[Eeglablist] newtimef() with option baseline NaN: What kind of power values?

[Christian Scharinger]

Dear all,
 
I am wondering what kind of power values I get out of the newtimef() function when I use it to calculate a time-frequency representation with the option 'baseline', NaN. If I understand the description of the function correctly, whith 'baseline' set to NaN I should get a time-frequency representation with no baseline normalization, i.e., I would expect to get absolute power values out of the function. However, when I look at the values in the ersp matrix there are at the higher frequencies some negative power values. Now I'm a little bit confused because I would expect to have only positive numbers when no baseline normalization is performed? Maybe I missed something?
To make it short: What kind of power values does the function newtimef() provide when no baseline is used?
 
I would be happy to get some clarification on that.
 
Many thanks in advance,
best wishes
Christian   
 
--
Dr. Christian Scharinger
Multimodal Interaction Lab
Leibniz-Institut für Wissensmedien (IWM) /
Knowledge Media Research Center Tuebingen
Schleichstraße 6 | 72076 Tuebingen