Dear FSLs,
I would like some advices regarding my MSc project. In particular, I want to study the functional connectivity of RSNs (mainly the DMN) in patients with posterior cortical atrophy (PCA) (#8) and healthy controls (#15). The steps that I have done are:
1) Apply a band pass temporal filter (0.01-0.08 Hz)
2) concat MELODIC using the temporal filtered data from both controls + PCA patients
- no high pass filter
- delete 6 first volumes
- spatial smoothing 7mm
- manually select #components (#25)
3) Dual regression using dual_regression script
-n_perm= 5000
- contrasts : a) Controls > PCA b) PCA > Controls, c) mean Controls d) mean PCA
1 -1
-1 1
1 0
0 1
However, when I look on the results I cannot see any significant difference, only in the Dorsal visual stream and a small area in the DMN but in a position completely different from the activated regions (MTLs, PCC etc.)
In addition, the " mean Controls" and "mean PCA" maps after the DR are different from the "average" components that I found using two separate concat MELODIC on PCA patients and Controls groups individually. Also, the DMN component of Controls seems that has differences (regarding the # voxels in PCC and MPFC ) compared to that of the posterior cortical atrophy patients when I perform separately the concat MELODIC. So I suspect that it would be better if I perform two separate concat MELODIC but then I do not have any idea how I could perform the dual regression.
Thank you very much for your time. Any advice/comment would be very useful.
Kind Regards,
Ioannis Giapitzakis
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