On Sun, Sep 15, 2013 at 2:28 PM, Douglas Greve <greve@nmr.mgh.harvard.edu> wrote:

There is not a way to do this using an FSGD and a DODS model. It will work if you change it to DOSS (if that is appropriate). Otherwise, you will need to create your own design matrix and feed it to mri_glmfit with --X
doug

On 9/13/13 10:21 PM, ye tian wrote:
Dear Freesurfers,

I am studying how the practice of meditation affects cortical thickness. I have two types of meditations, and I also know for how many years each mediator has meditated. Therefore, ideally I would like my categorical factor to be meditation (control, meditation1 and meditation2), and continuous factor to be the number of years of meditation. This design, of course, has a problematic column of zeros, which corresponds to the slope of the control (a non-meditator has meditated for 0 years).

Does freesurfer has a way out of this problem? For example, I have came across pseudoinverse methods in literature?

Any suggestion is highly appreciated.

Thank you very much!

Sincerely,

Ye
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