no, we didn't use the parcellations. We binarized the sulc and used positive/negative sulc to be sulcal/gyral
cheers, Bruce
On Wed, 13 May 2009, Dana W. Moore wrote:
Actually, I have also been looking for cortical thickness normative values. We have run our first few research subjects with FreeSurfer (a normal control and several patients with neurodegenerative disorders), and I wanted to see if the thickness values we're getting are in the normal range. I have two papers: Salat et al. (2004) and Fischl & Dale (2000) in Cerebral Cortex. The Fischl and Dale gives average thickness for gyral and sulcal regions. Am I correct to guess that the average gyral and sulcal regions are taken by averaging the individual gyral and sulcal units from the aparc.a2005s.stats files? The Salat et al. article gives a global thickness measure--I was wondering how I would calculate this?
Also, if thickness values are available for individual parcellation units and/or whole lobes, that would be very helpful as well. In particular, the lobes would be helpful, as well as ROIs most relevant for AD (e.g. entorhinal cortex and temporal pole [Desikan et al., 2009]).
Thanks, Dana
Message: 1 Date: Wed, 13 May 2009 08:54:59 -0400 (EDT) From: rahul@nmr.mgh.harvard.edu Subject: Re: [Freesurfer] Literature values for cortical thickness To: "Bruce Fischl" fischl@nmr.mgh.harvard.edu Cc: freesurfer@nmr.mgh.harvard.edu, Falk L?sebrink falk.luese@gmx.net Message-ID: 49194.70.23.239.45.1242219299.squirrel@mail.nmr.mgh.harvard.edu Content-Type: text/plain;charset=iso-8859-1
Hi Falk,
We do indeed have cortical thickness values for each of the parcellation units for a range of subjects (healthly elderly, middle age and young controls and Alzheimer's disease subjects). Which parcellation units are you looking for? A whole lobe?
Best,
rahul
Hi Falk,
we published some values in our Cerebral Cortex paper , but I suspect the effective thickness will vary a bit as a function of pulse sequence, and certainly it will vary with things like age. Rahul has probably tabulated by parcellation unit if that helps.
cheers Bruce
On Wed, 13 May 2009, Falk Lüsebrink wrote:
Hi everyone,
As I dont do a study in which I compare a group of subjects with some kind of abnormality with a control group I was looking for literature values for cortical thickness. The only paper I found which was written by von Economo et al. in 1925 doing a post-mortem analysis.
Are there any more recent sources available which maybe even cover in-vivo values for regional cortical thickness? Actually Im looking for average values across the whole lobes.
Thanks in advance,
Falk
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