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Dear all,
I’m in the process of switching from SPM2 to SPM8, and
I’m seeking help to explain differences in the results I get when I process
the same (individual subject) dataset with both suites. I’m using a
high-res EPI sequence (22 slices, voxel size = 2x2x2 mm, TR = 2000 ms, TE = 40
ms) with a limited FOV (I only capture the upper half of the brain) and the
following preprocessing algorithms and parameters:
Slice Timing (TR = 2, TA = 1.909, # slices = 22, slice order
= [2:2:22 1:2:22], ref slice = 11)
Realign and unwarp (defaults)
Smoothing (4.708 FWHM)
(No coregistration, normalization, or segmentation)
However, when I use the same data to set up and estimate the
1st-level model (I don’t use 2nd level—all my
analysis is within-subject), I get totally different activation maps in the
results for SPM8 compared to SPM2, even when using the exact same p value and cluster
size thresholds. Can someone help me to understand why this is and/or what
I may be doing wrong?
Thanks so much for your help in advance!
-Elyse