# [Eeglablist] Time frequency decomposition for 4 subjects across 4 electrodes

Mariam Hovhannisyan mariam.hovhannisyan at duke.edu
Thu Jun 13 13:33:59 PDT 2019

```Hi,

I am trying to compute time frequency for 4 subjects for 4 different electrodes. I am using the pop_newtimef function and am attempting to loop through the ALLEEG structure to access each subject's EEG data. However, I am receiving an error message: index exceeds matrix dimensions. Please see my code below. The star indicates the line that produces this error message:

for j = 1:size(ALLEEG,2)

electrodes = [5 6 7 8];

nbchan = size(electrodes,2);

for elec = 1:nbchan

* [ersp,itc,powbase,times,freqs,erspboot,itcboot] = pop_newtimef(ALLEEG(j),1, electrodes(elec), [ALLEEG(j).xmin ALLEEG(j).xmax]*1000, [3 0.5],'maxfreq', 22, 'padratio', 16,  'plotphase', 'off', 'timesout', 60, 'plotersp','off', 'plotitc','off');

if elec == 1  % create empty arrays if first electrode

allersp = zeros([ size(ersp) nbchan]);

allitc = zeros([ size(itc) nbchan]);

allpowbase = zeros([ size(powbase) nbchan]);

alltimes = zeros([ size(times) nbchan]);

allfreqs = zeros([ size(freqs) nbchan]);

allerspboot = zeros([ size(erspboot) nbchan]);

allitcboot = zeros([ size(itcboot) nbchan]);

end

allersp (:,:,elec) = ersp;

allitc (:,:,elec) = itc;

allpowbase (:,:,elec) = powbase;

alltimes (:,:,elec) = times;

allfreqs (:,:,elec) = freqs;

allerspboot (:,:,elec) = erspboot;

allitcboot (:,:,elec) = itcboot;

ersp_subj{j} = allersp;

times_subj{j} = alltimes(:,:,1);

freqs_subj{j} = allfreqs(:,:,1);

end

end

Is there a simpler or different way to do this in EEGLab?

Best,

Mariam Hovhannisyan

Research Technician

Department of Neurology

Center for Cognitive Neuroscience

Duke University

```