[Eeglablist] Power baseline substraction

Michal Vavrecka vavrecka at fel.cvut.cz
Wed Mar 18 14:24:39 PDT 2015


I am using the eeglab for hemispheric assymetry calculation, so I need to create custom processing pipeline for the output of std_precompute. I know that the ERSP data are stored in *.erspdat file, that contains spectral power for each channel and also baseline (chanxx_ersp and chan_erspbase respectively). The problem is, that each matrix (or vector and matrix) are in different unit, so I do not know how to substract baseline and visualize results outside eeglab. The ersp matrix stores spectral values that range about [-8;8] that resembles spectral power in dB. Suprisingly the baseline values are stored in different units, ranging between 0 100. Can you write me how to convert baseline values to substract them from ersp data? Do I need to log the baseline or there is different transformation?

Thank you for your help


Michal Vavrecka
assistant professor
Karlovo nam. 13
mail: vavrecka at fel.cvut.cz
web: bio.felk.cvut.cz

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