Re: [Freesurfer] mergecontrasts-sess group map

2012-11-29 Thread Douglas N Greve
You'll have to run mri_vol2surf on each one separately to bring it into the fsaverage space, then mri_concat to stack all of the maps into one file. At that point you can compute a mean (also with mri_concat). Generally, one does not do group analysis on sig maps though. doug On 11/27/2012 05

Re: [Freesurfer] mergecontrasts-sess group map

2012-11-29 Thread Alexandra Tanner
Hi Doug, Thanks for the response! Just out of curiosity, what map is typically used for group analyses? Should I have used a map other than sig on the individual subject level as well? Thanks! Alex > > You'll have to run mri_vol2surf on each one separately to bring it into > the fsaverage spac

Re: [Freesurfer] mergecontrasts-sess group map

2012-11-29 Thread Douglas N Greve
Usually the contrast effects size (ces) (in SPM this is the CON image, in FSL it is the COPE image). Univariate maps are usually passed up to the group level (the conjunction done with mergecontrasts is multivariate). doug On 11/29/2012 01:05 PM, Alexandra Tanner wrote: > Hi Doug, > > Thanks fo

Re: [Freesurfer] mergecontrasts-sess group map

2012-11-29 Thread Alexandra Tanner
Thanks for the clarification! So I will rerun mergecontrasts-sess using the ces image on my subjects and then run mri_vol2surf and mri_concat to get the group map. Thanks for your help! Best, Alex > Usually the contrast effects size (ces) (in SPM this is the CON image, > in FSL it is the COPE ima

Re: [Freesurfer] mergecontrasts-sess group map

2012-11-29 Thread Douglas N Greve
Hi Alex, unfortunately, you cannot compute a conjunction with the CES. That's the problem with trying to do group-wise multi-variate analysis. Another thing you can do is to do a group analysis with each contrast separately, then do a conjunction of the group sig maps. doug On 11/29/2012 03:39

Re: [Freesurfer] mergecontrasts-sess group map

2012-11-30 Thread Alexandra Tanner
Hi Doug, So if I run a group analysis with each contrast separately, would I then be running mri_concat to do a conjunction of the group sig maps? Also, can I merge more than 2 contrasts at once when using mri_concat? Thanks! Alex > > Hi Alex, unfortunately, you cannot compute a conjunction with

Re: [Freesurfer] mergecontrasts-sess group map

2012-11-30 Thread Douglas N Greve
yesand yes doug On 11/30/2012 10:53 AM, Alexandra Tanner wrote: > Hi Doug, > > So if I run a group analysis with each contrast separately, would I then > be running mri_concat to do a conjunction of the group sig maps? Also, can > I merge more than 2 contrasts at once when using mri_concat? Thanks