[Eeglablist] seek help

[Xuening LI]

Hello Arno,


I would like to ask two question and am so sorry to bother you.
My results makes me confused, so I would like to seek your insights.  Thanks a lot
The experiment consists  two  conditions (Action vs NoAction).



All power estimates were normalized using the pre-stimulus baseline window from −500 to −200 ms earlier to movement onset.  Finally, I found that the power of low frequency looks likes unusual (And you can check the figure via this link (picture named Action and NoAction):
https://urldefense.com/v3/__https://www.dropbox.com/scl/fo/ptrysc5ay23amfyof421q/h?rlkey=ivkcqioy24typ4w220vw9o25z&dl=0__;!!Mih3wA!H6CqU7bxPl2smHQyGFH9PVJUbKB2bU84vO4EEqEsptfpYBIX_dS9EU2fJpoSopNY-EIk-QF9tsIQHqVuLOH2xLQZYg$ 
I try to find the reason :
1. artifacts： I did not conduct ICA, and only reject trials ( including artifacts near to the important triggers; if it is a little far, I did not remove trials).
2. low resolution:  I am not sure if it will influence this result. The codes are as follows: 

resolution = 128;
cfg = [];
cfg.output     = 'pow';
cfg.channel    = 'all';
cfg.method     = 'wavelet';
cfg.foi        =  2:0.5:50;
cfg.toi        = (-1:1/resolution:5); % the increment needs to be at least 1/128 Hz so the resolution still ok
cfg.width = linspace(2, 8, length(cfg.foi))
cfg.keeptrials = 'yes';
TFR_data = ft_freqanalysis(cfg, data);



Additionally, I also would like to another question:

Regrding the pre-stimulus baseline, I found the power of low frequecny is so high, which is normal? (original power, I did not conduct normalization). And you can check the figure via this link (picture named pre-stimulus figure (sub1) and pre-stimulus figure (sub2)): 
https://urldefense.com/v3/__https://www.dropbox.com/scl/fo/ptrysc5ay23amfyof421q/h?rlkey=ivkcqioy24typ4w220vw9o25z&dl=0__;!!Mih3wA!H6CqU7bxPl2smHQyGFH9PVJUbKB2bU84vO4EEqEsptfpYBIX_dS9EU2fJpoSopNY-EIk-QF9tsIQHqVuLOH2xLQZYg$ 





Have a good weekend,
Xuening