Hi Oerjan,
yes, but I don't see a way to do that with the longistudinal stream. You
could, however, first register surfaces across twin pairs and then go to
fsaverage. You could fix cortical parcellations fixed across twin pairs
on the target twin and compare ROI values across twins. You could also
compute difference in thickness for each twin pair first and then
compare across groups on fsaverage.
Yet for all this you'd have to select one of the twins as registration
target. This would not bias your data as you can select the target randomly.
Best, Martin
On 11/10/2015 03:58 AM, Örjan de Manzano wrote:
Thank you for the quick reply!
I've been elaborating with a ROI-based approach for VBM where I first
create an unbiased template for each MZ-pair (non-linear registration;
ANTS SyN); second, create a group template in MNI-space where ROIs are
defined; third, warp each pair template to the group template and use
the inverse transformations to get ROIs to pair-space where data are
obtained (from the modulated images native->pair). With this approach,
deformations are smaller and specific to each paired comparison and I
do not have to smooth the data as much. From what I can tell, it
outperforms the traditional group analysis when using MZ twins. Would
it make sense to try something similar with the cortical thickness
analysis in Freesurfer?
Best,
Örjan
------------------------------------------------------------------------
*From:* freesurfer-boun...@nmr.mgh.harvard.edu
[freesurfer-boun...@nmr.mgh.harvard.edu] on behalf of Martin Reuter
[mreu...@nmr.mgh.harvard.edu]
*Sent:* Wednesday, November 04, 2015 14:55
*To:* Freesurfer support list
*Subject:* Re: [Freesurfer] applying longitudinal processing on twins
Hi Oerjan,
yes, MZ twins are very similar (InfoAd: are you familiar with our
BrainPrint NeuroImaging paper where we compare MZ and DZ brain shapes:
http://www.sciencedirect.com/science/article/pii/S1053811915000476
http://reuter.mit.edu/blue/papers/wachinger-brainprint15/wachinger-brainprint15.pdf
).
Anyway, I doubt the longitudinal stream is going to work for this, as
it is really designed for longitudinal and not across subject
situations (even with MZ twins I expect differences to be too large).
Even if a few cases work, there will be too many that fail.
Best, Martin
On 11/04/2015 05:13 AM, Örjan de Manzano wrote:
Dear FreeSurfers,
I'm about to analyze cortical thickness in monozygotic twins
discordant for certain expertise. The within-pair similarities in
brain morphology are striking (e.g. twin1 x twin2 intracranial volume
correlation r=.99) and you could easily play a memory game with the
images. Nonetheless, there are notable within-pair differences in
gyrification etc. I'm trying to figure out if the longitudinal
stream, or some version of it, might still be a viable option in this
situation. The sample is fairly small and I want to do what I can to
maximize sensitivity. Do any of you have experience with a similar
data set or ideas/opinions/recommendations?
Best regards,
Örjan
_______________________________________________
Freesurfer mailing list
Freesurfer@nmr.mgh.harvard.edu
https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer
--
Martin Reuter, PhD
Assistant Professor of Radiology, Harvard Medical School
Assistant Professor of Neurology, Harvard Medical School
A.A.Martinos Center for Biomedical Imaging
Massachusetts General Hospital
Research Affiliate, CSAIL, MIT
Phone: +1-617-724-5652
Web :http://reuter.mit.edu
_______________________________________________
Freesurfer mailing list
Freesurfer@nmr.mgh.harvard.edu
https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer
--
Martin Reuter, PhD
Assistant Professor of Radiology, Harvard Medical School
Assistant Professor of Neurology, Harvard Medical School
A.A.Martinos Center for Biomedical Imaging
Massachusetts General Hospital
Research Affiliate, CSAIL, MIT
Phone: +1-617-724-5652
Web : http://reuter.mit.edu
_______________________________________________
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.
