Hi Dan, it just gets the sign of the contrast it was computed from. You can just take the absolute value. doug
On 05/24/2013 03:58 PM, dgw wrote: > Hi, > > I am trying to compare the quality of fMRI data with different > artifact inducing objects in the magnet. I ran expanding and > contracting rings and followed the retinotopy fsfast analysis in > FreeSurfer 5.1.0. I am trying to compare the data by looking at the > sig.nii.gz (which from the website should correspond to the voxel-wise > significances) with the different artifacts. I am not sure though how > to interpret the negative values for a retinotopy analysis? Can > someone clarify what the negative values represent. I would have > expected the significance to only be positive, as there isn't a > traditional contrast in the smoothly varying stimulus. > > Thanks! > Dan > > > _______________________________________________ > Freesurfer mailing list > Freesurfer@nmr.mgh.harvard.edu > https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer -- 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: https://gate.nmr.mgh.harvard.edu/filedrop2 www.nmr.mgh.harvard.edu/facility/filedrop/index.html Outgoing: ftp://surfer.nmr.mgh.harvard.edu/transfer/outgoing/flat/greve/ _______________________________________________ Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer 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.
