[Eeglablist] ERSP : activity systematically shifted at t=0

Alibou Nabil William Jean-Pierre nabil.alibou at epfl.ch
Mon Sep 2 04:10:43 PDT 2019


I am starting in the eeg analysis field and i was studying the TF analysis of my dataset with newtimef()

but i noticed that the activity, regardless of the event, was always at t = 0s (and for every subject).

Exemple of ERP/ERSP of components from my dataset (with extended epoch) :
https://imgur.com/ptEEpPD

<https://i.imgur.com/ptEEpPD.png>https://imgur.com/yVgDg2k

https://imgur.com/PLLqEMz
https://imgur.com/rUl0q8K
https://imgur.com/ftds9nY


=> However if i test it with a constant signal with a spike at a certain time the spectral activity displayed will be at the corresponding t.
 Im using this parameters :

figure();
        newtimef(EEG.icaact(5,:,:), EEG.pnts, [EEG.xmin EEG.xmax]*1000, EEG.srate,0,'freqscale','linear', ...
            'cycles',[5 0.5],'elocs', EEG.chanlocs, 'chaninfo', EEG.chaninfo,  ...
            'freqs',[5 50], 'maxfreq',50,'baseline',[EEG.xmin EEG.xmax]*1000,'trialbase', 'off','basenorm', 'off', 'plotitc', 'off', ... % divise into 2 portions of frequencies for study easily ?
            'caption','test', 'padratio', 4,'alpha',NaN,'ntimesout',100,'winsize',700, 'erspmax', 0.5);

I have changed almost every parameter but i still have this problem and i don't know the cause, thanks you in advance for your help.
Best regards,

Nabil



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