[Eeglablist] Can i filtering in two different moments?

[tiago lopes]

Hello Dears,I am developing an experiment where i try to evaluate the thalamocortical dysrhytimia in individuals with chronic pain.In order to improve the quality of the collected signal eeg by the removal of artifacts, i am filtring in two different moments:A) Before dividing into epochsB After being divided into epochs  
My question is: Can filtering at two different times compromise the reliability of the collected signal? (ie, in addition to the artifact, am i taking out brain information that compromises the interpretation of the data?)
Below is the script used in data processing.Thanks a lot for the help.
path ='C:\Users\Tiago Lopes\Documents\MATLAB\Script\REPOUSO E IMG\01 Set epochs e ICA (REPOUSO)\';epochs ='C:\Users\Tiago Lopes\Documents\MATLAB\Script\REPOUSO E IMG\TABELA DE EVENTOS 5000ms.txt';name=strcat(path,'*.ASC');d=dir(name);
for j=1:length(d)    filename = d(j).name;    EEG = pop_loadbci( filename, 600 );    EEG = pop_select( EEG,'nochannel',{'FOTO'});    EEG = pop_select( EEG,'nochannel',{'EMGd' 'EMGm'});    EEG = pop_chanedit(EEG, 'lookup','standard-10-5-cap385.elp');    EEG = pop_reref( EEG, [] );    EEG = pop_eegfilt( EEG, 0.5, 30, [], [0], 0, 0, 'fir1', 0);    EEG = pop_importevent( EEG, 'event',epochs,'fields',{'type' 'latency'},'skipline',1,'timeunit',0.001);    EEG = pop_epoch( EEG, {  }, [-.420 4.580], 'epochinfo', 'yes');    EEG = pop_rmbase(EEG,[-300 0]);    EEG = pop_eegfilt( EEG, 1.80, 30, [], [0], 0, 0, 'fir1', 0);    EEG = pop_epoch( EEG, {  }, [-.420 4.580], 'epochinfo', 'yes');    EEG = pop_rmbase(EEG,[-300 0]);    EEG = pop_runica(EEG, 'extended',1,'interupt','on');    EEG = pop_subcomp( EEG, [1 2], 0);    EEG = pop_saveset( EEG, 'filename',d(j).name,'filepath',path);end
Att. Tiago Lopes
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