To clarify, I am piggy-backing on the retinotopic analysis to map out orientation preference with the travelling-wave method. We presented subjects with a rotating grating and right now I am simply interested in finding the voxels that have significant activity in response to any orientation. Now, when I load the sig.nii file under the 'polar' folder with MATLAB I see that each voxel has 2 values. I understand that these are the p-values for the real and imaginary components of the signal. Is there a way to put these 2 values together for my purposes? Is there a file somewhere in the pipeline that will give me the values I am looking for?

Thanks you for your help

Cesar


On Wed, Dec 4, 2013 at 10:14 AM, Douglas N Greve <greve@nmr.mgh.harvard.edu> wrote:

They are compared against 0 (ie, no change from baseline). The negatives just mean that the real component was negative
doug



On 12/03/2013 06:21 PM, Cesar Echavarria wrote:

So I want to figure out which voxels were modulated significantly by the orientation of our stimuli. Is this the right file to look at? If so what are the real and imaginary components compared against? I want to know to make sense of the negative values.

On Dec 3, 2013 5:52 PM, "Douglas N Greve" <greve@nmr.mgh.harvard.edu <mailto:greve@nmr.mgh.harvard.edu>> wrote:

      It is the -log10(pvalue) where pvalue is the p-value from the F-test
    of the real and imaginary components
    doug





    On 12/03/2013 05:41 PM, Cesar Echavarria wrote:
    > Hi freesurfers,
    >
    > I conducted a retinotopic analysis for one of my subjects. I was
    > wondering if any of you knew what is represented by the values
    in the
    > sig.nii file under the 'polar' directory that the process puts out.
    >
    > I appreciate your help!
    >
    > Cesar
    >
    >
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--
Cesar Echavarria
Research Assistant
Martinos Center for Biomedical Imaging, Harvard-MGH
Brain & Cognitive Sciences | MIT 2012