How to calculate post-pre connectivity matrices for multiple subjects

Hi all,

I am a newbie in MATLAB and desperately need help. I have connectivity matrices (51x51) for 33 subjects for pre_intervention and post_intervention scans.

I would like to group all the 33 pre_intervention matrices and 33 post_intervention matrices, then calculate:

Gnew= Gpost- Gpre

And run a paired t-test.

The filenames are saved in this format: ABC_MS001_post_taskA_connectivity.mat

ABC_MS001_pre_taskA_connectivity.mat

ABC_MS002_post_taskA_connectivity.mat

ABC)MS002_pre_taskA_connectivity.mat

How can I load the concatenated Gpre to be subtracted from the concatenated Gpost .mat files?

Answer 1

[KSSV]

postfiles = dir('*post*.mat') ; m = length(postfiles) ; 
prefiles = dir('*pre*.mat') ; n = length(prefiles) ; 
post = zeros(51,51,m) ; 
pre = zeros(51,51,n) ; 
for i = 1:m    % as you said both the files are same in number so one loop 
    load(postfiles(i).name) ; 
    post(:,:,i) = Gpost ;   % name the matrix in the mat file 
    pre(:,:,i) = Gpre ;   % name the matrix in the mat file 
end
Gnew= Gpost- Gpre ;