Hi Bruce, I checked the surface of every subject with tksurfer, inaccuracy's were founded in 13 of 140 subjects. These subjects were manually edited with control points and pial edits. Then i start recon-all on the subjects with edits again. After these procedure tksurfer showed a correct segmentation. Is that the correct procedure for checking inaccuracy's? Or do i need to check more?
http://surfer.nmr.mgh.harvard.edu/fswiki/FsTutorial/ControlPoints http://surfer.nmr.mgh.harvard.edu/fswiki/FsTutorial/PialEdits Many thanks, Stan ________________________________________ From: Bruce Fischl [fis...@nmr.mgh.harvard.edu] Sent: 05 February 2013 15:54 To: Berg, S.F. van den Cc: Freesurfer@nmr.mgh.harvard.edu Subject: Re: [Freesurfer] Difficult results from our PD data Hi Stan we have found positive correlations between performance (in this case CVLT) and thickness, so it is certainly possible. And negative correlations aren't necssarily false - you could certainly imagine that successful pruning for example could help performance. Have you visually inspected the surfaces for accuracy? cheers Bruce On Tue, 5 Feb 2013, Berg, S.F. van den wrote: > > > Dear Freesurfer experts, > > > > We investigated the relation between cortical thickness and performance on > several cognitive tasks within a large group of > Parkinson?s disease patients, but are slightly puzzled by the results. We > obtained several, both in the vertex-wise analysis > in qdec and in the SPSS analysis in the a-priori parcelated areas, negative > correlations (i.e. better performance relates > to a thinner cortical area) for all our neuropsychological tasks. These > negative correlations were unexpected and we are > having a hard time interpreting them. After correcting for multiple > comparisons, all effects failed to reach the > statistical threshold, rendering no results at all. When we compared our > patient group on a structural level with healthy > controls, we did find expected results that made sense. > > We also ran the exact same analyses (same group, same data) in VBM and there > found several positive task-related > correlations in expected areas. > > We noticed that in previous literature almost no studies investigated the > relation between cortical thickness and > cognitive task-performance. This made us wonder whether Freesurfer is suited > for these correlation-based analyses, or is > it better to be used in between group analyses? And do you have any idea on > how to explain our negative correlations? Is > it possible we might have done something wrong? > > > > Many thanks, > > > > Stan > > > 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
