I have decided now to not control for ICV or total gray matter volume when looking at cotrical thickness but to control for total gray matter volume when looking at surface area. Does that sound about right?
Cheers, Clara ----- Ursprüngliche Mail ----- Von: "Arkadiy Maksimovskiy" <arkad...@bu.edu> An: freesurfer@nmr.mgh.harvard.edu Gesendet: Samstag, 2. Juli 2016 18:36:51 Betreff: Re: [Freesurfer] controlling for total gray matter volume Hi Clara, If I am understanding your question correctly, you don't need to control for brain volume when looking at thickness analyses. See quote below from this link: http://www.freesurfer.net/fswiki/eTIV "Note that this correction is only useful in situations where the structure scales with head size. Outside of this, correction just adds noise, or provides inaccurate data. In the case of the measures from Freesurfer, one would apply correction to the volume measures and not thickness measures. This is because volume scales with head size which is mostly due to changes in surface area, whereas thickness alone scales to a much less degree." Best, Arkadiy On Sat, Jul 2, 2016 at 12:00 PM, < freesurfer-requ...@nmr.mgh.harvard.edu > wrote: Send Freesurfer mailing list submissions to freesurfer@nmr.mgh.harvard.edu To subscribe or unsubscribe via the World Wide Web, visit https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer or, via email, send a message with subject or body 'help' to freesurfer-requ...@nmr.mgh.harvard.edu You can reach the person managing the list at freesurfer-ow...@nmr.mgh.harvard.edu When replying, please edit your Subject line so it is more specific than "Re: Contents of Freesurfer digest..." Today's Topics: 1. controlling for total gray matter volume (Clara K?hn) 2. cotrolling for total gray matter volume (Clara K?hn) ---------------------------------------------------------------------- Message: 1 Date: Thu, 30 Jun 2016 15:19:43 +0200 (CEST) From: Clara K?hn < cku...@cbs.mpg.de > Subject: [Freesurfer] controlling for total gray matter volume To: Freesurfer support list < freesurfer@nmr.mgh.harvard.edu > Message-ID: < 600644700.119350.1467292783757.javamail.zim...@cbs.mpg.de > Content-Type: text/plain; charset=utf-8 Dear FreeSurfer experts, I would like to look at longitudinal thickness data and want to control for total gray matter volume. Should I use that information from the CROSS before anything has been registered and smoothed or from the LONG after they have been registered to the BASE? Also I was wondering if it is useful to control for total gray matter volume when looking at surface area? Thanks for your help! Clara ------------------------------ Message: 2 Date: Thu, 30 Jun 2016 15:01:06 +0200 (CEST) From: Clara K?hn < cku...@cbs.mpg.de > Subject: [Freesurfer] cotrolling for total gray matter volume To: Freesurfer support list < freesurfer@nmr.mgh.harvard.edu > Message-ID: < 1473114832.117985.1467291666701.javamail.zim...@cbs.mpg.de > Content-Type: text/plain; charset=utf-8 Dear FreeSurfer experts, I would like to look at longitudinal thickness data and want to control for total gray matter volume. Should I use that information from the CROSS before anything has been registered and smoothed or from the LONG after they have been registered to the BASE? Also I was wondering if it is useful to control for total gray matter volume when looking at surface area? Thanks for your help! Clara -- Clara K?hn, Phd Student Max-Planck-Institute for Human Cognitive and Brain Science Department of Neuropsychology Stephanstrasse 1A 04103 Leipzig, Germany Phone: +49 341 - 9940 2271 Fax: +49 341 - 9940 2260 Web: www.cbs.mpg.de E-Mail: cku...@cbs.mpg.de ------------------------------ _______________________________________________ Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer End of Freesurfer Digest, Vol 149, Issue 6 ****************************************** 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. _______________________________________________ Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer
