Hi Kevin, this sounds like a bias field problem. You can try manually selecting some control points in tkmedit near the calcarine, but make sure that the ones you pick are not partial-volumed (they must be completely within the white matter). Also, you want to pick ones that are below the intended value of 110 on the T1 image, otherwise it won't brighten things. You can then run mri_normalize with the -f $SUBJECTS_DIR/$subject/tmp/control.dat option to include the manually selected control points.
cheers, Bruce -------------------------------------------------------- Bruce Fischl email: [EMAIL PROTECTED] Mass. General Hosp. NMR Center. tel:(617)-726-4897 Rm. 2328, Building 149, 13th Street fax:(617)-726-7422 Charlestown, MA 02129 USA On Tue, 3 Jun 2003, Kevin H. wrote: > ok thanks doug > > also, i'm having trouble segmenting the white matter in the visual > cortex. (its too dark, almost as bright as the grey matter in the mid > brain) > we've averaged multiple scans but that doesn't seem to help. would > changing the normalization parameters in the Expert preferences help? > > thanks!!! >
