2*2 design

Submitted by Aaron_Hsiang on Tue, 07/09/2019 - 04:33

Dear teachers,

The design of our study is a two groups (14 patients vs. 14 controls)*two conditions (stimulation A vs. stimulation B) type, and according to Dr. Yan' s comments, we perfomed mixed effect analysis using DPABI (the latest version).  After GRF (voxel P=0.02, cluster P=0.05, two tails), two clusters connecting  ACC remained in condition T  map, while none remained in either group T or interaction F map (single tail). Meanwhile, we performed paired T test within each group based on corresponding masks of one sample T test maps (P=5*10-5, cluter size>10, A+B),  two clusters different from these above remained in patient group while none remained in control (which are consistent with hypothesis). 

My questions are: 1. are statistic procedures above correct? if not, coud you please give me some advices. 2. whether paried T test are meaningful or not when no clusters found in interaction F map?  Thank you!

Forums:

YAN Chao-Gan

Fri, 07/12/2019 - 23:58

No. In this case, you can only do the mixed effect analysis first to identify the meaningful interaction effect.

YAN Chao-Gan

Fri, 07/12/2019 - 23:59

No. In this case, you can only do the mixed effect analysis first to identify the meaningful interaction effect.

Aaron_Hsiang

Sun, 07/14/2019 - 00:49

Thank you so much.

Aaron_Hsiang

Mon, 07/15/2019 - 02:03

Dear Dr. Yan,

Now I have identified multiple very small clusters (about 10 or less voxels  for each) from interaction F map using GRF (voxel P=0.01, cluster P=0.05, single tailed) correction.  Should I create mask based on these clusters to perform paired T test within each group and independent two sample T test between groups?  Could you please share me some references about mixed effect analysis using DPABI or similar ones?

Thank you again.

Aaron Hsiang

 

YAN Chao-Gan

Fri, 07/19/2019 - 23:37

You can just extract the values for those clusters (define as ROIs) and plot them or use SPSS to do post-hoc analyses.

Yan, C.G., Rincon-Cortes, M., Raineki, C., Sarro, E., Colcombe, S., Guilfoyle, D.N., Yang, Z., Gerum, S., Biswal, B.B., Milham, M.P., Sullivan, R.M., Castellanos, F.X., 2017. Aberrant development of intrinsic brain activity in a rat model of caregiver maltreatment of offspring. Transl Psychiatry 7, e1005.

Aaron_Hsiang

Sat, 10/19/2019 - 08:40

Dear Dr. Yan,

Is it right to set voxel P=0.02 and cluster P=0.05 when using GRF correction for T-test maps and voxel P=0.01 and cluster P=0.05 for F-test maps? If not, Could you tell me the right setings? Thank you.

AF Xiang

 

 

 

YAN Chao-Gan

Wed, 10/23/2019 - 08:10

We put Voxel P at 0.001 and cluster P at 0.05, also check Two-tailed.