Thresholding after functional connectivity computation

[Jimmyuba1]

Hello experts,

I have currently computed the functional connectivity for each event a subject went through. However, I seem not to understand the explanation in the tutorial as regards thresholding using a non-parametric permutation test. Consequently, I have the following questions:

1. Are the functional connectivity compared across each event in the process 1 and 2 tab or are they compared across each subject (event A on subjects 1 and 2)?

2. I seem not to understand the result gotten after performing the test. A value gets displayed in my MATLAB environment after performing the permutation test. Is that the value that should be used as the threshold?

3. In situations whereby we have more than 2 subjects, how do you compare using process 1 and 2 and perform permutation tests?

[Francois]

Please refer to:

• The Statistics tutorial for a general introduction to non-parametric statistics in Brainstorm and an example for within-subject subject comparisons between two experimental conditions (across trials):
  https://neuroimage.usc.edu/brainstorm/Tutorials/Statistics
• The Group analysis tutorial for an example of group statistics (comparing subject-level averages of two conditions across subjects):
  https://neuroimage.usc.edu/brainstorm/Tutorials/VisualGroup#Group_analysis:_MEG.2FEEG
• Recommended workflows for testing all sorts of data types (you can process connectivity files similarly to time-frequency maps, without the need to normalize them):
  Tutorials/Workflows - Brainstorm

Please get back to us if you still have questions after reading this documentation.