the 3-way interaction between Class and the new multiplied continuous interaction variable controlling for eTIV.

That brainmap, where we multiply the two continuous variables, is not as robust as the original one where I tried to do the 3-way interaction between the 3 variables (2 continuous, 1 categorical (class)). So I really wonder what it was actually doing/plotting on the surface exactly? (ROIa x ROIb x class + eTIV:  [0 0 0 0 0.25 -0.25 -0.25 0.25 0.25 -0.25 -0.25 0.25 0 0 0 0]). Was it considering every row of the continuous variable as a category or? Would be great to be able to use that map (with the covariates normalized).

Thank you so much for your help!

All the best,

Fred


On Mon, May 1, 2023 at 8:48 AM Douglas N. Greve <dgreve@mgh.harvard.edu> wrote:

        External Email - Use Caution        

not sure, what you're new FSGD is

On 4/28/2023 1:23 PM, Federico Uquillas wrote:

        External Email - Use Caution        

Thank you so much!

Okie doke. 
So then, for an interaction between gender x handedness x ROIsInteractionTerm (continuous), controlling for eTIV, the contrast would be the following?

[ 0 0 0 0 0.5 -0.5 -0.5 0.5 0 0 0 0]


All the best,

Fred 

On Apr 28, 2023, at 10:30 AM, Douglas N. Greve <dgreve@mgh.harvard.edu> wrote:

        External Email - Use Caution        

The method you describe is only for discrete variables, not continuous ones. The traditional method for continuous variables is to create a new variable where you multiply them together. You should normalize you continuous variables too (ie, subtract the mean and divide by the stddev).

On 4/24/2023 8:52 PM, Fred d'Oleire Uquillas wrote:

        External Email - Use Caution        

Dear Fs support,

If I have the following FSGD with 4 classes and 3 variables, and I'd like to run an interaction of ROIa x ROIb controlling for the third covariate (eTIV), would I use the following contrast?

[0 0 0 0 0.25 -0.25 -0.25 0.25 0.25 -0.25 -0.25 0.25 0 0 0 0]

For the interaction of ROIa x ROIb x class + eTIV.

Thank you so much in advance for your help!

All the best,

Fred




_______________________________________________
Freesurfer mailing list
Freesurfer@nmr.mgh.harvard.edu
MailScanner has detected a possible fraud attempt from "secure-web.cisco.com" claiming to be https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer

_______________________________________________
Freesurfer mailing list
Freesurfer@nmr.mgh.harvard.edu
MailScanner has detected a possible fraud attempt from "secure-web.cisco.com" claiming to be 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 Mass General Brigham Compliance HelpLine at MailScanner has detected a possible fraud attempt from "secure-web.cisco.com" claiming to be https://www.massgeneralbrigham.org/complianceline MailScanner has detected a possible fraud attempt from "secure-web.cisco.com" claiming to be MailScanner has detected a possible fraud attempt from "secure-web.cisco.com" claiming to be MailScanner has detected a possible fraud attempt from "secure-web.cisco.com" claiming to be <https://www.massgeneralbrigham.org/complianceline> .
Please note that this e-mail is not secure (encrypted).  If you do not wish to continue communication over unencrypted e-mail, please notify the sender of this message immediately.  Continuing to send or respond to e-mail after receiving this message means you understand and accept this risk and wish to continue to communicate over unencrypted e-mail. 

_______________________________________________
Freesurfer mailing list
Freesurfer@nmr.mgh.harvard.edu
MailScanner has detected a possible fraud attempt from "secure-web.cisco.com" claiming to be https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer

_______________________________________________
Freesurfer mailing list
Freesurfer@nmr.mgh.harvard.edu
MailScanner has detected a possible fraud attempt from "secure-web.cisco.com" claiming to be 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 Mass General Brigham Compliance HelpLine at MailScanner has detected a possible fraud attempt from "secure-web.cisco.com" claiming to be https://www.massgeneralbrigham.org/complianceline <MailScanner has detected a possible fraud attempt from "secure-web.cisco.com" claiming to be https://www.massgeneralbrigham.org/complianceline> .
Please note that this e-mail is not secure (encrypted).  If you do not wish to continue communication over unencrypted e-mail, please notify the sender of this message immediately.  Continuing to send or respond to e-mail after receiving this message means you understand and accept this risk and wish to continue to communicate over unencrypted e-mail.