Dear users, I writhe in the hope somebody encountered a similar problem. I have individual normalized maps of intrinisc brain networks from a dual regression. This maps are projected back into individual subject space and further into individual surface space. Finally I normalize this maps into fslaverage and look at group differences in functional connectivity. I have following problem:the statistical results for the pDMN differ in surface space compared to SPM:While group A has increased functional connectivity compared to group B when i compare the dual regression maps in SPM (this result is in line with literature), group A has decreased functional connectivity compared to group B when i compare the dual regression maps in surface space. Me and the IT expert have checked the script and the test contrast and repeated the analysis several times, we could not find any evident error (example: subject order inverted., matrix code inverted) The steps I perform are the following:1. individual MELODIC to preprocess functional data2. bbregister is used to coregister the preprocessed functional data to anatomy. Functional data is not changed, just the transformation matrix is saved (register.dat). Following warning is found: "initial G-W contrast is negative, but expecting positive. If the mov data has a T1 contrast, re-run with --T1" . Is this relevant?3. Dual regression is performed with normalized functional data and maps are statistically evaluated4. Normalized dual regression maps are backprojected into native space by using the inverse normalization matrix derived from the first preprocessing through MELODIC5. vol2surf is used to project native space maps into individual surface space derived from freesurfer (using register.dat file) 6. mris_preproc and mri_glmfit are used to normalize the individual surface activation maps into fslaverage and the two sample ttest is performed. I am really wondering how the results can be inverted just in this SINGLE NETWORK, as they are comparable for other networks. The backprojection into native space is crucial for my research question. Hope is the last to die:)thanks and cheers, Lorenzo
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