Hi Damiana,

I assume you are using ft_freqanalysis? Then you can extract the delta band either by specifying your frequencies of interest (cfg.foi or cfg.foilim) in advance or by selecting the respective frequency slices from your powerspectrum after the analysis. Have a look at the dimord field in the output structure, it will tell you which dimension of your powspctrm is time, frequency, etc.

HTH,

Marius

Here is a quick guide to ft_freqanalysis from our MEG/EEG course: http://natmeg.se/MEEG_course2018/freqanalysis.html. I hope that might help.

Hello! First define your frequency of interest (here f_o_i) like this:

f_o_i= 1:0.5:55 (here it starts from 1 Hz and computes the spectrum up to 55 Hz in steps of 0.5 Hz)

cfg=[];

cfg.method='mtmfft'; %%% define your method (if you want to keep the time dimension I suggest wavelets, see help ft_freqanalysis for the specifics)

cfg.output='pow';

cfg.taper = 'hanning'; %%% define your taper

cfg.channel='all';

cfg.trials='all';

cfg.keeptrials='no';

cfg.foi=f_o_i;

cfg.tapsmofrq = 4;

Best wishes.

Elisa