[caret-users] A scatterbrain issue -- with apologies to the resident punmaster :)

[Donna Dierker]

Hi Jay,

How's it goin', eh?

Some reasons come to mind (e.g., average surface doesn't intersect the 
volume well), but I'd prefer to have a look myself first.  Could you 
upload the SPM5 volume here:

http://pulvinar.wustl.edu/cgi-bin/upload.cgi

Alternatively, you could send a few captures showing the activity mapped 
onto the inflated surface (unthresholded), along with a corresponding 
volume view showing the unthresholded SPM5 volume overlaid on the 
avg152T1 anatomical, and SPM2 average surface contour toggled on.

If it is an issue with the volume not intersecting the average surface 
well, you might consider using MCW's brainfish algorithm.  Another 
alternative is smoothing on the surface after mapping.

Donna

On 01/28/2008 10:58 AM, Jay Hegdé wrote:
> Hi,
>    I'm using Caret 5 to visualize SPM5 statistical maps (in NIfTI 
> format and MNI space) on PALS surfaces using your SPM2 template and 
> multifiducial mapping.
>
>    It works great, except that some of the ROIs that are contiguous in 
> the original map (where the usual requirement was that all the voxels 
> of a given ROI be contiguous) appear highly scattered and 
> non-contiguous on the PALS surface.
>
>    Checking the Interpolate box in the Display Control window helps, 
> but not much.  (Besides, I'm not at all confident that interpolating 
> is the right thing to do in my case.)  The problem occurs for all PALS 
> surfaces I've tried (flat, fiducial, inflated or very inflated) and 
> regardless of whether a given ROI is in a deep sulcus or on a gyrus 
> (as determined by hacking the original map).  So I don't think this is 
> an artifact of surface inflation per se, or even of the size of the ROI.
>
>    Could you please give me a sense for why this happens and what if 
> anything can be done to fix this?
>
>    Thank you very much.
>    Jay Hegdé
>    University of Minnesota
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