Re: [Freesurfer] Interpreting white matter regressor dat file

Hi Doug,

These are the first few lines of the wm.dat.pca-stats.dat file:

1 143481216.00 143481216.00 4.06 4.06 2 77359288.00 220840504.00 2.19 6.25 3 42542944.00 263383448.00 1.20 7.46 4 26329902.00 289713350.00 0.75 8.20 5 21830372.00 311543722.00 0.62 8.82 6 19145688.00 330689410.00 0.54 9.36 7 18512178.00 349201588.00 0.52 9.89

According to the functional connectivity tutorial (http://surfer.nmr.mgh.harvard.edu/fswiki/FsFastFunctionalConnectivityWalkthr...), usually only the first 5 components are used for white matter regression. However, if I understand correctly, it looks like the first five components only remove ~8.82% cumulative variance, is that correct? If so, how should I go about choosing components for white matter regression?

Thanks,

Afsana

______________________________ Afsana Afzal Clinical Research Coordinator Massachusetts General Hospital Division of Neurotherapeutics Department of Psychiatry: Neurosciences 149 13th St, Room 2612 Charlestown, MA 02129 Phone: 617-643-5129 Fax: 617-726-4078

________________________________________ From: freesurfer-bounces@nmr.mgh.harvard.edu [freesurfer-bounces@nmr.mgh.harvard.edu] on behalf of Douglas N Greve [greve@nmr.mgh.harvard.edu] Sent: Wednesday, January 13, 2016 12:36 PM To: freesurfer@nmr.mgh.harvard.edu Subject: Re: [Freesurfer] Interpreting white matter regressor dat file

here you go (1) component number (2) variance spanned by that component (3) cumulative variance spanned up to that component (4) percent variance spanned by that component (5) cumulative percent variance spanned up to that component

On 01/13/2016 09:56 AM, Afzal, Afsana wrote:

Hi,

I have generated white matter regressor files for resting state analysis using fcseed-config and fcseed-sess. The resulting files include: wm.dat, wm.dat.pca-stats.dat and wm.dat.log.

How do I interpret the wm.dat.pca-stats.dat file? There are 388 numbered rows (I'm guessing one per acquisition since # of acquisitions is 388?) and five columns. What do the columns represent?

Thanks for your help!

• Afsana

---

*Afsana Afzal* Clinical Research Coordinator Massachusetts General Hospital Division of Neurotherapeutics Department of Psychiatry: Neurosciences 149 13th St, Room 2612 Charlestown, MA 02129 Phone: 617-643-5129 Fax: 617-726-4078

---

Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer

-- Douglas N. Greve, Ph.D. MGH-NMR Center greve@nmr.mgh.harvard.edu Phone Number: 617-724-2358 Fax: 617-726-7422

Bugs: surfer.nmr.mgh.harvard.edu/fswiki/BugReporting FileDrop: https://gate.nmr.mgh.harvard.edu/filedrop2 www.nmr.mgh.harvard.edu/facility/filedrop/index.html Outgoing: ftp://surfer.nmr.mgh.harvard.edu/transfer/outgoing/flat/greve/

_______________________________________________ Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer