I have another question about the statistical parametric map, which is the value of the p considered significant? Thanks Valentina
-----Original Message----- From: Doug Greve [mailto:greve@nmr.mgh.harvard.edu] Sent: Tuesday, September 19, 2006 6:40 PM To: Durastanti, Valentina (NIH/NINDS) [F] Cc: Bruce Fischl; Graham Wideman; freesurfer@nmr.mgh.harvard.edu Subject: Re: [Freesurfer] visualization of statistical analysis
Durastanti, Valentina (NIH/NINDS) [F] wrote:
Valentina
I created a statistical parametric map and I visualized it on tksurfer. I didn't use a variable and I used a contrast vector (1 -1) because I was interested in knowing the difference between two classes. I'd like to know how I can interpreter the two colors, in other words do the two different colors means that there is a difference two classes? (i.e.
the
thickness of the cortex is greater in class one than class two: color red; the thickness of the cortex is lower in class one than class two: color blue).
This interpretation is correct.
Another question is: why I need to create an average subject? Just to visualize the surface or it is used for the statistical analysis
somhow?
It is mostly for display purposes, but it is also used to compute the number of nearest neighbor iterations from the FWHM when performing surface smoothing. But I think it won't make much of a difference.
Thanks Valentina
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