Good afternoon!

I'm trying to analyze my data but I'm not sure which approach is the best:

I computed PSD for 4 bands (Delta, Theta , Alpha , Beta) per file

Then I'm trying to perform a permutation test but I have this doubt:

Once I've ran the test and before applying alpha threshold I export the result of the test to a Matlab var,

I checked the Matlab var named "pmap", I guess it contains the p-value for every measure (electrode in this case)

Once I've applied aIpha threshold I usually export the file to excel,

It seems like it automatically performed the test over all the 4 EEG bands, however, I would like to perform the permutation test on just one band (Delta) so when I was running the test I specified in the frequency the same Hz I set for Delta band (1.56 - 3.52), but the result I got is different:

when I check the "pmap" var the p-values are very different from p-values in the first file in Delta band (the file tested with 4 bands)

I don't get why?

I would like to understand the best approach for this testing, I followed tutorial but there is no example about psd comparing.

I'm not sure what correction should I apply: I guess it would be a good idea to select "Signals" since I have 19 electrodes being tested at the same time

Thanks in advance!