Dear FSL experts,
I used FSL 5.0.1 in an iMac machine with 16GB of RAM to run 3rd level FEAT analyses using fixed-effects (FE) in one and mixed-effects (ME - FLAME 1) with outlier de-weighting in the other. I was expecting to see more and/or bigger clusters of activation in the FE analysis compared to the results from ME. However this is not the case. For example, that are contrasts that showed no clusters in FE but did have them in ME. Additionally, the results for ME showed "nan" for the columns "P" and "- log10(P)", and the number of clusters found was considerably big (up to 156 for some contrasts) and many clusters had only 1 voxel in them. The log files did not show any blatant errors as far as I could tell.
I attached here as an example the "cluster_zstat4_std.txt" file from the ME analysis (for FE no clusters were found for this contrast). What are your thoughts about these differences?
Thank you.
Estephan Moana, D.D.S., M.S.
Ph.D. Candidate
Clinical Fellow, Oral & Maxillofacial Pain Program
Regional Center for Neurosensory Disorders
UNC School of Dentistry
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Cluster Index Voxels P -log10(P) Z-MAX Z-MAX X (mm) Z-MAX Y (mm) Z-MAX Z (mm) Z-COG X (mm) Z-COG Y (mm) Z-COG Z (mm) COPE-MAX COPE-MAX X (mm) COPE-MAX Y (mm) COPE-MAX Z (mm) COPE-MEAN
23 41 nan nan 3.07 -47 -8 13 -46.6 -7.65 13.7 18.2 -47 -8 13 14.4
22 41 nan nan 2.63 -41 41 -7 -40.8 38.7 -5.58 24.9 -42 43 -7 17.6
21 27 nan nan 2.59 59 -37 17 59.6 -37.2 17 20.2 59 -38 17 18.1
20 12 nan nan 2.52 -68 -34 15 -67.8 -33.5 14.9 27.7 -67 -34 15 23.4
19 9 nan nan 2.44 67 -18 7 67.1 -17.7 6.56 19.5 68 -18 7 17.4
18 9 nan nan 2.53 -60 -54 6 -60.3 -54.6 6.56 21.6 -59 -54 6 20.2
17 8 nan nan 2.62 -42 -52 12 -42.5 -51.9 11.9 15 -44 -51 13 13.2
16 7 nan nan 2.56 68 -17 37 68 -17 38 15.7 68 -16 38 15
15 5 nan nan 2.45 56 47 1 56 46.4 0.805 21.4 56 46 2 21.2
14 5 nan nan 2.43 -50 16 1 -50 15.8 1.59 15.7 -50 16 0 14.1
13 3 nan nan 2.45 -18 15 63 -17.3 15 62.7 12.6 -17 15 63 12.2
12 3 nan nan 2.42 55 -49 56 55.3 -48.3 56 19 55 -49 56 17.9
11 3 nan nan 2.51 -64 -3 5 -64 -3.65 4.68 38.4 -64 -3 5 37.8
10 2 nan nan 2.38 67 -18 42 67 -18.5 42 14.7 67 -18 42 14.4
9 2 nan nan 2.32 -55 -37 28 -54.5 -37 28.5 18.8 -54 -37 29 18.7
8 2 nan nan 2.35 64 -36 20 64 -36 19.5 19.2 64 -36 20 18.9
7 2 nan nan 2.31 -37 39 13 -37 39.5 13 12 -37 39 13 11.9
6 2 nan nan 2.33 65 -36 1 64.5 -36.5 1.5 15.8 65 -36 1 15.8
5 1 nan nan 2.34 -48 4 56 -48 4 56 22.1 -48 4 56 22.1
4 1 nan nan 2.3 61 -7 47 61 -7 47 17.7 61 -7 47 17.7
3 1 nan nan 2.31 68 -12 35 68 -12 35 17.7 68 -12 35 17.7
2 1 nan nan 2.3 -47 -10 18 -47 -10 18 9.98 -47 -10 18 9.98
1 1 nan nan 2.32 -65 3 1 -65 3 1 21.2 -65 3 1 21.2
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