Hello

I am a bit confused about the ideal way to use randomize for a single group design.

My goal is to test for correlations between FA and % signal change in an ROI

Based on the exchanges that I found on the forum which matched my goals, I used the GLM gui to generate a design matrix (with EV1 as the demeaned % signal change and group set to 1) and a contrast matrix (with 1 and -1, to check for both positive and negative correlations).

I ran the standard randomise command:

randomise -i all_FA_skeletonized -o tbss –m mean_FA_skeleton_mask -d design.mat -t design.con -m <mask_image> -D -n 500 - -T2 –V

 

However, I recently came across the instructions in the TBSS website which says that for a single group simple design, one does not have to use a design or contrast file.

But the website also says that “randomise will automatically select one-sample mode for appropriate design/contrast combinations”.

So here are my questions:

1. Have I done the correct analysis? Should I use: randomise -i OneSamp4D -o OneSampT -1 -v 5 –T (should I use - - T2 here?)

2. If the GLMgui based analysis is indeed correct, then do the output files tstat1 and tstat 2 reflect the 1 and -1 contrasts that I specified?

3. Which output file should I pass for cluster thresholding for multiple comparisons?

4. How do I export the FA vs EV1 correlation data from a cluster that shows a significant correlation?

 

Many thanks as always

Cibu Thomas