It might help to show an image.
Have you looked at the voxel time series in that scan? Sometimes you can see the artifact better in the time series in some of the over-active voxels than ion a viewer.
FSLview lets you see the time series.
Best of luck,
Colin Hawco, PhD
Neuranalysis Consulting
Neuroimaging analysis and consultation
www.neuranalysis.com
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-----Original Message-----
From: FSL - FMRIB's Software Library [mailto:[log in to unmask]] On Behalf Of Yelena Bodien
Sent: July-14-17 12:43 PM
To: [log in to unmask]
Subject: [FSL] Striping artifact and odd zstat maps
Dear FSL experts,
In our study we acquire 8 runs of fMRI data (4 tasks, each repeated twice). For one subject, in one of the runs, we see a very strange first-level stat1 map- the entire superior aspect of the brain is positively activated (this is with esentially no statistical threshold) and the inferior aspect is completely deactivated. There is a distinct "line" of no activation between the activated and deactivated areas. Typically, we see zmaps that have a random distribution of activation and deactivations (before thresholding) so I'm not sure what would be causing this artifact. Another odd thing about this particular run is that the original EPI's look normal in FSview but have a striping artifact in other viewers (e.g., FreeView). Does anyone have any experience with this kind of artifact?
Thanks,
Yelena
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