It should be roughly the sum of the dofs of the individual subjects. Why are you using a fixed-effects model? doug
SHAHIN NASR wrote: > Thanks Doug. Just one related question. Should I also generate a > new ffxdof.dat file for this map? I assumed that ffxdof depends on the > number of subjects (session) and since number of subjects (sessions) > is the same between the two groups then I can use those values, > generated by isxconcat-sess for either map1 or map2. Right? > > > > On Wed, Oct 19, 2011 at 1:33 PM, Douglas N Greve > <gr...@nmr.mgh.harvard.edu <mailto:gr...@nmr.mgh.harvard.edu>> wrote: > > Hi Shahin, it is not as simple as doing a subtraction of the > cesvar files. What you are trying to get is the expected variance > of your difference between the ces files (as a variance, it must > be positive). To get this you need > > cesvardiff = (cesvar1+cesvar2)/(2^2) > > The 2^2 is the number of inputs (2) squared. > > doug > > > SHAHIN NASR wrote: > > Hi, > > I have generated two different functional connectivity maps > for two different ROI-based seeds. These maps are based on > group-average of the same subjects (generated by using > separate isxconcat-sess commands ), and now I want to see the > difference map. To do so, I used mris_calc as below. > > mris_calc -o diff_map/rh.ces.nii map1/rh.ces.nii sub > map2/rh.ces.nii > > Also, to generate the rh.cesvar.nii file I used this command: > > mris_calc -o diff_map1/rh.cesvar.nii map1/rh.cesvar.nii > sub map2/rh.cesvar.nii > > But then when I used the glmfit with WLS option as below: > > > mri_glmfit --y rh.ces.nii --osgm --glmdir rh.ffx.osgm.wls > --nii --mask ../rh.mask.nii --yffxvar rh.cesvar.nii > --ffxdofdat ../ffxdof.dat --surf fsaverage rh --wls rh.cesvar.nii > > I faced an error saying: "Error: MRInormWeights: values less > than or eq to 0" which I assumed is related to an error in > rh.cesvar.nii file (am I right?). Would you tell me how can I > fix this problem? > > P.S.: please note that sequence of subjects and all MRI > parameters are exactly the same between the two maps. > > -- > Shahin Nasr > > PhD in Cognitive Neuroscience > Martinos Imaging Center, MGH > Harvard Medical School > > > -- > Douglas N. Greve, Ph.D. > MGH-NMR Center > gr...@nmr.mgh.harvard.edu <mailto:gr...@nmr.mgh.harvard.edu> > Phone Number: 617-724-2358 <tel:617-724-2358> Fax: 617-726-7422 > <tel:617-726-7422> > > Bugs: surfer.nmr.mgh.harvard.edu/fswiki/BugReporting > <http://surfer.nmr.mgh.harvard.edu/fswiki/BugReporting> > FileDrop: www.nmr.mgh.harvard.edu/facility/filedrop/index.html > <http://www.nmr.mgh.harvard.edu/facility/filedrop/index.html> > > > > 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. > > > > > -- > Shahin Nasr > > PhD in Cognitive Neuroscience > Martinos Imaging Center, MGH > Harvard Medical School > -- Douglas N. Greve, Ph.D. MGH-NMR Center gr...@nmr.mgh.harvard.edu Phone Number: 617-724-2358 Fax: 617-726-7422 Bugs: surfer.nmr.mgh.harvard.edu/fswiki/BugReporting FileDrop: www.nmr.mgh.harvard.edu/facility/filedrop/index.html _______________________________________________ Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer
