Hello Freesurfer Developers,
I am having an issue with values of 0 in certain areas of the visual cortex in my beta.mgh files.
I am looking at the effect of age on grey/white matter signal intensity contrast (grey devided by white times 100) with gender as a regressor. I ran mri_glmfit with the DODS Matrix 0 0 0.5 0.5 CLASS 1 and 2 were males and females respectively and age in months was the variable.
When I look at the beta.mgh files in Freeview there are identical parts of surface which contains 0 even tho there are contrast values in those areas in the contrast surface maps. If I understood correctly the 2 first beta files should be the average contrast for males and females at offset? and the 3rd and 4th should be the slope? So at least the first two files should not contain 0 other than in the medial wall.
Any idea what I might be doing wrong?
Thank you in advance! Cheers, Linn