which curvature values. Can you send the output?
On Fri, 26 May 2006, Fornito, Alexander wrote:
Sorry, got it wrong way around. Either way, when I run mris_anatomical_stats on labels that I have created, I tend to get positive values for mean curvature for labels of both gyral crowns or sulcal fundi. Are the curvature values provided by mris_anatomical_stats unsigned?
Alex Fornito M.Psych/PhD (clin. neuro.) candidate Melbourne Neuropsychiatry Centre and Department of Psychology National Neuroscience Facility The University of Melbourne Levels 2 & 3, Alan Gilbert Building 161 Barry St Carlton South Vic 3053 Australia Ph: +61 3 8344 1624 Fax: +61 3 9348 0469 email: alexander.fornito@wh.org.au
-----Original Message----- From: Bruce Fischl [mailto:fischl@nmr.mgh.harvard.edu] Sent: Thu 5/25/2006 9:09 PM To: Fornito, Alexander Cc: freesurfer@nmr.mgh.harvard.edu Subject: Re: [Freesurfer] ROI Curvature
Hi Alex,
the gyri will should have negative mean curvature and the sulci positive. You can overlay the ?h.curv map to check.
cheers, Bruce On Thu, 25 May 2006, Fornito, Alexander wrote:
Hi, I have some labels that I've drawn, which correspond to the gyral crown and sulcal fundus of a given ROI. From what I understand, mean curvature provides an index of the convexity/concavity of the region. I would therefore have expected high positive values in the gyral ROI to represent a steeper peak in the curvature of the crown, with values closed to zero representing a more flattened gyrus. Converseley, I would have thought low negative values for the fundus ROI would represent a steeper peak in the opposite direction, with values closer to zero again reflecting flattened curvature. In reality, the values I get for both sulcal and gyral labels (using mris_anatomical_stats) tend to be both positive. Hoping someone could tell me what I'm missing?
Thanks in advance, Alex
Alex Fornito M.Psych/PhD (clin. neuro.) candidate Melbourne Neuropsychiatry Centre and Department of Psychology National Neuroscience Facility The University of Melbourne Levels 2 & 3, Alan Gilbert Building 161 Barry St Carlton South Vic 3053 Australia Ph: +61 3 8344 1624 Fax: +61 3 9348 0469 email: alexander.fornito@wh.org.au
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