Dear FSL Experts,
Could you please let me know the answers? Your help is greatly appreciated. Thank you.
1. p.20 "An example experiment An FMRI adaptation of a classical PET experiment": What is 6 sec ISA?
2. p.30 "Building a model": “This time we used the onset times for the shadowing events to get the predicted brain response for those.” Could you please let us know the missing the ending part?
3. p.31 “Building a model”. “And we can look for voxels that match that”. What is the missing the ending part?
4. p.33 “Slight detour: Making regressors”. What is mean by “Sub-sample at Tr of experiment”?
5. p.49 "t-contrasts" There are three red arrows from "The Model", "The Contrast" and "and the Residual Error". By "Depends on", do they mean std(COPE) depends on these three factors?
6. p.49-50 How to go from t, COPE and std(COPE) to the brain images in the next slide?
7. p.49 Residual error = standard error = standard derivation?
8. p.61 "t-contrasts": the author asks "Why [1 –1] instead of [1 0]?" So why?
10. p.69 "F-contrasts": it states that F = (Ssr-Sse)/Sse = (large arrow – small arrow / small arrow). What do those double arrows of different lengths mean?
11. p.69 "F-contrast": What is Reduced Model? Why the blue line next to the reduced model's matrix is flat?
12. p.71 "F-contrast vs Mean activation": Why "Most probably not significant"?
13. p.81 In "Choosing High-Pass Filter Cut-off", under "Example: Boxcar EV with period 100s" "Negligible effect on EV, so use cut-off of 100s" Could you please let me know why negligible and why use cut-off of 100s?
14. Same page under "Example: Boxcar with period 250s" "Substantial effect on EV" Could you please explain why substantial effect and why a cut-off of 100s is chosen?
15. Similarly, under the rightmost design matrix, it states "Negligible effect on EV, so use cut-off of 250s". Please let us know why negligible and why use a cut-off of 250s.
16. p.82 and p.84, 85: What is autocorrelation? Can't find it in fMRI books.
17. p.84 FMRIB's Improved Linear Modelling (FILM): Could you please explain what "Apply filter to data and design matrix and refit" is?
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