Alexandru,

The p-values displayed in qdec are actually -log10(p), so a value of 5 is 0.00001, p of 3 would be 0.001, etc.

The coordinates shown are freesurfer 'surface' coordinates, and do not have much value outside of freesurfer. qdec will be changed to show talairach coords in the future. You can get the tal coords in a roundabout way by loading the fsaverage surface in tksurfer: tksurfer fsaverage rh inflated and using the Tools->Select Vertex option, selecting the vertex number you see in qdec, and tksurfer will show the tal coords for that point.

Nick

On Fri, 2008-11-14 at 19:25 +0000, Alexandru Hanganu wrote:

Dear Freesurfer users,

We have made an analysis of 2 groups (i.e. patients, healthy subjects) in order to see the cortical thickness differencies. We have introduced these groups into Qdec. The results showed p-values on a scale from -5 to +5 and the X coordinates of the right hemisphere were negative. Two questions: - are the p-values actually t-values ? - normally the X coordinates of the right hemisphere should be positive. Any ideas why they are negative ?

Thank's a lot for any help.

Best regards, Dr. Alexandru Hanganu ___________________________________ Department of Neurology, Schleswig-Holstein University Hospital, Kiel Campus Arnold-Heller-Str. 3, building no. 41 D-24105 Kiel, Germany.

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