Hi,
My group analysis of fMRI showed subthreshold activations in my hypothetical regions. To reduce the effect of global multiple comparisons, I want to confine my contrast results in gray mater (GM) only, i.e., excluding voxels in white mater and CSF. Two questions:
(1) Can any one give me a hint about how to get the GM mask? My idea is to do segmentation for each subject's T1-weighted image , normalised their T1 to standard space, and then average all normalised T1 images.
(2) How to confine multiple comparisons in this GM mask? Is it just an ROI process (i.e., first use uncorrected p< 0.005 or 0.001, select SVC button, and then select this GM mask) ? Or, after selecting Results, use this GM mask as inclusive mask, and then select FWE?
Thanks.
Mike
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