Dear friends

I have questions regarding the details of fast and slow spindle detection in your  last article ''Spindle activity phase-locked to sleep slow oscillations''.

I know, the EEG signal was filtered with a band-pass width of 3 Hz centered on the detected individual peak frequency of fast and slow spindle.I was Used eeglab filter because FIR filters are zero lag phase ,but dont know haw many order I should set. please help me?

%% Filtering

f_cent=10;

fs=512;%hz

f3db1=f_cent-1.5;

f3db2=f_cent+1.5;

order1=floor((fs/f3db1)*3);% length of the filter in points {default 3*fix(srate/locutoff)}

order2=floor((fs/f3db2)*3);

for i=1:LCH

      xfil(i,:)=eegfilt(x(i,:),fs,f3db1,0,0,order1,0,'fir1'); %([smoothdata] = eegfilt(data,srate,locutoff,hicutoff);) 

      xfil(i,:)=eegfilt(xfil(i,:),fs,0,f3db2,0,order2,0,'fir1');

end